Merge remote-tracking branch 'remotes/prometheus/main' into sync-upstream

.github/workflows/lock.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.repository_owner == 'prometheus'
     steps:
-      - uses: dessant/lock-threads@be8aa5be94131386884a6da4189effda9b14aa21 # v4.0.1
+      - uses: dessant/lock-threads@1bf7ec25051fe7c00bdd17e6a7cf3d7bfb7dc771 # v5.0.1
         with:
           process-only: 'issues'
           issue-inactive-days: '180'

.golangci.yml

@@ -23,6 +23,7 @@ linters:
     - nolintlint
     - predeclared
     - revive
+    - testifylint
     - unconvert
     - unused
 
@@ -35,13 +36,9 @@ issues:
     - path: _test.go
       linters:
         - errcheck
-    - path: tsdb/
+    - path: "tsdb/head_wal.go"
       linters:
         - errorlint
-    - path: tsdb/
-      text: "import 'github.com/pkg/errors' is not allowed"
-      linters:
-        - depguard
     - linters:
         - godot
       source: "^// ==="
@@ -81,8 +78,55 @@ linters-settings:
   gofumpt:
     extra-rules: true
   revive:
+    # By default, revive will enable only the linting rules that are named in the configuration file.
+    # So, it's needed to explicitly set in configuration all required rules.
+    # The following configuration enables all the rules from the defaults.toml
+    # https://github.com/mgechev/revive/blob/master/defaults.toml
     rules:
-      # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#unused-parameter
-      - name: unused-parameter
-        severity: warning
+      # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md
+      - name: blank-imports
+      - name: context-as-argument
+        arguments:
+          # allow functions with test or bench signatures
+          - allowTypesBefore: "*testing.T,testing.TB"
+      - name: context-keys-type
+      - name: dot-imports
+      # A lot of false positives: incorrectly identifies channel draining as "empty code block".
+      # See https://github.com/mgechev/revive/issues/386
+      - name: empty-block
         disabled: true
+      - name: error-naming
+      - name: error-return
+      - name: error-strings
+      - name: errorf
+      - name: exported
+      - name: increment-decrement
+      - name: indent-error-flow
+      - name: package-comments
+      - name: range
+      - name: receiver-naming
+      - name: redefines-builtin-id
+      - name: superfluous-else
+      - name: time-naming
+      - name: unexported-return
+      - name: unreachable-code
+      - name: unused-parameter
+        disabled: true
+      - name: var-declaration
+      - name: var-naming
+  testifylint:
+    disable:
+      - float-compare
+      - go-require
+    enable:
+      - bool-compare
+      - compares
+      - empty
+      - error-is-as
+      - error-nil
+      - expected-actual
+      - len
+      - require-error
+      - suite-dont-use-pkg
+      - suite-extra-assert-call
+ 

CHANGELOG.md

@@ -1,21 +1,16 @@
 # Changelog
 
-## 2.48.0-rc.2 / 2023-11-02
+## unreleased
 
-* [ENHANCEMENT] Scraping: Add configuration option for tracking staleness of scraped timestamps. #13060
-* [BUGFIX] Storage: Fix crash caused by incorrect mixed samples handling. #13055
-* [BUGFIX] TSDB: Fix compactor failures by adding min time to histogram chunks. #13062
+* [ENHANCEMENT] TSDB: Make the wlog watcher read segments synchronously when not tailing. #13224
+* [BUGFIX] Agent: Participate in notify calls. #13223
 
-## 2.48.0-rc.1 / 2023-10-24
-
-* [BUGFIX] PromQL: Reduce inefficiency introduced by warnings/annotations and temporarily remove possible non-counter warnings. #13012
-
-## 2.48.0-rc.0 / 2023-10-10
+## 2.48.0 / 2023-11-16
 
 * [CHANGE] Remote-write: respect Retry-After header on 5xx errors. #12677
 * [FEATURE] Alerting: Add AWS SigV4 authentication support for Alertmanager endpoints. #12774
 * [FEATURE] Promtool: Add support for histograms in the TSDB dump command. #12775
-* [FEATURE] PromQL: Add warnings (and annotations) to PromQL query results. #12152 #12982 #12988
+* [FEATURE] PromQL: Add warnings (and annotations) to PromQL query results. #12152 #12982 #12988 #13012
 * [FEATURE] Remote-write: Add Azure AD OAuth authentication support for remote write requests. #12572
 * [ENHANCEMENT] Remote-write: Add a header to count retried remote write requests. #12729
 * [ENHANCEMENT] TSDB: Improve query performance by re-using iterator when moving between series. #12757
@@ -31,6 +26,7 @@
 * [ENHANCEMENT] Scraping: Save memory when scraping by delaying creation of buffer. #12953
 * [ENHANCEMENT] Agent: Allow ingestion of out-of-order samples. #12897
 * [ENHANCEMENT] Promtool: Improve support for native histograms in TSDB analyze command. #12869
+* [ENHANCEMENT] Scraping: Add configuration option for tracking staleness of scraped timestamps. #13060
 * [BUGFIX] SD: Ensure that discovery managers are properly canceled. #10569
 * [BUGFIX] TSDB: Fix PostingsForMatchers race with creating new series. #12558
 * [BUGFIX] TSDB: Fix handling of explicit counter reset header in histograms. #12772
@@ -40,6 +36,8 @@
 * [BUGFIX] Promtool: Fix errors not being reported in check rules command. #12715
 * [BUGFIX] TSDB: Avoid panics reported in logs when head initialization takes a long time. #12876
 * [BUGFIX] TSDB: Ensure that WBL is repaired when possible. #12406
+* [BUGFIX] Storage: Fix crash caused by incorrect mixed samples handling. #13055
+* [BUGFIX] TSDB: Fix compactor failures by adding min time to histogram chunks. #13062
 
 ## 2.47.1 / 2023-10-04
 

Makefile

@@ -93,9 +93,9 @@ endif
 # If we only want to only test go code we have to change the test target
 # which is called by all.
 ifeq ($(GO_ONLY),1)
-test: common-test
+test: common-test check-go-mod-version
 else
-test: common-test ui-build-module ui-test ui-lint
+test: common-test ui-build-module ui-test ui-lint check-go-mod-version
 endif
 
 .PHONY: npm_licenses
@@ -138,3 +138,17 @@ bench_tsdb: $(PROMU)
 cli-documentation:
 	$(GO) run ./cmd/prometheus/ --write-documentation > docs/command-line/prometheus.md
 	$(GO) run ./cmd/promtool/ write-documentation > docs/command-line/promtool.md
+
+.PHONY: check-go-mod-version
+check-go-mod-version:
+	@echo ">> checking go.mod version matching"
+	@./scripts/check-go-mod-version.sh
+
+.PHONY: update-all-go-deps
+update-all-go-deps:
+	@$(MAKE) update-go-deps
+	@echo ">> updating Go dependencies in ./documentation/examples/remote_storage/"
+	@cd ./documentation/examples/remote_storage/ && for m in $$($(GO) list -mod=readonly -m -f '{{ if and (not .Indirect) (not .Main)}}{{.Path}}{{end}}' all); do \
+		$(GO) get -d $$m; \
+	done
+	@cd ./documentation/examples/remote_storage/ && $(GO) mod tidy

Makefile.common

@@ -61,7 +61,7 @@ PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_
 SKIP_GOLANGCI_LINT :=
 GOLANGCI_LINT :=
 GOLANGCI_LINT_OPTS ?=
-GOLANGCI_LINT_VERSION ?= v1.54.2
+GOLANGCI_LINT_VERSION ?= v1.55.2
 # golangci-lint only supports linux, darwin and windows platforms on i386/amd64.
 # windows isn't included here because of the path separator being different.
 ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))

RELEASE.md

@@ -53,7 +53,8 @@ Release cadence of first pre-releases being cut is 6 weeks.
 | v2.46          | 2023-07-12                                 | Julien Pivotto (GitHub: @roidelapluie)      |
 | v2.47          | 2023-08-23                                 | Bryan Boreham (GitHub: @bboreham)           |
 | v2.48          | 2023-10-04                                 | Levi Harrison (GitHub: @LeviHarrison)       |
-| v2.49          | 2023-11-15                                 | **searching for volunteer**                 |
+| v2.49          | 2023-12-05                                 | Bartek Plotka (GitHub: @bwplotka)           |
+| v2.50          | 2024-01-16                                 | **searching for volunteer**                 |
 
 If you are interested in volunteering please create a pull request against the [prometheus/prometheus](https://github.com/prometheus/prometheus) repository and propose yourself for the release series of your choice.
 
@@ -108,14 +109,16 @@ This is also a good time to consider any experimental features and feature
 flags for promotion to stable or for deprecation or ultimately removal. Do any
 of these in pull requests, one per feature.
 
+> NOTE: As a validation step check if all security alerts are closed after this step: https://github.com/prometheus/prometheus/security/dependabot. Sometimes it's ok
+> if not critical and e.g. fix is not released yet (or it does not relate to 
+> upgrading) or when we are unaffected.
+ 
 #### Manually updating Go dependencies
 
 This is usually only needed for `+incompatible` and `v0.0.0` non-semver updates.
 
 ```bash
-make update-go-deps
-git add go.mod go.sum
-git commit -m "Update dependencies"
+make update-all-go-deps
 ```
 
 #### Manually updating React dependencies

VERSION

@@ -1 +1 @@
-2.48.0-rc.2
+2.48.0

cmd/prometheus/main.go

@@ -206,9 +206,15 @@ func (c *flagConfig) setFeatureListOptions(logger log.Logger) error {
 			case "native-histograms":
 				c.tsdb.EnableNativeHistograms = true
 				// Change relevant global variables. Hacky, but it's hard to pass a new option or default to unmarshallers.
-				config.DefaultConfig.GlobalConfig.ScrapeProtocols = config.DefaultNativeHistogramScrapeProtocols
-				config.DefaultGlobalConfig.ScrapeProtocols = config.DefaultNativeHistogramScrapeProtocols
+				config.DefaultConfig.GlobalConfig.ScrapeProtocols = config.DefaultProtoFirstScrapeProtocols
+				config.DefaultGlobalConfig.ScrapeProtocols = config.DefaultProtoFirstScrapeProtocols
 				level.Info(logger).Log("msg", "Experimental native histogram support enabled. Changed default scrape_protocols to prefer PrometheusProto format.", "global.scrape_protocols", fmt.Sprintf("%v", config.DefaultGlobalConfig.ScrapeProtocols))
+			case "created-timestamp-zero-ingestion":
+				c.scrape.EnableCreatedTimestampZeroIngestion = true
+				// Change relevant global variables. Hacky, but it's hard to pass a new option or default to unmarshallers.
+				config.DefaultConfig.GlobalConfig.ScrapeProtocols = config.DefaultProtoFirstScrapeProtocols
+				config.DefaultGlobalConfig.ScrapeProtocols = config.DefaultProtoFirstScrapeProtocols
+				level.Info(logger).Log("msg", "Experimental created timestamp zero ingestion enabled. Changed default scrape_protocols to prefer PrometheusProto format.", "global.scrape_protocols", fmt.Sprintf("%v", config.DefaultGlobalConfig.ScrapeProtocols))
 			case "":
 				continue
 			case "promql-at-modifier", "promql-negative-offset":
@@ -614,14 +620,52 @@ func main() {
 		discoveryManagerNotify  discoveryManager
 	)
 
+	// Kubernetes client metrics are used by Kubernetes SD.
+	// They are registered here in the main function, because SD mechanisms
+	// can only register metrics specific to a SD instance.
+	// Kubernetes client metrics are the same for the whole process -
+	// they are not specific to an SD instance.
+	err = discovery.RegisterK8sClientMetricsWithPrometheus(prometheus.DefaultRegisterer)
+	if err != nil {
+		level.Error(logger).Log("msg", "failed to register Kubernetes client metrics", "err", err)
+		os.Exit(1)
+	}
 	if cfg.enableNewSDManager {
-		discovery.RegisterMetrics()
-		discoveryManagerScrape = discovery.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), discovery.Name("scrape"))
-		discoveryManagerNotify = discovery.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), discovery.Name("notify"))
+		{
+			discMgr := discovery.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), prometheus.DefaultRegisterer, discovery.Name("scrape"))
+			if discMgr == nil {
+				level.Error(logger).Log("msg", "failed to create a discovery manager scrape")
+				os.Exit(1)
+			}
+			discoveryManagerScrape = discMgr
+		}
+
+		{
+			discMgr := discovery.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), prometheus.DefaultRegisterer, discovery.Name("notify"))
+			if discMgr == nil {
+				level.Error(logger).Log("msg", "failed to create a discovery manager notify")
+				os.Exit(1)
+			}
+			discoveryManagerNotify = discMgr
+		}
 	} else {
-		legacymanager.RegisterMetrics()
-		discoveryManagerScrape = legacymanager.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), legacymanager.Name("scrape"))
-		discoveryManagerNotify = legacymanager.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), legacymanager.Name("notify"))
+		{
+			discMgr := legacymanager.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), prometheus.DefaultRegisterer, legacymanager.Name("scrape"))
+			if discMgr == nil {
+				level.Error(logger).Log("msg", "failed to create a discovery manager scrape")
+				os.Exit(1)
+			}
+			discoveryManagerScrape = discMgr
+		}
+
+		{
+			discMgr := legacymanager.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), prometheus.DefaultRegisterer, legacymanager.Name("notify"))
+			if discMgr == nil {
+				level.Error(logger).Log("msg", "failed to create a discovery manager notify")
+				os.Exit(1)
+			}
+			discoveryManagerNotify = discMgr
+		}
 	}
 
 	scrapeManager, err := scrape.NewManager(
@@ -1127,6 +1171,7 @@ func main() {
 				)
 
 				localStorage.Set(db, 0)
+				db.SetWriteNotified(remoteStorage)
 				close(dbOpen)
 				<-cancel
 				return nil
@@ -1448,6 +1493,10 @@ func (n notReadyAppender) UpdateMetadata(ref storage.SeriesRef, l labels.Labels,
 	return 0, tsdb.ErrNotReady
 }
 
+func (n notReadyAppender) AppendCTZeroSample(ref storage.SeriesRef, l labels.Labels, t, ct int64) (storage.SeriesRef, error) {
+	return 0, tsdb.ErrNotReady
+}
+
 func (n notReadyAppender) Commit() error { return tsdb.ErrNotReady }
 
 func (n notReadyAppender) Rollback() error { return tsdb.ErrNotReady }
@@ -1586,7 +1635,6 @@ func (opts tsdbOptions) ToTSDBOptions() tsdb.Options {
 		RetentionDuration:              int64(time.Duration(opts.RetentionDuration) / time.Millisecond),
 		MaxBytes:                       int64(opts.MaxBytes),
 		NoLockfile:                     opts.NoLockfile,
-		AllowOverlappingCompaction:     true,
 		WALCompression:                 wlog.ParseCompressionType(opts.WALCompression, opts.WALCompressionType),
 		HeadChunksWriteQueueSize:       opts.HeadChunksWriteQueueSize,
 		SamplesPerChunk:                opts.SamplesPerChunk,

cmd/prometheus/main_test.go

@@ -346,7 +346,7 @@ func getCurrentGaugeValuesFor(t *testing.T, reg prometheus.Gatherer, metricNames
 				continue
 			}
 
-			require.Equal(t, 1, len(g.GetMetric()))
+			require.Len(t, g.GetMetric(), 1)
 			if _, ok := res[m]; ok {
 				t.Error("expected only one metric family for", m)
 				t.FailNow()

cmd/prometheus/query_log_test.go

@@ -284,7 +284,7 @@ func (p *queryLogTest) run(t *testing.T) {
 
 	if !p.enabledAtStart {
 		p.query(t)
-		require.Equal(t, 0, len(readQueryLog(t, queryLogFile.Name())))
+		require.Empty(t, readQueryLog(t, queryLogFile.Name()))
 		p.setQueryLog(t, queryLogFile.Name())
 		p.reloadConfig(t)
 	}
@@ -309,7 +309,7 @@ func (p *queryLogTest) run(t *testing.T) {
 	p.query(t)
 
 	ql = readQueryLog(t, queryLogFile.Name())
-	require.Equal(t, qc, len(ql))
+	require.Len(t, ql, qc)
 
 	qc = len(ql)
 	p.setQueryLog(t, queryLogFile.Name())
@@ -320,7 +320,7 @@ func (p *queryLogTest) run(t *testing.T) {
 
 	ql = readQueryLog(t, queryLogFile.Name())
 	if p.exactQueryCount() {
-		require.Equal(t, qc, len(ql))
+		require.Len(t, ql, qc)
 	} else {
 		require.Greater(t, len(ql), qc, "no queries logged")
 	}
@@ -340,7 +340,7 @@ func (p *queryLogTest) run(t *testing.T) {
 	require.NoError(t, os.Rename(queryLogFile.Name(), newFile.Name()))
 	ql = readQueryLog(t, newFile.Name())
 	if p.exactQueryCount() {
-		require.Equal(t, qc, len(ql))
+		require.Len(t, ql, qc)
 	}
 	p.validateLastQuery(t, ql)
 	qc = len(ql)
@@ -351,7 +351,7 @@ func (p *queryLogTest) run(t *testing.T) {
 
 	ql = readQueryLog(t, newFile.Name())
 	if p.exactQueryCount() {
-		require.Equal(t, qc, len(ql))
+		require.Len(t, ql, qc)
 	} else {
 		require.Greater(t, len(ql), qc, "no queries logged")
 	}

cmd/promtool/backfill_test.go

@@ -61,7 +61,7 @@ func queryAllSeries(t testing.TB, q storage.Querier, expectedMinTime, expectedMa
 
 func testBlocks(t *testing.T, db *tsdb.DB, expectedMinTime, expectedMaxTime, expectedBlockDuration int64, expectedSamples []backfillSample, expectedNumBlocks int) {
 	blocks := db.Blocks()
-	require.Equal(t, expectedNumBlocks, len(blocks), "did not create correct number of blocks")
+	require.Len(t, blocks, expectedNumBlocks, "did not create correct number of blocks")
 
 	for i, block := range blocks {
 		require.Equal(t, block.MinTime()/expectedBlockDuration, (block.MaxTime()-1)/expectedBlockDuration, "block %d contains data outside of one aligned block duration", i)

cmd/promtool/main.go

@@ -36,6 +36,7 @@ import (
 	"github.com/google/pprof/profile"
 	"github.com/prometheus/client_golang/api"
 	v1 "github.com/prometheus/client_golang/api/prometheus/v1"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/prometheus/client_golang/prometheus/testutil/promlint"
 	config_util "github.com/prometheus/common/config"
@@ -198,6 +199,7 @@ func main() {
 
 	testCmd := app.Command("test", "Unit testing.")
 	testRulesCmd := testCmd.Command("rules", "Unit tests for rules.")
+	testRulesRun := testRulesCmd.Flag("run", "If set, will only run test groups whose names match the regular expression. Can be specified multiple times.").Strings()
 	testRulesFiles := testRulesCmd.Arg(
 		"test-rule-file",
 		"The unit test file.",
@@ -316,7 +318,7 @@ func main() {
 
 	switch parsedCmd {
 	case sdCheckCmd.FullCommand():
-		os.Exit(CheckSD(*sdConfigFile, *sdJobName, *sdTimeout, noDefaultScrapePort))
+		os.Exit(CheckSD(*sdConfigFile, *sdJobName, *sdTimeout, noDefaultScrapePort, prometheus.DefaultRegisterer))
 
 	case checkConfigCmd.FullCommand():
 		os.Exit(CheckConfig(*agentMode, *checkConfigSyntaxOnly, newLintConfig(*checkConfigLint, *checkConfigLintFatal), *configFiles...))
@@ -366,6 +368,7 @@ func main() {
 				EnableAtModifier:     true,
 				EnableNegativeOffset: true,
 			},
+			*testRulesRun,
 			*testRulesFiles...),
 		)
 
@@ -411,7 +414,7 @@ func checkExperimental(f bool) {
 	}
 }
 
-var lintError = fmt.Errorf("lint error")
+var errLint = fmt.Errorf("lint error")
 
 type lintConfig struct {
 	all            bool
@@ -763,7 +766,7 @@ func checkRulesFromStdin(ls lintConfig) (bool, bool) {
 		fmt.Fprintln(os.Stderr, "  FAILED:")
 		for _, e := range errs {
 			fmt.Fprintln(os.Stderr, e.Error())
-			hasErrors = hasErrors || !errors.Is(e, lintError)
+			hasErrors = hasErrors || !errors.Is(e, errLint)
 		}
 		if hasErrors {
 			return failed, hasErrors
@@ -776,7 +779,7 @@ func checkRulesFromStdin(ls lintConfig) (bool, bool) {
 		}
 		failed = true
 		for _, err := range errs {
-			hasErrors = hasErrors || !errors.Is(err, lintError)
+			hasErrors = hasErrors || !errors.Is(err, errLint)
 		}
 	} else {
 		fmt.Printf("  SUCCESS: %d rules found\n", n)
@@ -797,7 +800,7 @@ func checkRules(files []string, ls lintConfig) (bool, bool) {
 			fmt.Fprintln(os.Stderr, "  FAILED:")
 			for _, e := range errs {
 				fmt.Fprintln(os.Stderr, e.Error())
-				hasErrors = hasErrors || !errors.Is(e, lintError)
+				hasErrors = hasErrors || !errors.Is(e, errLint)
 			}
 			if hasErrors {
 				continue
@@ -810,7 +813,7 @@ func checkRules(files []string, ls lintConfig) (bool, bool) {
 			}
 			failed = true
 			for _, err := range errs {
-				hasErrors = hasErrors || !errors.Is(err, lintError)
+				hasErrors = hasErrors || !errors.Is(err, errLint)
 			}
 		} else {
 			fmt.Printf("  SUCCESS: %d rules found\n", n)
@@ -837,7 +840,7 @@ func checkRuleGroups(rgs *rulefmt.RuleGroups, lintSettings lintConfig) (int, []e
 				})
 			}
 			errMessage += "Might cause inconsistency while recording expressions"
-			return 0, []error{fmt.Errorf("%w %s", lintError, errMessage)}
+			return 0, []error{fmt.Errorf("%w %s", errLint, errMessage)}
 		}
 	}
 

cmd/promtool/main_test.go

@@ -56,7 +56,7 @@ func TestQueryRange(t *testing.T) {
 	defer s.Close()
 
 	urlObject, err := url.Parse(s.URL)
-	require.Equal(t, nil, err)
+	require.NoError(t, err)
 
 	p := &promqlPrinter{}
 	exitCode := QueryRange(urlObject, http.DefaultTransport, map[string]string{}, "up", "0", "300", 0, p)
@@ -79,7 +79,7 @@ func TestQueryInstant(t *testing.T) {
 	defer s.Close()
 
 	urlObject, err := url.Parse(s.URL)
-	require.Equal(t, nil, err)
+	require.NoError(t, err)
 
 	p := &promqlPrinter{}
 	exitCode := QueryInstant(urlObject, http.DefaultTransport, "up", "300", p)

cmd/promtool/rules_test.go

@@ -91,13 +91,13 @@ func TestBackfillRuleIntegration(t *testing.T) {
 				for _, err := range errs {
 					require.NoError(t, err)
 				}
-				require.Equal(t, 3, len(ruleImporter.groups))
+				require.Len(t, ruleImporter.groups, 3)
 				group1 := ruleImporter.groups[path1+";group0"]
 				require.NotNil(t, group1)
 				const defaultInterval = 60
 				require.Equal(t, defaultInterval*time.Second, group1.Interval())
 				gRules := group1.Rules()
-				require.Equal(t, 1, len(gRules))
+				require.Len(t, gRules, 1)
 				require.Equal(t, "rule1", gRules[0].Name())
 				require.Equal(t, "ruleExpr", gRules[0].Query().String())
 				require.Equal(t, 1, gRules[0].Labels().Len())
@@ -106,7 +106,7 @@ func TestBackfillRuleIntegration(t *testing.T) {
 				require.NotNil(t, group2)
 				require.Equal(t, defaultInterval*time.Second, group2.Interval())
 				g2Rules := group2.Rules()
-				require.Equal(t, 2, len(g2Rules))
+				require.Len(t, g2Rules, 2)
 				require.Equal(t, "grp2_rule1", g2Rules[0].Name())
 				require.Equal(t, "grp2_rule1_expr", g2Rules[0].Query().String())
 				require.Equal(t, 0, g2Rules[0].Labels().Len())
@@ -122,7 +122,7 @@ func TestBackfillRuleIntegration(t *testing.T) {
 				require.NoError(t, err)
 
 				blocks := db.Blocks()
-				require.Equal(t, (i+1)*tt.expectedBlockCount, len(blocks))
+				require.Len(t, blocks, (i+1)*tt.expectedBlockCount)
 
 				q, err := db.Querier(math.MinInt64, math.MaxInt64)
 				require.NoError(t, err)

cmd/promtool/sd.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/discovery"
@@ -37,7 +38,7 @@ type sdCheckResult struct {
 }
 
 // CheckSD performs service discovery for the given job name and reports the results.
-func CheckSD(sdConfigFiles, sdJobName string, sdTimeout time.Duration, noDefaultScrapePort bool) int {
+func CheckSD(sdConfigFiles, sdJobName string, sdTimeout time.Duration, noDefaultScrapePort bool, registerer prometheus.Registerer) int {
 	logger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stderr))
 
 	cfg, err := config.LoadFile(sdConfigFiles, false, false, logger)
@@ -77,7 +78,7 @@ func CheckSD(sdConfigFiles, sdJobName string, sdTimeout time.Duration, noDefault
 	defer cancel()
 
 	for _, cfg := range scrapeConfig.ServiceDiscoveryConfigs {
-		d, err := cfg.NewDiscoverer(discovery.DiscovererOptions{Logger: logger})
+		d, err := cfg.NewDiscoverer(discovery.DiscovererOptions{Logger: logger, Registerer: registerer})
 		if err != nil {
 			fmt.Fprintln(os.Stderr, "Could not create new discoverer", err)
 			return failureExitCode

cmd/promtool/sd_test.go

@@ -35,7 +35,7 @@ func TestSDCheckResult(t *testing.T) {
 	}}
 
 	reg, err := relabel.NewRegexp("(.*)")
-	require.Nil(t, err)
+	require.NoError(t, err)
 
 	scrapeConfig := &config.ScrapeConfig{
 		ScrapeInterval: model.Duration(1 * time.Minute),

cmd/promtool/testdata/rules_run.yml

@@ -0,0 +1,30 @@
+rule_files:
+  - rules.yml
+
+evaluation_interval: 1m
+
+# Minimal test cases to check focus on a rule group.
+tests:
+  - name: correct test
+    input_series:
+      - series: test
+        values: 1
+
+    promql_expr_test:
+      - expr: test
+        eval_time: 0
+        exp_samples:
+          - value: 1
+            labels: test
+
+  - name: wrong test
+    input_series:
+      - series: test
+        values: 0
+
+    promql_expr_test:
+      - expr: test
+        eval_time: 0
+        exp_samples:
+          - value: 1
+            labels: test

cmd/promtool/unittest.go

@@ -26,6 +26,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/grafana/regexp"
 	"github.com/prometheus/common/model"
 	"gopkg.in/yaml.v2"
 
@@ -39,11 +40,16 @@ import (
 
 // RulesUnitTest does unit testing of rules based on the unit testing files provided.
 // More info about the file format can be found in the docs.
-func RulesUnitTest(queryOpts promql.LazyLoaderOpts, files ...string) int {
+func RulesUnitTest(queryOpts promql.LazyLoaderOpts, runStrings []string, files ...string) int {
 	failed := false
 
+	var run *regexp.Regexp
+	if runStrings != nil {
+		run = regexp.MustCompile(strings.Join(runStrings, "|"))
+	}
+
 	for _, f := range files {
-		if errs := ruleUnitTest(f, queryOpts); errs != nil {
+		if errs := ruleUnitTest(f, queryOpts, run); errs != nil {
 			fmt.Fprintln(os.Stderr, "  FAILED:")
 			for _, e := range errs {
 				fmt.Fprintln(os.Stderr, e.Error())
@@ -61,7 +67,7 @@ func RulesUnitTest(queryOpts promql.LazyLoaderOpts, files ...string) int {
 	return successExitCode
 }
 
-func ruleUnitTest(filename string, queryOpts promql.LazyLoaderOpts) []error {
+func ruleUnitTest(filename string, queryOpts promql.LazyLoaderOpts, run *regexp.Regexp) []error {
 	fmt.Println("Unit Testing: ", filename)
 
 	b, err := os.ReadFile(filename)
@@ -96,6 +102,10 @@ func ruleUnitTest(filename string, queryOpts promql.LazyLoaderOpts) []error {
 	// Testing.
 	var errs []error
 	for _, t := range unitTestInp.Tests {
+		if !matchesRun(t.TestGroupName, run) {
+			continue
+		}
+
 		if t.Interval == 0 {
 			t.Interval = unitTestInp.EvaluationInterval
 		}
@@ -111,6 +121,14 @@ func ruleUnitTest(filename string, queryOpts promql.LazyLoaderOpts) []error {
 	return nil
 }
 
+func matchesRun(name string, run *regexp.Regexp) bool {
+	if run == nil {
+		return true
+	}
+
+	return run.MatchString(name)
+}
+
 // unitTestFile holds the contents of a single unit test file.
 type unitTestFile struct {
 	RuleFiles          []string       `yaml:"rule_files"`

cmd/promtool/unittest_test.go

@@ -125,7 +125,60 @@ func TestRulesUnitTest(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := RulesUnitTest(tt.queryOpts, tt.args.files...); got != tt.want {
+			if got := RulesUnitTest(tt.queryOpts, nil, tt.args.files...); got != tt.want {
+				t.Errorf("RulesUnitTest() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRulesUnitTestRun(t *testing.T) {
+	type args struct {
+		run   []string
+		files []string
+	}
+	tests := []struct {
+		name      string
+		args      args
+		queryOpts promql.LazyLoaderOpts
+		want      int
+	}{
+		{
+			name: "Test all without run arg",
+			args: args{
+				run:   nil,
+				files: []string{"./testdata/rules_run.yml"},
+			},
+			want: 1,
+		},
+		{
+			name: "Test all with run arg",
+			args: args{
+				run:   []string{"correct", "wrong"},
+				files: []string{"./testdata/rules_run.yml"},
+			},
+			want: 1,
+		},
+		{
+			name: "Test correct",
+			args: args{
+				run:   []string{"correct"},
+				files: []string{"./testdata/rules_run.yml"},
+			},
+			want: 0,
+		},
+		{
+			name: "Test wrong",
+			args: args{
+				run:   []string{"wrong"},
+				files: []string{"./testdata/rules_run.yml"},
+			},
+			want: 1,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := RulesUnitTest(tt.queryOpts, tt.args.run, tt.args.files...); got != tt.want {
 				t.Errorf("RulesUnitTest() = %v, want %v", got, tt.want)
 			}
 		})

config/config.go

@@ -454,12 +454,19 @@ var (
 		OpenMetricsText1_0_0: "application/openmetrics-text;version=1.0.0",
 	}
 
+	// DefaultScrapeProtocols is the set of scrape protocols that will be proposed
+	// to scrape target, ordered by priority.
 	DefaultScrapeProtocols = []ScrapeProtocol{
 		OpenMetricsText1_0_0,
 		OpenMetricsText0_0_1,
 		PrometheusText0_0_4,
 	}
-	DefaultNativeHistogramScrapeProtocols = []ScrapeProtocol{
+
+	// DefaultProtoFirstScrapeProtocols is like DefaultScrapeProtocols, but it
+	// favors protobuf Prometheus exposition format.
+	// Used by default for certain feature-flags like
+	// "native-histograms" and "created-timestamp-zero-ingestion".
+	DefaultProtoFirstScrapeProtocols = []ScrapeProtocol{
 		PrometheusProto,
 		OpenMetricsText1_0_0,
 		OpenMetricsText0_0_1,

config/config_test.go

@@ -568,6 +568,7 @@ var expectedConf = &Config{
 			ServiceDiscoveryConfigs: discovery.Configs{
 				&xds.KumaSDConfig{
 					Server:           "http://kuma-control-plane.kuma-system.svc:5676",
+					ClientID:         "main-prometheus",
 					HTTPClientConfig: config.DefaultHTTPClientConfig,
 					RefreshInterval:  model.Duration(15 * time.Second),
 					FetchTimeout:     model.Duration(2 * time.Minute),
@@ -1457,8 +1458,8 @@ func TestRemoteWriteRetryOnRateLimit(t *testing.T) {
 	got := &Config{}
 	require.NoError(t, yaml.UnmarshalStrict(out, got))
 
-	require.Equal(t, true, got.RemoteWriteConfigs[0].QueueConfig.RetryOnRateLimit)
-	require.Equal(t, false, got.RemoteWriteConfigs[1].QueueConfig.RetryOnRateLimit)
+	require.True(t, got.RemoteWriteConfigs[0].QueueConfig.RetryOnRateLimit)
+	require.False(t, got.RemoteWriteConfigs[1].QueueConfig.RetryOnRateLimit)
 }
 
 func TestLoadConfig(t *testing.T) {
@@ -1475,9 +1476,9 @@ func TestLoadConfig(t *testing.T) {
 func TestScrapeIntervalLarger(t *testing.T) {
 	c, err := LoadFile("testdata/scrape_interval_larger.good.yml", false, false, log.NewNopLogger())
 	require.NoError(t, err)
-	require.Equal(t, 1, len(c.ScrapeConfigs))
+	require.Len(t, c.ScrapeConfigs, 1)
 	for _, sc := range c.ScrapeConfigs {
-		require.Equal(t, true, sc.ScrapeInterval >= sc.ScrapeTimeout)
+		require.GreaterOrEqual(t, sc.ScrapeInterval, sc.ScrapeTimeout)
 	}
 }
 
@@ -1493,7 +1494,7 @@ func TestElideSecrets(t *testing.T) {
 	yamlConfig := string(config)
 
 	matches := secretRe.FindAllStringIndex(yamlConfig, -1)
-	require.Equal(t, 22, len(matches), "wrong number of secret matches found")
+	require.Len(t, matches, 22, "wrong number of secret matches found")
 	require.NotContains(t, yamlConfig, "mysecret",
 		"yaml marshal reveals authentication credentials.")
 }
@@ -2063,7 +2064,7 @@ func TestAgentMode(t *testing.T) {
 
 	c, err := LoadFile("testdata/agent_mode.without_remote_writes.yml", true, false, log.NewNopLogger())
 	require.NoError(t, err)
-	require.Len(t, c.RemoteWriteConfigs, 0)
+	require.Empty(t, c.RemoteWriteConfigs)
 
 	c, err = LoadFile("testdata/agent_mode.good.yml", true, false, log.NewNopLogger())
 	require.NoError(t, err)
@@ -2257,5 +2258,5 @@ func TestScrapeConfigDisableCompression(t *testing.T) {
 	got := &Config{}
 	require.NoError(t, yaml.UnmarshalStrict(out, got))
 
-	require.Equal(t, false, got.ScrapeConfigs[0].EnableCompression)
+	require.False(t, got.ScrapeConfigs[0].EnableCompression)
 }

config/testdata/conf.good.yml

@@ -221,6 +221,7 @@ scrape_configs:
 
     kuma_sd_configs:
       - server: http://kuma-control-plane.kuma-system.svc:5676
+        client_id: main-prometheus
 
   - job_name: service-marathon
     marathon_sd_configs:

config/testdata/roundtrip.good.yml

@@ -108,6 +108,7 @@ scrape_configs:
 
     kuma_sd_configs:
       - server: http://kuma-control-plane.kuma-system.svc:5676
+        client_id: main-prometheus
 
     marathon_sd_configs:
       - servers:

discovery/README.md

@@ -234,6 +234,11 @@ type Config interface {
 
 type DiscovererOptions struct {
 	Logger log.Logger
+
+	// A registerer for the Discoverer's metrics.
+	Registerer prometheus.Registerer
+	
+	HTTPClientOptions []config.HTTPClientOption
 }
 ```
 

discovery/aws/ec2.go

@@ -30,6 +30,7 @@ import (
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -101,7 +102,7 @@ func (*EC2SDConfig) Name() string { return "ec2" }
 
 // NewDiscoverer returns a Discoverer for the EC2 Config.
 func (c *EC2SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewEC2Discovery(c, opts.Logger), nil
+	return NewEC2Discovery(c, opts.Logger, opts.Registerer), nil
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface for the EC2 Config.
@@ -147,7 +148,7 @@ type EC2Discovery struct {
 }
 
 // NewEC2Discovery returns a new EC2Discovery which periodically refreshes its targets.
-func NewEC2Discovery(conf *EC2SDConfig, logger log.Logger) *EC2Discovery {
+func NewEC2Discovery(conf *EC2SDConfig, logger log.Logger, reg prometheus.Registerer) *EC2Discovery {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -156,10 +157,13 @@ func NewEC2Discovery(conf *EC2SDConfig, logger log.Logger) *EC2Discovery {
 		cfg:    conf,
 	}
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"ec2",
-		time.Duration(d.cfg.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "ec2",
+			Interval: time.Duration(d.cfg.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d
 }

discovery/aws/lightsail.go

@@ -29,6 +29,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/lightsail"
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -84,7 +85,7 @@ func (*LightsailSDConfig) Name() string { return "lightsail" }
 
 // NewDiscoverer returns a Discoverer for the Lightsail Config.
 func (c *LightsailSDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewLightsailDiscovery(c, opts.Logger), nil
+	return NewLightsailDiscovery(c, opts.Logger, opts.Registerer), nil
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface for the Lightsail Config.
@@ -121,7 +122,7 @@ type LightsailDiscovery struct {
 }
 
 // NewLightsailDiscovery returns a new LightsailDiscovery which periodically refreshes its targets.
-func NewLightsailDiscovery(conf *LightsailSDConfig, logger log.Logger) *LightsailDiscovery {
+func NewLightsailDiscovery(conf *LightsailSDConfig, logger log.Logger, reg prometheus.Registerer) *LightsailDiscovery {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -129,10 +130,13 @@ func NewLightsailDiscovery(conf *LightsailSDConfig, logger log.Logger) *Lightsai
 		cfg: conf,
 	}
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"lightsail",
-		time.Duration(d.cfg.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "lightsail",
+			Interval: time.Duration(d.cfg.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d
 }

discovery/azure/azure.go

@@ -28,9 +28,10 @@ import (
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/arm"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/cloud"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
+	"github.com/Azure/azure-sdk-for-go/sdk/azcore/to"
 	"github.com/Azure/azure-sdk-for-go/sdk/azidentity"
-	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute/v4"
-	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/network/armnetwork/v2"
+	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute/v5"
+	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/network/armnetwork/v4"
 	cache "github.com/Code-Hex/go-generics-cache"
 	"github.com/Code-Hex/go-generics-cache/policy/lru"
 	"github.com/go-kit/log"
@@ -78,17 +79,6 @@ var (
 		AuthenticationMethod: authMethodOAuth,
 		HTTPClientConfig:     config_util.DefaultHTTPClientConfig,
 	}
-
-	failuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_azure_failures_total",
-			Help: "Number of Azure service discovery refresh failures.",
-		})
-	cacheHitCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_azure_cache_hit_total",
-			Help: "Number of cache hit during refresh.",
-		})
 )
 
 var environments = map[string]cloud.Configuration{
@@ -105,7 +95,7 @@ func CloudConfigurationFromName(name string) (cloud.Configuration, error) {
 	name = strings.ToUpper(name)
 	env, ok := environments[name]
 	if !ok {
-		return env, fmt.Errorf("There is no cloud configuration matching the name %q", name)
+		return env, fmt.Errorf("there is no cloud configuration matching the name %q", name)
 	}
 
 	return env, nil
@@ -113,8 +103,6 @@ func CloudConfigurationFromName(name string) (cloud.Configuration, error) {
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(failuresCount)
-	prometheus.MustRegister(cacheHitCount)
 }
 
 // SDConfig is the configuration for Azure based service discovery.
@@ -137,7 +125,7 @@ func (*SDConfig) Name() string { return "azure" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger), nil
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 func validateAuthParam(param, name string) error {
@@ -180,14 +168,16 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 
 type Discovery struct {
 	*refresh.Discovery
-	logger log.Logger
-	cfg    *SDConfig
-	port   int
-	cache  *cache.Cache[string, *armnetwork.Interface]
+	logger        log.Logger
+	cfg           *SDConfig
+	port          int
+	cache         *cache.Cache[string, *armnetwork.Interface]
+	failuresCount prometheus.Counter
+	cacheHitCount prometheus.Counter
 }
 
 // NewDiscovery returns a new AzureDiscovery which periodically refreshes its targets.
-func NewDiscovery(cfg *SDConfig, logger log.Logger) *Discovery {
+func NewDiscovery(cfg *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -197,16 +187,30 @@ func NewDiscovery(cfg *SDConfig, logger log.Logger) *Discovery {
 		port:   cfg.Port,
 		logger: logger,
 		cache:  l,
+		failuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_azure_failures_total",
+				Help: "Number of Azure service discovery refresh failures.",
+			}),
+		cacheHitCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_azure_cache_hit_total",
+				Help: "Number of cache hit during refresh.",
+			}),
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"azure",
-		time.Duration(cfg.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "azure",
+			Interval: time.Duration(cfg.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+			Metrics:  []prometheus.Collector{d.failuresCount, d.cacheHitCount},
+		},
 	)
 
-	return d
+	return d, nil
 }
 
 // azureClient represents multiple Azure Resource Manager providers.
@@ -304,6 +308,7 @@ type virtualMachine struct {
 	Location          string
 	OsType            string
 	ScaleSet          string
+	InstanceID        string
 	Tags              map[string]*string
 	NetworkInterfaces []string
 	Size              string
@@ -328,14 +333,14 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 
 	client, err := createAzureClient(*d.cfg)
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, fmt.Errorf("could not create Azure client: %w", err)
 	}
 	client.logger = d.logger
 
 	machines, err := client.getVMs(ctx, d.cfg.ResourceGroup)
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, fmt.Errorf("could not get virtual machines: %w", err)
 	}
 
@@ -344,14 +349,14 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 	// Load the vms managed by scale sets.
 	scaleSets, err := client.getScaleSets(ctx, d.cfg.ResourceGroup)
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, fmt.Errorf("could not get virtual machine scale sets: %w", err)
 	}
 
 	for _, scaleSet := range scaleSets {
 		scaleSetVms, err := client.getScaleSetVMs(ctx, scaleSet)
 		if err != nil {
-			failuresCount.Inc()
+			d.failuresCount.Inc()
 			return nil, fmt.Errorf("could not get virtual machine scale set vms: %w", err)
 		}
 		machines = append(machines, scaleSetVms...)
@@ -402,9 +407,13 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 				var networkInterface *armnetwork.Interface
 				if v, ok := d.getFromCache(nicID); ok {
 					networkInterface = v
-					cacheHitCount.Add(1)
+					d.cacheHitCount.Add(1)
 				} else {
-					networkInterface, err = client.getNetworkInterfaceByID(ctx, nicID)
+					if vm.ScaleSet == "" {
+						networkInterface, err = client.getVMNetworkInterfaceByID(ctx, nicID)
+					} else {
+						networkInterface, err = client.getVMScaleSetVMNetworkInterfaceByID(ctx, nicID, vm.ScaleSet, vm.InstanceID)
+					}
 					if err != nil {
 						if errors.Is(err, errorNotFound) {
 							level.Warn(d.logger).Log("msg", "Network interface does not exist", "name", nicID, "err", err)
@@ -461,7 +470,7 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 	var tg targetgroup.Group
 	for tgt := range ch {
 		if tgt.err != nil {
-			failuresCount.Inc()
+			d.failuresCount.Inc()
 			return nil, fmt.Errorf("unable to complete Azure service discovery: %w", tgt.err)
 		}
 		if tgt.labelSet != nil {
@@ -622,6 +631,7 @@ func mapFromVMScaleSetVM(vm armcompute.VirtualMachineScaleSetVM, scaleSetName st
 		Location:          *(vm.Location),
 		OsType:            osType,
 		ScaleSet:          scaleSetName,
+		InstanceID:        *(vm.InstanceID),
 		Tags:              tags,
 		NetworkInterfaces: networkInterfaces,
 		Size:              size,
@@ -630,21 +640,41 @@ func mapFromVMScaleSetVM(vm armcompute.VirtualMachineScaleSetVM, scaleSetName st
 
 var errorNotFound = errors.New("network interface does not exist")
 
-// getNetworkInterfaceByID gets the network interface.
+// getVMNetworkInterfaceByID gets the network interface.
 // If a 404 is returned from the Azure API, `errorNotFound` is returned.
-func (client *azureClient) getNetworkInterfaceByID(ctx context.Context, networkInterfaceID string) (*armnetwork.Interface, error) {
+func (client *azureClient) getVMNetworkInterfaceByID(ctx context.Context, networkInterfaceID string) (*armnetwork.Interface, error) {
 	r, err := newAzureResourceFromID(networkInterfaceID, client.logger)
 	if err != nil {
 		return nil, fmt.Errorf("could not parse network interface ID: %w", err)
 	}
 
-	resp, err := client.nic.Get(ctx, r.ResourceGroupName, r.Name, nil)
+	resp, err := client.nic.Get(ctx, r.ResourceGroupName, r.Name, &armnetwork.InterfacesClientGetOptions{Expand: to.Ptr("IPConfigurations/PublicIPAddress")})
 	if err != nil {
 		var responseError *azcore.ResponseError
 		if errors.As(err, &responseError) && responseError.StatusCode == http.StatusNotFound {
 			return nil, errorNotFound
 		}
-		return nil, fmt.Errorf("Failed to retrieve Interface %v with error: %w", networkInterfaceID, err)
+		return nil, fmt.Errorf("failed to retrieve Interface %v with error: %w", networkInterfaceID, err)
+	}
+
+	return &resp.Interface, nil
+}
+
+// getVMScaleSetVMNetworkInterfaceByID gets the network interface.
+// If a 404 is returned from the Azure API, `errorNotFound` is returned.
+func (client *azureClient) getVMScaleSetVMNetworkInterfaceByID(ctx context.Context, networkInterfaceID, scaleSetName, instanceID string) (*armnetwork.Interface, error) {
+	r, err := newAzureResourceFromID(networkInterfaceID, client.logger)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse network interface ID: %w", err)
+	}
+
+	resp, err := client.nic.GetVirtualMachineScaleSetNetworkInterface(ctx, r.ResourceGroupName, scaleSetName, instanceID, r.Name, &armnetwork.InterfacesClientGetVirtualMachineScaleSetNetworkInterfaceOptions{Expand: to.Ptr("IPConfigurations/PublicIPAddress")})
+	if err != nil {
+		var responseError *azcore.ResponseError
+		if errors.As(err, &responseError) && responseError.StatusCode == http.StatusNotFound {
+			return nil, errorNotFound
+		}
+		return nil, fmt.Errorf("failed to retrieve Interface %v with error: %w", networkInterfaceID, err)
 	}
 
 	return &resp.Interface, nil

discovery/azure/azure_test.go

@@ -17,7 +17,7 @@ import (
 	"testing"
 
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/arm"
-	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute/v4"
+	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute/v5"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
 )
@@ -142,6 +142,7 @@ func TestMapFromVMScaleSetVMWithEmptyTags(t *testing.T) {
 	vmSize := armcompute.VirtualMachineSizeTypes(size)
 	osType := armcompute.OperatingSystemTypesLinux
 	vmType := "type"
+	instanceID := "123"
 	location := "westeurope"
 	computerName := "computer_name"
 	networkProfile := armcompute.NetworkProfile{
@@ -166,6 +167,7 @@ func TestMapFromVMScaleSetVMWithEmptyTags(t *testing.T) {
 		ID:         &id,
 		Name:       &name,
 		Type:       &vmType,
+		InstanceID: &instanceID,
 		Location:   &location,
 		Tags:       nil,
 		Properties: properties,
@@ -182,6 +184,7 @@ func TestMapFromVMScaleSetVMWithEmptyTags(t *testing.T) {
 		Tags:              map[string]*string{},
 		NetworkInterfaces: []string{},
 		ScaleSet:          scaleSet,
+		InstanceID:        instanceID,
 		Size:              size,
 	}
 
@@ -197,6 +200,7 @@ func TestMapFromVMScaleSetVMWithTags(t *testing.T) {
 	vmSize := armcompute.VirtualMachineSizeTypes(size)
 	osType := armcompute.OperatingSystemTypesLinux
 	vmType := "type"
+	instanceID := "123"
 	location := "westeurope"
 	computerName := "computer_name"
 	tags := map[string]*string{
@@ -224,6 +228,7 @@ func TestMapFromVMScaleSetVMWithTags(t *testing.T) {
 		ID:         &id,
 		Name:       &name,
 		Type:       &vmType,
+		InstanceID: &instanceID,
 		Location:   &location,
 		Tags:       tags,
 		Properties: properties,
@@ -240,6 +245,7 @@ func TestMapFromVMScaleSetVMWithTags(t *testing.T) {
 		Tags:              tags,
 		NetworkInterfaces: []string{},
 		ScaleSet:          scaleSet,
+		InstanceID:        instanceID,
 		Size:              size,
 	}
 
@@ -269,7 +275,7 @@ func TestNewAzureResourceFromID(t *testing.T) {
 		},
 	} {
 		actual, err := newAzureResourceFromID(tc.id, nil)
-		require.Nil(t, err)
+		require.NoError(t, err)
 		require.Equal(t, tc.expected.Name, actual.Name)
 		require.Equal(t, tc.expected.ResourceGroupName, actual.ResourceGroupName)
 	}

discovery/consul/consul.go

@@ -71,41 +71,18 @@ const (
 	namespace = "prometheus"
 )
 
-var (
-	rpcFailuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Namespace: namespace,
-			Name:      "sd_consul_rpc_failures_total",
-			Help:      "The number of Consul RPC call failures.",
-		})
-	rpcDuration = prometheus.NewSummaryVec(
-		prometheus.SummaryOpts{
-			Namespace:  namespace,
-			Name:       "sd_consul_rpc_duration_seconds",
-			Help:       "The duration of a Consul RPC call in seconds.",
-			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
-		},
-		[]string{"endpoint", "call"},
-	)
-
-	// Initialize metric vectors.
-	servicesRPCDuration = rpcDuration.WithLabelValues("catalog", "services")
-	serviceRPCDuration  = rpcDuration.WithLabelValues("catalog", "service")
-
-	// DefaultSDConfig is the default Consul SD configuration.
-	DefaultSDConfig = SDConfig{
-		TagSeparator:     ",",
-		Scheme:           "http",
-		Server:           "localhost:8500",
-		AllowStale:       true,
-		RefreshInterval:  model.Duration(30 * time.Second),
-		HTTPClientConfig: config.DefaultHTTPClientConfig,
-	}
-)
+// DefaultSDConfig is the default Consul SD configuration.
+var DefaultSDConfig = SDConfig{
+	TagSeparator:     ",",
+	Scheme:           "http",
+	Server:           "localhost:8500",
+	AllowStale:       true,
+	RefreshInterval:  model.Duration(30 * time.Second),
+	HTTPClientConfig: config.DefaultHTTPClientConfig,
+}
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(rpcFailuresCount, rpcDuration)
 }
 
 // SDConfig is the configuration for Consul service discovery.
@@ -147,7 +124,7 @@ func (*SDConfig) Name() string { return "consul" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -184,22 +161,27 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 // Discovery retrieves target information from a Consul server
 // and updates them via watches.
 type Discovery struct {
-	client           *consul.Client
-	clientDatacenter string
-	clientNamespace  string
-	clientPartition  string
-	tagSeparator     string
-	watchedServices  []string // Set of services which will be discovered.
-	watchedTags      []string // Tags used to filter instances of a service.
-	watchedNodeMeta  map[string]string
-	allowStale       bool
-	refreshInterval  time.Duration
-	finalizer        func()
-	logger           log.Logger
+	client              *consul.Client
+	clientDatacenter    string
+	clientNamespace     string
+	clientPartition     string
+	tagSeparator        string
+	watchedServices     []string // Set of services which will be discovered.
+	watchedTags         []string // Tags used to filter instances of a service.
+	watchedNodeMeta     map[string]string
+	allowStale          bool
+	refreshInterval     time.Duration
+	finalizer           func()
+	logger              log.Logger
+	rpcFailuresCount    prometheus.Counter
+	rpcDuration         *prometheus.SummaryVec
+	servicesRPCDuration prometheus.Observer
+	serviceRPCDuration  prometheus.Observer
+	metricRegisterer    discovery.MetricRegisterer
 }
 
 // NewDiscovery returns a new Discovery for the given config.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -237,7 +219,35 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 		clientPartition:  conf.Partition,
 		finalizer:        wrapper.CloseIdleConnections,
 		logger:           logger,
+		rpcFailuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Namespace: namespace,
+				Name:      "sd_consul_rpc_failures_total",
+				Help:      "The number of Consul RPC call failures.",
+			}),
+		rpcDuration: prometheus.NewSummaryVec(
+			prometheus.SummaryOpts{
+				Namespace:  namespace,
+				Name:       "sd_consul_rpc_duration_seconds",
+				Help:       "The duration of a Consul RPC call in seconds.",
+				Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+			},
+			[]string{"endpoint", "call"},
+		),
 	}
+
+	cd.metricRegisterer = discovery.NewMetricRegisterer(
+		reg,
+		[]prometheus.Collector{
+			cd.rpcFailuresCount,
+			cd.rpcDuration,
+		},
+	)
+
+	// Initialize metric vectors.
+	cd.servicesRPCDuration = cd.rpcDuration.WithLabelValues("catalog", "services")
+	cd.serviceRPCDuration = cd.rpcDuration.WithLabelValues("catalog", "service")
+
 	return cd, nil
 }
 
@@ -293,7 +303,7 @@ func (d *Discovery) getDatacenter() error {
 	info, err := d.client.Agent().Self()
 	if err != nil {
 		level.Error(d.logger).Log("msg", "Error retrieving datacenter name", "err", err)
-		rpcFailuresCount.Inc()
+		d.rpcFailuresCount.Inc()
 		return err
 	}
 
@@ -334,6 +344,13 @@ func (d *Discovery) initialize(ctx context.Context) {
 
 // Run implements the Discoverer interface.
 func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
+	err := d.metricRegisterer.RegisterMetrics()
+	if err != nil {
+		level.Error(d.logger).Log("msg", "Unable to register metrics", "err", err.Error())
+		return
+	}
+	defer d.metricRegisterer.UnregisterMetrics()
+
 	if d.finalizer != nil {
 		defer d.finalizer()
 	}
@@ -382,7 +399,7 @@ func (d *Discovery) watchServices(ctx context.Context, ch chan<- []*targetgroup.
 	t0 := time.Now()
 	srvs, meta, err := catalog.Services(opts.WithContext(ctx))
 	elapsed := time.Since(t0)
-	servicesRPCDuration.Observe(elapsed.Seconds())
+	d.servicesRPCDuration.Observe(elapsed.Seconds())
 
 	// Check the context before in order to exit early.
 	select {
@@ -393,7 +410,7 @@ func (d *Discovery) watchServices(ctx context.Context, ch chan<- []*targetgroup.
 
 	if err != nil {
 		level.Error(d.logger).Log("msg", "Error refreshing service list", "err", err)
-		rpcFailuresCount.Inc()
+		d.rpcFailuresCount.Inc()
 		time.Sleep(retryInterval)
 		return
 	}
@@ -449,13 +466,15 @@ func (d *Discovery) watchServices(ctx context.Context, ch chan<- []*targetgroup.
 
 // consulService contains data belonging to the same service.
 type consulService struct {
-	name         string
-	tags         []string
-	labels       model.LabelSet
-	discovery    *Discovery
-	client       *consul.Client
-	tagSeparator string
-	logger       log.Logger
+	name               string
+	tags               []string
+	labels             model.LabelSet
+	discovery          *Discovery
+	client             *consul.Client
+	tagSeparator       string
+	logger             log.Logger
+	rpcFailuresCount   prometheus.Counter
+	serviceRPCDuration prometheus.Observer
 }
 
 // Start watching a service.
@@ -469,8 +488,10 @@ func (d *Discovery) watchService(ctx context.Context, ch chan<- []*targetgroup.G
 			serviceLabel:    model.LabelValue(name),
 			datacenterLabel: model.LabelValue(d.clientDatacenter),
 		},
-		tagSeparator: d.tagSeparator,
-		logger:       d.logger,
+		tagSeparator:       d.tagSeparator,
+		logger:             d.logger,
+		rpcFailuresCount:   d.rpcFailuresCount,
+		serviceRPCDuration: d.serviceRPCDuration,
 	}
 
 	go func() {
@@ -508,7 +529,7 @@ func (srv *consulService) watch(ctx context.Context, ch chan<- []*targetgroup.Gr
 	t0 := time.Now()
 	serviceNodes, meta, err := health.ServiceMultipleTags(srv.name, srv.tags, false, opts.WithContext(ctx))
 	elapsed := time.Since(t0)
-	serviceRPCDuration.Observe(elapsed.Seconds())
+	srv.serviceRPCDuration.Observe(elapsed.Seconds())
 
 	// Check the context before in order to exit early.
 	select {
@@ -520,7 +541,7 @@ func (srv *consulService) watch(ctx context.Context, ch chan<- []*targetgroup.Gr
 
 	if err != nil {
 		level.Error(srv.logger).Log("msg", "Error refreshing service", "service", srv.name, "tags", strings.Join(srv.tags, ","), "err", err)
-		rpcFailuresCount.Inc()
+		srv.rpcFailuresCount.Inc()
 		time.Sleep(retryInterval)
 		return
 	}

discovery/consul/consul_test.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
@@ -39,7 +40,7 @@ func TestConfiguredService(t *testing.T) {
 	conf := &SDConfig{
 		Services: []string{"configuredServiceName"},
 	}
-	consulDiscovery, err := NewDiscovery(conf, nil)
+	consulDiscovery, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
 	if err != nil {
 		t.Errorf("Unexpected error when initializing discovery %v", err)
 	}
@@ -56,7 +57,7 @@ func TestConfiguredServiceWithTag(t *testing.T) {
 		Services:    []string{"configuredServiceName"},
 		ServiceTags: []string{"http"},
 	}
-	consulDiscovery, err := NewDiscovery(conf, nil)
+	consulDiscovery, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
 	if err != nil {
 		t.Errorf("Unexpected error when initializing discovery %v", err)
 	}
@@ -151,7 +152,7 @@ func TestConfiguredServiceWithTags(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		consulDiscovery, err := NewDiscovery(tc.conf, nil)
+		consulDiscovery, err := NewDiscovery(tc.conf, nil, prometheus.NewRegistry())
 		if err != nil {
 			t.Errorf("Unexpected error when initializing discovery %v", err)
 		}
@@ -165,7 +166,7 @@ func TestConfiguredServiceWithTags(t *testing.T) {
 
 func TestNonConfiguredService(t *testing.T) {
 	conf := &SDConfig{}
-	consulDiscovery, err := NewDiscovery(conf, nil)
+	consulDiscovery, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
 	if err != nil {
 		t.Errorf("Unexpected error when initializing discovery %v", err)
 	}
@@ -262,19 +263,19 @@ func newServer(t *testing.T) (*httptest.Server, *SDConfig) {
 
 func newDiscovery(t *testing.T, config *SDConfig) *Discovery {
 	logger := log.NewNopLogger()
-	d, err := NewDiscovery(config, logger)
+	d, err := NewDiscovery(config, logger, prometheus.NewRegistry())
 	require.NoError(t, err)
 	return d
 }
 
 func checkOneTarget(t *testing.T, tg []*targetgroup.Group) {
-	require.Equal(t, 1, len(tg))
+	require.Len(t, tg, 1)
 	target := tg[0]
 	require.Equal(t, "test-dc", string(target.Labels["__meta_consul_dc"]))
 	require.Equal(t, target.Source, string(target.Labels["__meta_consul_service"]))
 	if target.Source == "test" {
 		// test service should have one node.
-		require.Greater(t, len(target.Targets), 0, "Test service should have one node")
+		require.NotEmpty(t, target.Targets, "Test service should have one node")
 	}
 }
 
@@ -313,7 +314,7 @@ func TestNoTargets(t *testing.T) {
 	}()
 
 	targets := (<-ch)[0].Targets
-	require.Equal(t, 0, len(targets))
+	require.Empty(t, targets)
 	cancel()
 	<-ch
 }
@@ -484,7 +485,7 @@ oauth2:
 				return
 			}
 
-			require.Equal(t, config, test.expected)
+			require.Equal(t, test.expected, config)
 		})
 	}
 }

discovery/digitalocean/digitalocean.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/digitalocean/godo"
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/version"
@@ -75,7 +76,7 @@ func (*SDConfig) Name() string { return "digitalocean" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -103,7 +104,7 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	d := &Discovery{
 		port: conf.Port,
 	}
@@ -125,10 +126,13 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"digitalocean",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "digitalocean",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/digitalocean/digitalocean_test.go

@@ -20,6 +20,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 )
@@ -46,7 +47,7 @@ func TestDigitalOceanSDRefresh(t *testing.T) {
 
 	cfg := DefaultSDConfig
 	cfg.HTTPClientConfig.BearerToken = tokenID
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 	endpoint, err := url.Parse(sdmock.Mock.Endpoint())
 	require.NoError(t, err)
@@ -56,12 +57,12 @@ func TestDigitalOceanSDRefresh(t *testing.T) {
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 4, len(tg.Targets))
+	require.Len(t, tg.Targets, 4)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/discovery.go

@@ -18,6 +18,7 @@ import (
 	"reflect"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 
 	"github.com/prometheus/prometheus/discovery/targetgroup"
@@ -42,6 +43,15 @@ type Discoverer interface {
 type DiscovererOptions struct {
 	Logger log.Logger
 
+	// A registerer for the Discoverer's metrics.
+	// Some Discoverers may ignore this registerer and use the global one instead.
+	// For now this will work, because the Prometheus `main` function uses the global registry.
+	// However, in the future the Prometheus `main` function will be updated to not use the global registry.
+	// Hence, if a discoverer wants its metrics to be visible via the Prometheus executable's
+	// `/metrics` endpoint, it should use this explicit registerer.
+	// TODO(ptodev): Update this comment once the Prometheus `main` function does not use the global registry.
+	Registerer prometheus.Registerer
+
 	// Extra HTTP client options to expose to Discoverers. This field may be
 	// ignored; Discoverer implementations must opt-in to reading it.
 	HTTPClientOptions []config.HTTPClientOption

discovery/dns/dns.go

@@ -42,35 +42,21 @@ const (
 	dnsSrvRecordPortLabel   = dnsSrvRecordPrefix + "port"
 	dnsMxRecordPrefix       = model.MetaLabelPrefix + "dns_mx_record_"
 	dnsMxRecordTargetLabel  = dnsMxRecordPrefix + "target"
+	dnsNsRecordPrefix       = model.MetaLabelPrefix + "dns_ns_record_"
+	dnsNsRecordTargetLabel  = dnsNsRecordPrefix + "target"
 
 	// Constants for instrumentation.
 	namespace = "prometheus"
 )
 
-var (
-	dnsSDLookupsCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Namespace: namespace,
-			Name:      "sd_dns_lookups_total",
-			Help:      "The number of DNS-SD lookups.",
-		})
-	dnsSDLookupFailuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Namespace: namespace,
-			Name:      "sd_dns_lookup_failures_total",
-			Help:      "The number of DNS-SD lookup failures.",
-		})
-
-	// DefaultSDConfig is the default DNS SD configuration.
-	DefaultSDConfig = SDConfig{
-		RefreshInterval: model.Duration(30 * time.Second),
-		Type:            "SRV",
-	}
-)
+// DefaultSDConfig is the default DNS SD configuration.
+var DefaultSDConfig = SDConfig{
+	RefreshInterval: model.Duration(30 * time.Second),
+	Type:            "SRV",
+}
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(dnsSDLookupFailuresCount, dnsSDLookupsCount)
 }
 
 // SDConfig is the configuration for DNS based service discovery.
@@ -86,7 +72,7 @@ func (*SDConfig) Name() string { return "dns" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(*c, opts.Logger), nil
+	return NewDiscovery(*c, opts.Logger, opts.Registerer)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
@@ -102,7 +88,7 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	}
 	switch strings.ToUpper(c.Type) {
 	case "SRV":
-	case "A", "AAAA", "MX":
+	case "A", "AAAA", "MX", "NS":
 		if c.Port == 0 {
 			return errors.New("a port is required in DNS-SD configs for all record types except SRV")
 		}
@@ -116,16 +102,18 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 // the Discoverer interface.
 type Discovery struct {
 	*refresh.Discovery
-	names  []string
-	port   int
-	qtype  uint16
-	logger log.Logger
+	names                    []string
+	port                     int
+	qtype                    uint16
+	logger                   log.Logger
+	dnsSDLookupsCount        prometheus.Counter
+	dnsSDLookupFailuresCount prometheus.Counter
 
 	lookupFn func(name string, qtype uint16, logger log.Logger) (*dns.Msg, error)
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf SDConfig, logger log.Logger) *Discovery {
+func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -140,6 +128,8 @@ func NewDiscovery(conf SDConfig, logger log.Logger) *Discovery {
 		qtype = dns.TypeSRV
 	case "MX":
 		qtype = dns.TypeMX
+	case "NS":
+		qtype = dns.TypeNS
 	}
 	d := &Discovery{
 		names:    conf.Names,
@@ -147,14 +137,32 @@ func NewDiscovery(conf SDConfig, logger log.Logger) *Discovery {
 		port:     conf.Port,
 		logger:   logger,
 		lookupFn: lookupWithSearchPath,
+		dnsSDLookupsCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Namespace: namespace,
+				Name:      "sd_dns_lookups_total",
+				Help:      "The number of DNS-SD lookups.",
+			}),
+		dnsSDLookupFailuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Namespace: namespace,
+				Name:      "sd_dns_lookup_failures_total",
+				Help:      "The number of DNS-SD lookup failures.",
+			}),
 	}
+
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"dns",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "dns",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: prometheus.NewRegistry(),
+			Metrics:  []prometheus.Collector{d.dnsSDLookupsCount, d.dnsSDLookupFailuresCount},
+		},
 	)
-	return d
+
+	return d, nil
 }
 
 func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
@@ -187,9 +195,9 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 
 func (d *Discovery) refreshOne(ctx context.Context, name string, ch chan<- *targetgroup.Group) error {
 	response, err := d.lookupFn(name, d.qtype, d.logger)
-	dnsSDLookupsCount.Inc()
+	d.dnsSDLookupsCount.Inc()
 	if err != nil {
-		dnsSDLookupFailuresCount.Inc()
+		d.dnsSDLookupFailuresCount.Inc()
 		return err
 	}
 
@@ -199,7 +207,7 @@ func (d *Discovery) refreshOne(ctx context.Context, name string, ch chan<- *targ
 	}
 
 	for _, record := range response.Answer {
-		var target, dnsSrvRecordTarget, dnsSrvRecordPort, dnsMxRecordTarget model.LabelValue
+		var target, dnsSrvRecordTarget, dnsSrvRecordPort, dnsMxRecordTarget, dnsNsRecordTarget model.LabelValue
 
 		switch addr := record.(type) {
 		case *dns.SRV:
@@ -217,6 +225,13 @@ func (d *Discovery) refreshOne(ctx context.Context, name string, ch chan<- *targ
 			addr.Mx = strings.TrimRight(addr.Mx, ".")
 
 			target = hostPort(addr.Mx, d.port)
+		case *dns.NS:
+			dnsNsRecordTarget = model.LabelValue(addr.Ns)
+
+			// Remove the final dot from rooted DNS names to make them look more usual.
+			addr.Ns = strings.TrimRight(addr.Ns, ".")
+
+			target = hostPort(addr.Ns, d.port)
 		case *dns.A:
 			target = hostPort(addr.A.String(), d.port)
 		case *dns.AAAA:
@@ -234,6 +249,7 @@ func (d *Discovery) refreshOne(ctx context.Context, name string, ch chan<- *targ
 			dnsSrvRecordTargetLabel: dnsSrvRecordTarget,
 			dnsSrvRecordPortLabel:   dnsSrvRecordPort,
 			dnsMxRecordTargetLabel:  dnsMxRecordTarget,
+			dnsNsRecordTargetLabel:  dnsNsRecordTarget,
 		})
 	}
 

discovery/dns/dns_test.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/miekg/dns"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
@@ -81,6 +82,7 @@ func TestDNS(t *testing.T) {
 							"__meta_dns_srv_record_target": "",
 							"__meta_dns_srv_record_port":   "",
 							"__meta_dns_mx_record_target":  "",
+							"__meta_dns_ns_record_target":  "",
 						},
 					},
 				},
@@ -112,6 +114,7 @@ func TestDNS(t *testing.T) {
 							"__meta_dns_srv_record_target": "",
 							"__meta_dns_srv_record_port":   "",
 							"__meta_dns_mx_record_target":  "",
+							"__meta_dns_ns_record_target":  "",
 						},
 					},
 				},
@@ -143,6 +146,7 @@ func TestDNS(t *testing.T) {
 							"__meta_dns_srv_record_target": "db1.example.com.",
 							"__meta_dns_srv_record_port":   "3306",
 							"__meta_dns_mx_record_target":  "",
+							"__meta_dns_ns_record_target":  "",
 						},
 						{
 							"__address__":                  "db2.example.com:3306",
@@ -150,6 +154,7 @@ func TestDNS(t *testing.T) {
 							"__meta_dns_srv_record_target": "db2.example.com.",
 							"__meta_dns_srv_record_port":   "3306",
 							"__meta_dns_mx_record_target":  "",
+							"__meta_dns_ns_record_target":  "",
 						},
 					},
 				},
@@ -180,6 +185,7 @@ func TestDNS(t *testing.T) {
 							"__meta_dns_srv_record_target": "db1.example.com.",
 							"__meta_dns_srv_record_port":   "3306",
 							"__meta_dns_mx_record_target":  "",
+							"__meta_dns_ns_record_target":  "",
 						},
 					},
 				},
@@ -227,6 +233,7 @@ func TestDNS(t *testing.T) {
 							"__meta_dns_srv_record_target": "",
 							"__meta_dns_srv_record_port":   "",
 							"__meta_dns_mx_record_target":  "smtp1.example.com.",
+							"__meta_dns_ns_record_target":  "",
 						},
 						{
 							"__address__":                  "smtp2.example.com:25",
@@ -234,6 +241,7 @@ func TestDNS(t *testing.T) {
 							"__meta_dns_srv_record_target": "",
 							"__meta_dns_srv_record_port":   "",
 							"__meta_dns_mx_record_target":  "smtp2.example.com.",
+							"__meta_dns_ns_record_target":  "",
 						},
 					},
 				},
@@ -245,7 +253,8 @@ func TestDNS(t *testing.T) {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
-			sd := NewDiscovery(tc.config, nil)
+			sd, err := NewDiscovery(tc.config, nil, prometheus.NewRegistry())
+			require.NoError(t, err)
 			sd.lookupFn = tc.lookup
 
 			tgs, err := sd.refresh(context.Background())

discovery/eureka/client_test.go

@@ -184,17 +184,17 @@ func TestFetchApps(t *testing.T) {
 	apps, err := fetchApps(context.TODO(), ts.URL, &http.Client{})
 	require.NoError(t, err)
 
-	require.Equal(t, len(apps.Applications), 2)
-	require.Equal(t, apps.Applications[0].Name, "CONFIG-SERVICE")
-	require.Equal(t, apps.Applications[1].Name, "META-SERVICE")
+	require.Len(t, apps.Applications, 2)
+	require.Equal(t, "CONFIG-SERVICE", apps.Applications[0].Name)
+	require.Equal(t, "META-SERVICE", apps.Applications[1].Name)
 
-	require.Equal(t, len(apps.Applications[1].Instances), 2)
-	require.Equal(t, apps.Applications[1].Instances[0].InstanceID, "meta-service002.test.com:meta-service:8080")
-	require.Equal(t, apps.Applications[1].Instances[0].Metadata.Items[0].XMLName.Local, "project")
-	require.Equal(t, apps.Applications[1].Instances[0].Metadata.Items[0].Content, "meta-service")
-	require.Equal(t, apps.Applications[1].Instances[0].Metadata.Items[1].XMLName.Local, "management.port")
-	require.Equal(t, apps.Applications[1].Instances[0].Metadata.Items[1].Content, "8090")
-	require.Equal(t, apps.Applications[1].Instances[1].InstanceID, "meta-service001.test.com:meta-service:8080")
+	require.Len(t, apps.Applications[1].Instances, 2)
+	require.Equal(t, "meta-service002.test.com:meta-service:8080", apps.Applications[1].Instances[0].InstanceID)
+	require.Equal(t, "project", apps.Applications[1].Instances[0].Metadata.Items[0].XMLName.Local)
+	require.Equal(t, "meta-service", apps.Applications[1].Instances[0].Metadata.Items[0].Content)
+	require.Equal(t, "management.port", apps.Applications[1].Instances[0].Metadata.Items[1].XMLName.Local)
+	require.Equal(t, "8090", apps.Applications[1].Instances[0].Metadata.Items[1].Content)
+	require.Equal(t, "meta-service001.test.com:meta-service:8080", apps.Applications[1].Instances[1].InstanceID)
 }
 
 func Test500ErrorHttpResponse(t *testing.T) {

discovery/eureka/eureka.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -80,7 +81,7 @@ func (*SDConfig) Name() string { return "eureka" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -117,7 +118,7 @@ type Discovery struct {
 }
 
 // NewDiscovery creates a new Eureka discovery for the given role.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "eureka_sd")
 	if err != nil {
 		return nil, err
@@ -128,10 +129,13 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 		server: conf.Server,
 	}
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"eureka",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "eureka",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/eureka/eureka_test.go

@@ -20,6 +20,7 @@ import (
 	"net/http/httptest"
 	"testing"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 
@@ -35,7 +36,7 @@ func testUpdateServices(respHandler http.HandlerFunc) ([]*targetgroup.Group, err
 		Server: ts.URL,
 	}
 
-	md, err := NewDiscovery(&conf, nil)
+	md, err := NewDiscovery(&conf, nil, prometheus.NewRegistry())
 	if err != nil {
 		return nil, err
 	}
@@ -55,7 +56,7 @@ func TestEurekaSDHandleError(t *testing.T) {
 	tgs, err := testUpdateServices(respHandler)
 
 	require.EqualError(t, err, errTesting)
-	require.Equal(t, len(tgs), 0)
+	require.Empty(t, tgs)
 }
 
 func TestEurekaSDEmptyList(t *testing.T) {
@@ -72,7 +73,7 @@ func TestEurekaSDEmptyList(t *testing.T) {
 	)
 	tgs, err := testUpdateServices(respHandler)
 	require.NoError(t, err)
-	require.Equal(t, len(tgs), 1)
+	require.Len(t, tgs, 1)
 }
 
 func TestEurekaSDSendGroup(t *testing.T) {
@@ -232,11 +233,11 @@ func TestEurekaSDSendGroup(t *testing.T) {
 
 	tgs, err := testUpdateServices(respHandler)
 	require.NoError(t, err)
-	require.Equal(t, len(tgs), 1)
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
-	require.Equal(t, tg.Source, "eureka")
-	require.Equal(t, len(tg.Targets), 4)
+	require.Equal(t, "eureka", tg.Source)
+	require.Len(t, tg.Targets, 4)
 
 	tgt := tg.Targets[0]
 	require.Equal(t, tgt[model.AddressLabel], model.LabelValue("config-service001.test.com:8080"))

discovery/file/file.go

@@ -39,24 +39,6 @@ import (
 )
 
 var (
-	fileSDReadErrorsCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_file_read_errors_total",
-			Help: "The number of File-SD read errors.",
-		})
-	fileSDScanDuration = prometheus.NewSummary(
-		prometheus.SummaryOpts{
-			Name:       "prometheus_sd_file_scan_duration_seconds",
-			Help:       "The duration of the File-SD scan in seconds.",
-			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
-		})
-	fileSDTimeStamp        = NewTimestampCollector()
-	fileWatcherErrorsCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_file_watcher_errors_total",
-			Help: "The number of File-SD errors caused by filesystem watch failures.",
-		})
-
 	patFileSDName = regexp.MustCompile(`^[^*]*(\*[^/]*)?\.(json|yml|yaml|JSON|YML|YAML)$`)
 
 	// DefaultSDConfig is the default file SD configuration.
@@ -67,7 +49,6 @@ var (
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(fileSDReadErrorsCount, fileSDScanDuration, fileSDTimeStamp, fileWatcherErrorsCount)
 }
 
 // SDConfig is the configuration for file based discovery.
@@ -81,7 +62,7 @@ func (*SDConfig) Name() string { return "file" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger), nil
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -187,10 +168,17 @@ type Discovery struct {
 	// This is used to detect deleted target groups.
 	lastRefresh map[string]int
 	logger      log.Logger
+
+	fileSDReadErrorsCount  prometheus.Counter
+	fileSDScanDuration     prometheus.Summary
+	fileWatcherErrorsCount prometheus.Counter
+	fileSDTimeStamp        *TimestampCollector
+
+	metricRegisterer discovery.MetricRegisterer
 }
 
 // NewDiscovery returns a new file discovery for the given paths.
-func NewDiscovery(conf *SDConfig, logger log.Logger) *Discovery {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -200,9 +188,35 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) *Discovery {
 		interval:   time.Duration(conf.RefreshInterval),
 		timestamps: make(map[string]float64),
 		logger:     logger,
+		fileSDReadErrorsCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_file_read_errors_total",
+				Help: "The number of File-SD read errors.",
+			}),
+		fileSDScanDuration: prometheus.NewSummary(
+			prometheus.SummaryOpts{
+				Name:       "prometheus_sd_file_scan_duration_seconds",
+				Help:       "The duration of the File-SD scan in seconds.",
+				Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+			}),
+		fileWatcherErrorsCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_file_watcher_errors_total",
+				Help: "The number of File-SD errors caused by filesystem watch failures.",
+			}),
+		fileSDTimeStamp: NewTimestampCollector(),
 	}
-	fileSDTimeStamp.addDiscoverer(disc)
-	return disc
+
+	disc.fileSDTimeStamp.addDiscoverer(disc)
+
+	disc.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		disc.fileSDReadErrorsCount,
+		disc.fileSDScanDuration,
+		disc.fileWatcherErrorsCount,
+		disc.fileSDTimeStamp,
+	})
+
+	return disc, nil
 }
 
 // listFiles returns a list of all files that match the configured patterns.
@@ -239,10 +253,17 @@ func (d *Discovery) watchFiles() {
 
 // Run implements the Discoverer interface.
 func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
+	err := d.metricRegisterer.RegisterMetrics()
+	if err != nil {
+		level.Error(d.logger).Log("msg", "Unable to register metrics", "err", err.Error())
+		return
+	}
+	defer d.metricRegisterer.UnregisterMetrics()
+
 	watcher, err := fsnotify.NewWatcher()
 	if err != nil {
 		level.Error(d.logger).Log("msg", "Error adding file watcher", "err", err)
-		fileWatcherErrorsCount.Inc()
+		d.fileWatcherErrorsCount.Inc()
 		return
 	}
 	d.watcher = watcher
@@ -306,7 +327,7 @@ func (d *Discovery) stop() {
 	done := make(chan struct{})
 	defer close(done)
 
-	fileSDTimeStamp.removeDiscoverer(d)
+	d.fileSDTimeStamp.removeDiscoverer(d)
 
 	// Closing the watcher will deadlock unless all events and errors are drained.
 	go func() {
@@ -332,13 +353,13 @@ func (d *Discovery) stop() {
 func (d *Discovery) refresh(ctx context.Context, ch chan<- []*targetgroup.Group) {
 	t0 := time.Now()
 	defer func() {
-		fileSDScanDuration.Observe(time.Since(t0).Seconds())
+		d.fileSDScanDuration.Observe(time.Since(t0).Seconds())
 	}()
 	ref := map[string]int{}
 	for _, p := range d.listFiles() {
 		tgroups, err := d.readFile(p)
 		if err != nil {
-			fileSDReadErrorsCount.Inc()
+			d.fileSDReadErrorsCount.Inc()
 
 			level.Error(d.logger).Log("msg", "Error reading file", "path", p, "err", err)
 			// Prevent deletion down below.

discovery/file/file_test.go

@@ -24,6 +24,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
@@ -143,7 +144,7 @@ func (t *testRunner) run(files ...string) {
 	ctx, cancel := context.WithCancel(context.Background())
 	t.cancelSD = cancel
 	go func() {
-		NewDiscovery(
+		d, err := NewDiscovery(
 			&SDConfig{
 				Files: files,
 				// Setting a high refresh interval to make sure that the tests only
@@ -151,7 +152,11 @@ func (t *testRunner) run(files ...string) {
 				RefreshInterval: model.Duration(1 * time.Hour),
 			},
 			nil,
-		).Run(ctx, t.ch)
+			prometheus.NewRegistry(),
+		)
+		require.NoError(t, err)
+
+		d.Run(ctx, t.ch)
 	}()
 }
 

discovery/gce/gce.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/compute/v1"
@@ -86,7 +87,7 @@ func (*SDConfig) Name() string { return "gce" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(*c, opts.Logger)
+	return NewDiscovery(*c, opts.Logger, opts.Registerer)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
@@ -121,7 +122,7 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	d := &Discovery{
 		project:      conf.Project,
 		zone:         conf.Zone,
@@ -141,10 +142,13 @@ func NewDiscovery(conf SDConfig, logger log.Logger) (*Discovery, error) {
 	d.isvc = compute.NewInstancesService(d.svc)
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"gce",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "gce",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/hetzner/hcloud_test.go

@@ -48,12 +48,12 @@ func TestHCloudSDRefresh(t *testing.T) {
 
 	targetGroups, err := d.refresh(context.Background())
 	require.NoError(t, err)
-	require.Equal(t, 1, len(targetGroups))
+	require.Len(t, targetGroups, 1)
 
 	targetGroup := targetGroups[0]
 	require.NotNil(t, targetGroup, "targetGroup should not be nil")
 	require.NotNil(t, targetGroup.Targets, "targetGroup.targets should not be nil")
-	require.Equal(t, 3, len(targetGroup.Targets))
+	require.Len(t, targetGroup.Targets, 3)
 
 	for i, labelSet := range []model.LabelSet{
 		{

discovery/hetzner/hetzner.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/hetznercloud/hcloud-go/v2/hcloud"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -67,7 +68,7 @@ func (*SDConfig) Name() string { return "hetzner" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 type refresher interface {
@@ -127,17 +128,20 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
 	r, err := newRefresher(conf, logger)
 	if err != nil {
 		return nil, err
 	}
 
 	return refresh.NewDiscovery(
-		logger,
-		"hetzner",
-		time.Duration(conf.RefreshInterval),
-		r.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "hetzner",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: r.refresh,
+			Registry: reg,
+		},
 	), nil
 }
 

discovery/hetzner/robot_test.go

@@ -47,12 +47,12 @@ func TestRobotSDRefresh(t *testing.T) {
 
 	targetGroups, err := d.refresh(context.Background())
 	require.NoError(t, err)
-	require.Equal(t, 1, len(targetGroups))
+	require.Len(t, targetGroups, 1)
 
 	targetGroup := targetGroups[0]
 	require.NotNil(t, targetGroup, "targetGroup should not be nil")
 	require.NotNil(t, targetGroup.Targets, "targetGroup.targets should not be nil")
-	require.Equal(t, 2, len(targetGroup.Targets))
+	require.Len(t, targetGroup.Targets, 2)
 
 	for i, labelSet := range []model.LabelSet{
 		{
@@ -98,5 +98,5 @@ func TestRobotSDRefreshHandleError(t *testing.T) {
 	require.Error(t, err)
 	require.Equal(t, "non 2xx status '401' response during hetzner service discovery with role robot", err.Error())
 
-	require.Equal(t, 0, len(targetGroups))
+	require.Empty(t, targetGroups)
 }

discovery/http/http.go

@@ -45,17 +45,10 @@ var (
 	}
 	userAgent        = fmt.Sprintf("Prometheus/%s", version.Version)
 	matchContentType = regexp.MustCompile(`^(?i:application\/json(;\s*charset=("utf-8"|utf-8))?)$`)
-
-	failuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_http_failures_total",
-			Help: "Number of HTTP service discovery refresh failures.",
-		})
 )
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(failuresCount)
 }
 
 // SDConfig is the configuration for HTTP based discovery.
@@ -70,7 +63,7 @@ func (*SDConfig) Name() string { return "http" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger, opts.HTTPClientOptions)
+	return NewDiscovery(c, opts.Logger, opts.HTTPClientOptions, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -112,10 +105,11 @@ type Discovery struct {
 	client          *http.Client
 	refreshInterval time.Duration
 	tgLastLength    int
+	failuresCount   prometheus.Counter
 }
 
 // NewDiscovery returns a new HTTP discovery for the given config.
-func NewDiscovery(conf *SDConfig, logger log.Logger, clientOpts []config.HTTPClientOption) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, clientOpts []config.HTTPClientOption, reg prometheus.Registerer) (*Discovery, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -130,13 +124,22 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, clientOpts []config.HTTPCli
 		url:             conf.URL,
 		client:          client,
 		refreshInterval: time.Duration(conf.RefreshInterval), // Stored to be sent as headers.
+		failuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_http_failures_total",
+				Help: "Number of HTTP service discovery refresh failures.",
+			}),
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"http",
-		time.Duration(conf.RefreshInterval),
-		d.Refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "http",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.Refresh,
+			Registry: reg,
+			Metrics:  []prometheus.Collector{d.failuresCount},
+		},
 	)
 	return d, nil
 }
@@ -152,7 +155,7 @@ func (d *Discovery) Refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 
 	resp, err := d.client.Do(req.WithContext(ctx))
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, err
 	}
 	defer func() {
@@ -161,31 +164,31 @@ func (d *Discovery) Refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 	}()
 
 	if resp.StatusCode != http.StatusOK {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, fmt.Errorf("server returned HTTP status %s", resp.Status)
 	}
 
 	if !matchContentType.MatchString(strings.TrimSpace(resp.Header.Get("Content-Type"))) {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, fmt.Errorf("unsupported content type %q", resp.Header.Get("Content-Type"))
 	}
 
 	b, err := io.ReadAll(resp.Body)
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, err
 	}
 
 	var targetGroups []*targetgroup.Group
 
 	if err := json.Unmarshal(b, &targetGroups); err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, err
 	}
 
 	for i, tg := range targetGroups {
 		if tg == nil {
-			failuresCount.Inc()
+			d.failuresCount.Inc()
 			err = errors.New("nil target group item found")
 			return nil, err
 		}

discovery/http/http_test.go

@@ -41,7 +41,7 @@ func TestHTTPValidRefresh(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil)
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -62,8 +62,8 @@ func TestHTTPValidRefresh(t *testing.T) {
 			Source: urlSource(ts.URL+"/http_sd.good.json", 0),
 		},
 	}
-	require.Equal(t, tgs, expectedTargets)
-	require.Equal(t, 0.0, getFailureCount())
+	require.Equal(t, expectedTargets, tgs)
+	require.Equal(t, 0.0, getFailureCount(d.failuresCount))
 }
 
 func TestHTTPInvalidCode(t *testing.T) {
@@ -79,13 +79,13 @@ func TestHTTPInvalidCode(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil)
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	_, err = d.Refresh(ctx)
 	require.EqualError(t, err, "server returned HTTP status 400 Bad Request")
-	require.Equal(t, 1.0, getFailureCount())
+	require.Equal(t, 1.0, getFailureCount(d.failuresCount))
 }
 
 func TestHTTPInvalidFormat(t *testing.T) {
@@ -101,18 +101,16 @@ func TestHTTPInvalidFormat(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil)
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	_, err = d.Refresh(ctx)
 	require.EqualError(t, err, `unsupported content type "text/plain; charset=utf-8"`)
-	require.Equal(t, 1.0, getFailureCount())
+	require.Equal(t, 1.0, getFailureCount(d.failuresCount))
 }
 
-var lastFailureCount float64
-
-func getFailureCount() float64 {
+func getFailureCount(failuresCount prometheus.Counter) float64 {
 	failureChan := make(chan prometheus.Metric)
 
 	go func() {
@@ -129,10 +127,7 @@ func getFailureCount() float64 {
 		metric.Write(&counter)
 	}
 
-	// account for failures in prior tests
-	count := *counter.Counter.Value - lastFailureCount
-	lastFailureCount = *counter.Counter.Value
-	return count
+	return *counter.Counter.Value
 }
 
 func TestContentTypeRegex(t *testing.T) {
@@ -417,7 +412,7 @@ func TestSourceDisappeared(t *testing.T) {
 		URL:              ts.URL,
 		RefreshInterval:  model.Duration(1 * time.Second),
 	}
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil)
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
 	require.NoError(t, err)
 	for _, test := range cases {
 		ctx := context.Background()

discovery/ionos/ionos.go

@@ -23,6 +23,8 @@ import (
 
 	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/refresh"
+
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 const (
@@ -41,7 +43,7 @@ func init() {
 type Discovery struct{}
 
 // NewDiscovery returns a new refresh.Discovery for IONOS Cloud.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
 	if conf.ionosEndpoint == "" {
 		conf.ionosEndpoint = "https://api.ionos.com"
 	}
@@ -52,10 +54,13 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*refresh.Discovery, error)
 	}
 
 	return refresh.NewDiscovery(
-		logger,
-		"ionos",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "ionos",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	), nil
 }
 
@@ -86,7 +91,7 @@ func (c SDConfig) Name() string {
 
 // NewDiscoverer returns a new discovery.Discoverer for IONOS Cloud.
 func (c SDConfig) NewDiscoverer(options discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(&c, options.Logger)
+	return NewDiscovery(&c, options.Logger, options.Registerer)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.

discovery/ionos/server_test.go

@@ -48,12 +48,12 @@ func TestIONOSServerRefresh(t *testing.T) {
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 2, len(tg.Targets))
+	require.Len(t, tg.Targets, 2)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/kubernetes/endpoints.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	apiv1 "k8s.io/api/core/v1"
 	"k8s.io/client-go/tools/cache"
@@ -30,12 +31,6 @@ import (
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
-var (
-	epAddCount    = eventCount.WithLabelValues("endpoints", "add")
-	epUpdateCount = eventCount.WithLabelValues("endpoints", "update")
-	epDeleteCount = eventCount.WithLabelValues("endpoints", "delete")
-)
-
 // Endpoints discovers new endpoint targets.
 type Endpoints struct {
 	logger log.Logger
@@ -54,10 +49,19 @@ type Endpoints struct {
 }
 
 // NewEndpoints returns a new endpoints discovery.
-func NewEndpoints(l log.Logger, eps cache.SharedIndexInformer, svc, pod, node cache.SharedInformer) *Endpoints {
+func NewEndpoints(l log.Logger, eps cache.SharedIndexInformer, svc, pod, node cache.SharedInformer, eventCount *prometheus.CounterVec) *Endpoints {
 	if l == nil {
 		l = log.NewNopLogger()
 	}
+
+	epAddCount := eventCount.WithLabelValues(RoleEndpoint.String(), MetricLabelRoleAdd)
+	epUpdateCount := eventCount.WithLabelValues(RoleEndpoint.String(), MetricLabelRoleUpdate)
+	epDeleteCount := eventCount.WithLabelValues(RoleEndpoint.String(), MetricLabelRoleDelete)
+
+	svcAddCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleAdd)
+	svcUpdateCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleUpdate)
+	svcDeleteCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleDelete)
+
 	e := &Endpoints{
 		logger:           l,
 		endpointsInf:     eps,
@@ -68,7 +72,7 @@ func NewEndpoints(l log.Logger, eps cache.SharedIndexInformer, svc, pod, node ca
 		podStore:         pod.GetStore(),
 		nodeInf:          node,
 		withNodeMetadata: node != nil,
-		queue:            workqueue.NewNamed("endpoints"),
+		queue:            workqueue.NewNamed(RoleEndpoint.String()),
 	}
 
 	_, err := e.endpointsInf.AddEventHandler(cache.ResourceEventHandlerFuncs{

discovery/kubernetes/endpointslice.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	apiv1 "k8s.io/api/core/v1"
 	v1 "k8s.io/api/discovery/v1"
@@ -33,12 +34,6 @@ import (
 	"github.com/prometheus/prometheus/util/strutil"
 )
 
-var (
-	epslAddCount    = eventCount.WithLabelValues("endpointslice", "add")
-	epslUpdateCount = eventCount.WithLabelValues("endpointslice", "update")
-	epslDeleteCount = eventCount.WithLabelValues("endpointslice", "delete")
-)
-
 // EndpointSlice discovers new endpoint targets.
 type EndpointSlice struct {
 	logger log.Logger
@@ -57,10 +52,19 @@ type EndpointSlice struct {
 }
 
 // NewEndpointSlice returns a new endpointslice discovery.
-func NewEndpointSlice(l log.Logger, eps cache.SharedIndexInformer, svc, pod, node cache.SharedInformer) *EndpointSlice {
+func NewEndpointSlice(l log.Logger, eps cache.SharedIndexInformer, svc, pod, node cache.SharedInformer, eventCount *prometheus.CounterVec) *EndpointSlice {
 	if l == nil {
 		l = log.NewNopLogger()
 	}
+
+	epslAddCount := eventCount.WithLabelValues(RoleEndpointSlice.String(), MetricLabelRoleAdd)
+	epslUpdateCount := eventCount.WithLabelValues(RoleEndpointSlice.String(), MetricLabelRoleUpdate)
+	epslDeleteCount := eventCount.WithLabelValues(RoleEndpointSlice.String(), MetricLabelRoleDelete)
+
+	svcAddCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleAdd)
+	svcUpdateCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleUpdate)
+	svcDeleteCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleDelete)
+
 	e := &EndpointSlice{
 		logger:             l,
 		endpointSliceInf:   eps,
@@ -71,7 +75,7 @@ func NewEndpointSlice(l log.Logger, eps cache.SharedIndexInformer, svc, pod, nod
 		podStore:           pod.GetStore(),
 		nodeInf:            node,
 		withNodeMetadata:   node != nil,
-		queue:              workqueue.NewNamed("endpointSlice"),
+		queue:              workqueue.NewNamed(RoleEndpointSlice.String()),
 	}
 
 	_, err := e.endpointSliceInf.AddEventHandler(cache.ResourceEventHandlerFuncs{

discovery/kubernetes/endpointslice_adaptor_test.go

@@ -29,7 +29,7 @@ func Test_EndpointSliceAdaptor_v1(t *testing.T) {
 	require.Equal(t, endpointSlice.ObjectMeta.Namespace, adaptor.namespace())
 	require.Equal(t, endpointSlice.AddressType, v1.AddressType(adaptor.addressType()))
 	require.Equal(t, endpointSlice.Labels, adaptor.labels())
-	require.Equal(t, endpointSlice.Labels[v1.LabelServiceName], "testendpoints")
+	require.Equal(t, "testendpoints", endpointSlice.Labels[v1.LabelServiceName])
 
 	for i, endpointAdaptor := range adaptor.endpoints() {
 		require.Equal(t, endpointSlice.Endpoints[i].Addresses, endpointAdaptor.addresses())
@@ -57,7 +57,7 @@ func Test_EndpointSliceAdaptor_v1beta1(t *testing.T) {
 	require.Equal(t, endpointSlice.ObjectMeta.Namespace, adaptor.namespace())
 	require.Equal(t, endpointSlice.AddressType, v1beta1.AddressType(adaptor.addressType()))
 	require.Equal(t, endpointSlice.Labels, adaptor.labels())
-	require.Equal(t, endpointSlice.Labels[v1beta1.LabelServiceName], "testendpoints")
+	require.Equal(t, "testendpoints", endpointSlice.Labels[v1beta1.LabelServiceName])
 
 	for i, endpointAdaptor := range adaptor.endpoints() {
 		require.Equal(t, endpointSlice.Endpoints[i].Addresses, endpointAdaptor.addresses())

discovery/kubernetes/ingress.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	v1 "k8s.io/api/networking/v1"
 	"k8s.io/api/networking/v1beta1"
@@ -30,12 +31,6 @@ import (
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
-var (
-	ingressAddCount    = eventCount.WithLabelValues("ingress", "add")
-	ingressUpdateCount = eventCount.WithLabelValues("ingress", "update")
-	ingressDeleteCount = eventCount.WithLabelValues("ingress", "delete")
-)
-
 // Ingress implements discovery of Kubernetes ingress.
 type Ingress struct {
 	logger   log.Logger
@@ -45,8 +40,18 @@ type Ingress struct {
 }
 
 // NewIngress returns a new ingress discovery.
-func NewIngress(l log.Logger, inf cache.SharedInformer) *Ingress {
-	s := &Ingress{logger: l, informer: inf, store: inf.GetStore(), queue: workqueue.NewNamed("ingress")}
+func NewIngress(l log.Logger, inf cache.SharedInformer, eventCount *prometheus.CounterVec) *Ingress {
+	ingressAddCount := eventCount.WithLabelValues(RoleIngress.String(), MetricLabelRoleAdd)
+	ingressUpdateCount := eventCount.WithLabelValues(RoleIngress.String(), MetricLabelRoleUpdate)
+	ingressDeleteCount := eventCount.WithLabelValues(RoleIngress.String(), MetricLabelRoleDelete)
+
+	s := &Ingress{
+		logger:   l,
+		informer: inf,
+		store:    inf.GetStore(),
+		queue:    workqueue.NewNamed(RoleIngress.String()),
+	}
+
 	_, err := s.informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(o interface{}) {
 			ingressAddCount.Inc()

discovery/kubernetes/kubernetes.go

@@ -58,24 +58,14 @@ import (
 const (
 	// metaLabelPrefix is the meta prefix used for all meta labels.
 	// in this discovery.
-	metaLabelPrefix  = model.MetaLabelPrefix + "kubernetes_"
-	namespaceLabel   = metaLabelPrefix + "namespace"
-	metricsNamespace = "prometheus_sd_kubernetes"
-	presentValue     = model.LabelValue("true")
+	metaLabelPrefix = model.MetaLabelPrefix + "kubernetes_"
+	namespaceLabel  = metaLabelPrefix + "namespace"
+	presentValue    = model.LabelValue("true")
 )
 
 var (
 	// Http header.
 	userAgent = fmt.Sprintf("Prometheus/%s", version.Version)
-	// Custom events metric.
-	eventCount = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Namespace: metricsNamespace,
-			Name:      "events_total",
-			Help:      "The number of Kubernetes events handled.",
-		},
-		[]string{"role", "event"},
-	)
 	// DefaultSDConfig is the default Kubernetes SD configuration.
 	DefaultSDConfig = SDConfig{
 		HTTPClientConfig: config.DefaultHTTPClientConfig,
@@ -84,15 +74,6 @@ var (
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(eventCount)
-	// Initialize metric vectors.
-	for _, role := range []string{"endpointslice", "endpoints", "node", "pod", "service", "ingress"} {
-		for _, evt := range []string{"add", "delete", "update"} {
-			eventCount.WithLabelValues(role, evt)
-		}
-	}
-	(&clientGoRequestMetricAdapter{}).Register(prometheus.DefaultRegisterer)
-	(&clientGoWorkqueueMetricsProvider{}).Register(prometheus.DefaultRegisterer)
 }
 
 // Role is role of the service in Kubernetes.
@@ -121,6 +102,16 @@ func (c *Role) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	}
 }
 
+func (c Role) String() string {
+	return string(c)
+}
+
+const (
+	MetricLabelRoleAdd    = "add"
+	MetricLabelRoleDelete = "delete"
+	MetricLabelRoleUpdate = "update"
+)
+
 // SDConfig is the configuration for Kubernetes service discovery.
 type SDConfig struct {
 	APIServer          config.URL              `yaml:"api_server,omitempty"`
@@ -137,7 +128,7 @@ func (*SDConfig) Name() string { return "kubernetes" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return New(opts.Logger, c)
+	return New(opts.Logger, opts.Registerer, c)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -274,6 +265,8 @@ type Discovery struct {
 	selectors          roleSelector
 	ownNamespace       string
 	attachMetadata     AttachMetadataConfig
+	eventCount         *prometheus.CounterVec
+	metricRegisterer   discovery.MetricRegisterer
 }
 
 func (d *Discovery) getNamespaces() []string {
@@ -292,7 +285,7 @@ func (d *Discovery) getNamespaces() []string {
 }
 
 // New creates a new Kubernetes discovery for the given role.
-func New(l log.Logger, conf *SDConfig) (*Discovery, error) {
+func New(l log.Logger, reg prometheus.Registerer, conf *SDConfig) (*Discovery, error) {
 	if l == nil {
 		l = log.NewNopLogger()
 	}
@@ -346,7 +339,7 @@ func New(l log.Logger, conf *SDConfig) (*Discovery, error) {
 		return nil, err
 	}
 
-	return &Discovery{
+	d := &Discovery{
 		client:             c,
 		logger:             l,
 		role:               conf.Role,
@@ -355,7 +348,37 @@ func New(l log.Logger, conf *SDConfig) (*Discovery, error) {
 		selectors:          mapSelector(conf.Selectors),
 		ownNamespace:       ownNamespace,
 		attachMetadata:     conf.AttachMetadata,
-	}, nil
+		eventCount: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: discovery.KubernetesMetricsNamespace,
+				Name:      "events_total",
+				Help:      "The number of Kubernetes events handled.",
+			},
+			[]string{"role", "event"},
+		),
+	}
+
+	d.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{d.eventCount})
+
+	// Initialize metric vectors.
+	for _, role := range []string{
+		RoleEndpointSlice.String(),
+		RoleEndpoint.String(),
+		RoleNode.String(),
+		RolePod.String(),
+		RoleService.String(),
+		RoleIngress.String(),
+	} {
+		for _, evt := range []string{
+			MetricLabelRoleAdd,
+			MetricLabelRoleDelete,
+			MetricLabelRoleUpdate,
+		} {
+			d.eventCount.WithLabelValues(role, evt)
+		}
+	}
+
+	return d, nil
 }
 
 func mapSelector(rawSelector []SelectorConfig) roleSelector {
@@ -391,6 +414,14 @@ const resyncDisabled = 0
 // Run implements the discoverer interface.
 func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 	d.Lock()
+
+	err := d.metricRegisterer.RegisterMetrics()
+	if err != nil {
+		level.Error(d.logger).Log("msg", "Unable to register metrics", "err", err.Error())
+		return
+	}
+	defer d.metricRegisterer.UnregisterMetrics()
+
 	namespaces := d.getNamespaces()
 
 	switch d.role {
@@ -482,6 +513,7 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 				cache.NewSharedInformer(slw, &apiv1.Service{}, resyncDisabled),
 				cache.NewSharedInformer(plw, &apiv1.Pod{}, resyncDisabled),
 				nodeInf,
+				d.eventCount,
 			)
 			d.discoverers = append(d.discoverers, eps)
 			go eps.endpointSliceInf.Run(ctx.Done())
@@ -541,6 +573,7 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 				cache.NewSharedInformer(slw, &apiv1.Service{}, resyncDisabled),
 				cache.NewSharedInformer(plw, &apiv1.Pod{}, resyncDisabled),
 				nodeInf,
+				d.eventCount,
 			)
 			d.discoverers = append(d.discoverers, eps)
 			go eps.endpointsInf.Run(ctx.Done())
@@ -572,6 +605,7 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 				log.With(d.logger, "role", "pod"),
 				d.newPodsByNodeInformer(plw),
 				nodeInformer,
+				d.eventCount,
 			)
 			d.discoverers = append(d.discoverers, pod)
 			go pod.podInf.Run(ctx.Done())
@@ -594,6 +628,7 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 			svc := NewService(
 				log.With(d.logger, "role", "service"),
 				cache.NewSharedInformer(slw, &apiv1.Service{}, resyncDisabled),
+				d.eventCount,
 			)
 			d.discoverers = append(d.discoverers, svc)
 			go svc.informer.Run(ctx.Done())
@@ -651,13 +686,14 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 			ingress := NewIngress(
 				log.With(d.logger, "role", "ingress"),
 				informer,
+				d.eventCount,
 			)
 			d.discoverers = append(d.discoverers, ingress)
 			go ingress.informer.Run(ctx.Done())
 		}
 	case RoleNode:
 		nodeInformer := d.newNodeInformer(ctx)
-		node := NewNode(log.With(d.logger, "role", "node"), nodeInformer)
+		node := NewNode(log.With(d.logger, "role", "node"), nodeInformer, d.eventCount)
 		d.discoverers = append(d.discoverers, node)
 		go node.informer.Run(ctx.Done())
 	default:

discovery/kubernetes/kubernetes_test.go

@@ -29,6 +29,8 @@ import (
 	"k8s.io/client-go/kubernetes/fake"
 	"k8s.io/client-go/tools/cache"
 
+	"github.com/prometheus/client_golang/prometheus"
+
 	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 	"github.com/prometheus/prometheus/util/testutil"
@@ -49,13 +51,25 @@ func makeDiscoveryWithVersion(role Role, nsDiscovery NamespaceDiscovery, k8sVer
 	fakeDiscovery, _ := clientset.Discovery().(*fakediscovery.FakeDiscovery)
 	fakeDiscovery.FakedServerVersion = &version.Info{GitVersion: k8sVer}
 
-	return &Discovery{
+	d := &Discovery{
 		client:             clientset,
 		logger:             log.NewNopLogger(),
 		role:               role,
 		namespaceDiscovery: &nsDiscovery,
 		ownNamespace:       "own-ns",
-	}, clientset
+		eventCount: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: discovery.KubernetesMetricsNamespace,
+				Name:      "events_total",
+				Help:      "The number of Kubernetes events handled.",
+			},
+			[]string{"role", "event"},
+		),
+	}
+
+	d.metricRegisterer = discovery.NewMetricRegisterer(prometheus.NewRegistry(), []prometheus.Collector{d.eventCount})
+
+	return d, clientset
 }
 
 // makeDiscoveryWithMetadata creates a kubernetes.Discovery instance with the specified metadata config.

discovery/kubernetes/node.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	apiv1 "k8s.io/api/core/v1"
 	"k8s.io/client-go/tools/cache"
@@ -35,12 +36,6 @@ const (
 	NodeLegacyHostIP = "LegacyHostIP"
 )
 
-var (
-	nodeAddCount    = eventCount.WithLabelValues("node", "add")
-	nodeUpdateCount = eventCount.WithLabelValues("node", "update")
-	nodeDeleteCount = eventCount.WithLabelValues("node", "delete")
-)
-
 // Node discovers Kubernetes nodes.
 type Node struct {
 	logger   log.Logger
@@ -50,11 +45,22 @@ type Node struct {
 }
 
 // NewNode returns a new node discovery.
-func NewNode(l log.Logger, inf cache.SharedInformer) *Node {
+func NewNode(l log.Logger, inf cache.SharedInformer, eventCount *prometheus.CounterVec) *Node {
 	if l == nil {
 		l = log.NewNopLogger()
 	}
-	n := &Node{logger: l, informer: inf, store: inf.GetStore(), queue: workqueue.NewNamed("node")}
+
+	nodeAddCount := eventCount.WithLabelValues(RoleNode.String(), MetricLabelRoleAdd)
+	nodeUpdateCount := eventCount.WithLabelValues(RoleNode.String(), MetricLabelRoleUpdate)
+	nodeDeleteCount := eventCount.WithLabelValues(RoleNode.String(), MetricLabelRoleDelete)
+
+	n := &Node{
+		logger:   l,
+		informer: inf,
+		store:    inf.GetStore(),
+		queue:    workqueue.NewNamed(RoleNode.String()),
+	}
+
 	_, err := n.informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(o interface{}) {
 			nodeAddCount.Inc()

discovery/kubernetes/pod.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	apiv1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -34,12 +35,6 @@ import (
 
 const nodeIndex = "node"
 
-var (
-	podAddCount    = eventCount.WithLabelValues("pod", "add")
-	podUpdateCount = eventCount.WithLabelValues("pod", "update")
-	podDeleteCount = eventCount.WithLabelValues("pod", "delete")
-)
-
 // Pod discovers new pod targets.
 type Pod struct {
 	podInf           cache.SharedIndexInformer
@@ -51,18 +46,22 @@ type Pod struct {
 }
 
 // NewPod creates a new pod discovery.
-func NewPod(l log.Logger, pods cache.SharedIndexInformer, nodes cache.SharedInformer) *Pod {
+func NewPod(l log.Logger, pods cache.SharedIndexInformer, nodes cache.SharedInformer, eventCount *prometheus.CounterVec) *Pod {
 	if l == nil {
 		l = log.NewNopLogger()
 	}
 
+	podAddCount := eventCount.WithLabelValues(RolePod.String(), MetricLabelRoleAdd)
+	podDeleteCount := eventCount.WithLabelValues(RolePod.String(), MetricLabelRoleDelete)
+	podUpdateCount := eventCount.WithLabelValues(RolePod.String(), MetricLabelRoleUpdate)
+
 	p := &Pod{
 		podInf:           pods,
 		nodeInf:          nodes,
 		withNodeMetadata: nodes != nil,
 		store:            pods.GetStore(),
 		logger:           l,
-		queue:            workqueue.NewNamed("pod"),
+		queue:            workqueue.NewNamed(RolePod.String()),
 	}
 	_, err := p.podInf.AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(o interface{}) {

discovery/kubernetes/service.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	apiv1 "k8s.io/api/core/v1"
 	"k8s.io/client-go/tools/cache"
@@ -30,12 +31,6 @@ import (
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
-var (
-	svcAddCount    = eventCount.WithLabelValues("service", "add")
-	svcUpdateCount = eventCount.WithLabelValues("service", "update")
-	svcDeleteCount = eventCount.WithLabelValues("service", "delete")
-)
-
 // Service implements discovery of Kubernetes services.
 type Service struct {
 	logger   log.Logger
@@ -45,11 +40,22 @@ type Service struct {
 }
 
 // NewService returns a new service discovery.
-func NewService(l log.Logger, inf cache.SharedInformer) *Service {
+func NewService(l log.Logger, inf cache.SharedInformer, eventCount *prometheus.CounterVec) *Service {
 	if l == nil {
 		l = log.NewNopLogger()
 	}
-	s := &Service{logger: l, informer: inf, store: inf.GetStore(), queue: workqueue.NewNamed("service")}
+
+	svcAddCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleAdd)
+	svcUpdateCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleUpdate)
+	svcDeleteCount := eventCount.WithLabelValues(RoleService.String(), MetricLabelRoleDelete)
+
+	s := &Service{
+		logger:   l,
+		informer: inf,
+		store:    inf.GetStore(),
+		queue:    workqueue.NewNamed(RoleService.String()),
+	}
+
 	_, err := s.informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(o interface{}) {
 			svcAddCount.Inc()

discovery/legacymanager/manager.go

@@ -28,48 +28,6 @@ import (
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
-var (
-	failedConfigs = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Name: "prometheus_sd_failed_configs",
-			Help: "Current number of service discovery configurations that failed to load.",
-		},
-		[]string{"name"},
-	)
-	discoveredTargets = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Name: "prometheus_sd_discovered_targets",
-			Help: "Current number of discovered targets.",
-		},
-		[]string{"name", "config"},
-	)
-	receivedUpdates = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_received_updates_total",
-			Help: "Total number of update events received from the SD providers.",
-		},
-		[]string{"name"},
-	)
-	delayedUpdates = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_updates_delayed_total",
-			Help: "Total number of update events that couldn't be sent immediately.",
-		},
-		[]string{"name"},
-	)
-	sentUpdates = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_updates_total",
-			Help: "Total number of update events sent to the SD consumers.",
-		},
-		[]string{"name"},
-	)
-)
-
-func RegisterMetrics() {
-	prometheus.MustRegister(failedConfigs, discoveredTargets, receivedUpdates, delayedUpdates, sentUpdates)
-}
-
 type poolKey struct {
 	setName  string
 	provider string
@@ -84,7 +42,7 @@ type provider struct {
 }
 
 // NewManager is the Discovery Manager constructor.
-func NewManager(ctx context.Context, logger log.Logger, options ...func(*Manager)) *Manager {
+func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Registerer, options ...func(*Manager)) *Manager {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -96,10 +54,21 @@ func NewManager(ctx context.Context, logger log.Logger, options ...func(*Manager
 		ctx:            ctx,
 		updatert:       5 * time.Second,
 		triggerSend:    make(chan struct{}, 1),
+		registerer:     registerer,
 	}
 	for _, option := range options {
 		option(mgr)
 	}
+
+	// Register the metrics.
+	// We have to do this after setting all options, so that the name of the Manager is set.
+	if metrics, err := discovery.NewMetrics(registerer, mgr.name); err == nil {
+		mgr.metrics = metrics
+	} else {
+		level.Error(logger).Log("msg", "Failed to create discovery manager metrics", "manager", mgr.name, "err", err)
+		return nil
+	}
+
 	return mgr
 }
 
@@ -135,6 +104,11 @@ type Manager struct {
 
 	// The triggerSend channel signals to the manager that new updates have been received from providers.
 	triggerSend chan struct{}
+
+	// A registerer for all service discovery metrics.
+	registerer prometheus.Registerer
+
+	metrics *discovery.Metrics
 }
 
 // Run starts the background processing.
@@ -157,7 +131,7 @@ func (m *Manager) ApplyConfig(cfg map[string]discovery.Configs) error {
 
 	for pk := range m.targets {
 		if _, ok := cfg[pk.setName]; !ok {
-			discoveredTargets.DeleteLabelValues(m.name, pk.setName)
+			m.metrics.DiscoveredTargets.DeleteLabelValues(m.name, pk.setName)
 		}
 	}
 	m.cancelDiscoverers()
@@ -168,9 +142,9 @@ func (m *Manager) ApplyConfig(cfg map[string]discovery.Configs) error {
 	failedCount := 0
 	for name, scfg := range cfg {
 		failedCount += m.registerProviders(scfg, name)
-		discoveredTargets.WithLabelValues(m.name, name).Set(0)
+		m.metrics.DiscoveredTargets.WithLabelValues(name).Set(0)
 	}
-	failedConfigs.WithLabelValues(m.name).Set(float64(failedCount))
+	m.metrics.FailedConfigs.Set(float64(failedCount))
 
 	for _, prov := range m.providers {
 		m.startProvider(m.ctx, prov)
@@ -207,7 +181,7 @@ func (m *Manager) updater(ctx context.Context, p *provider, updates chan []*targ
 		case <-ctx.Done():
 			return
 		case tgs, ok := <-updates:
-			receivedUpdates.WithLabelValues(m.name).Inc()
+			m.metrics.ReceivedUpdates.Inc()
 			if !ok {
 				level.Debug(m.logger).Log("msg", "Discoverer channel closed", "provider", p.name)
 				return
@@ -236,11 +210,11 @@ func (m *Manager) sender() {
 		case <-ticker.C: // Some discoverers send updates too often so we throttle these with the ticker.
 			select {
 			case <-m.triggerSend:
-				sentUpdates.WithLabelValues(m.name).Inc()
+				m.metrics.SentUpdates.Inc()
 				select {
 				case m.syncCh <- m.allGroups():
 				default:
-					delayedUpdates.WithLabelValues(m.name).Inc()
+					m.metrics.DelayedUpdates.Inc()
 					level.Debug(m.logger).Log("msg", "Discovery receiver's channel was full so will retry the next cycle")
 					select {
 					case m.triggerSend <- struct{}{}:
@@ -288,7 +262,7 @@ func (m *Manager) allGroups() map[string][]*targetgroup.Group {
 		}
 	}
 	for setName, v := range n {
-		discoveredTargets.WithLabelValues(m.name, setName).Set(float64(v))
+		m.metrics.DiscoveredTargets.WithLabelValues(setName).Set(float64(v))
 	}
 	return tSets
 }
@@ -309,7 +283,8 @@ func (m *Manager) registerProviders(cfgs discovery.Configs, setName string) int
 		}
 		typ := cfg.Name()
 		d, err := cfg.NewDiscoverer(discovery.DiscovererOptions{
-			Logger: log.With(m.logger, "discovery", typ, "config", setName),
+			Logger:     log.With(m.logger, "discovery", typ, "config", setName),
+			Registerer: m.registerer,
 		})
 		if err != nil {
 			level.Error(m.logger).Log("msg", "Cannot create service discovery", "err", err, "type", typ, "config", setName)

discovery/legacymanager/manager_test.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	client_testutil "github.com/prometheus/client_golang/prometheus/testutil"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
@@ -664,7 +665,8 @@ func TestTargetUpdatesOrder(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			discoveryManager := NewManager(ctx, log.NewNopLogger())
+			discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+			require.NotNil(t, discoveryManager)
 			discoveryManager.updatert = 100 * time.Millisecond
 
 			var totalUpdatesCount int
@@ -746,7 +748,8 @@ func verifyPresence(t *testing.T, tSets map[poolKey]map[string]*targetgroup.Grou
 func TestTargetSetRecreatesTargetGroupsEveryRun(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -774,7 +777,8 @@ func TestTargetSetRecreatesTargetGroupsEveryRun(t *testing.T) {
 func TestDiscovererConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -798,7 +802,8 @@ func TestDiscovererConfigs(t *testing.T) {
 func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -837,7 +842,8 @@ func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 func TestIdenticalConfigurationsAreCoalesced(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, nil)
+	discoveryManager := NewManager(ctx, nil, prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -868,7 +874,8 @@ func TestApplyConfigDoesNotModifyStaticTargets(t *testing.T) {
 	}
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -893,7 +900,8 @@ func (e errorConfig) NewDiscoverer(discovery.DiscovererOptions) (discovery.Disco
 func TestGaugeFailedConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -907,7 +915,7 @@ func TestGaugeFailedConfigs(t *testing.T) {
 	discoveryManager.ApplyConfig(c)
 	<-discoveryManager.SyncCh()
 
-	failedCount := client_testutil.ToFloat64(failedConfigs)
+	failedCount := client_testutil.ToFloat64(discoveryManager.metrics.FailedConfigs)
 	if failedCount != 3 {
 		t.Fatalf("Expected to have 3 failed configs, got: %v", failedCount)
 	}
@@ -918,7 +926,7 @@ func TestGaugeFailedConfigs(t *testing.T) {
 	discoveryManager.ApplyConfig(c)
 	<-discoveryManager.SyncCh()
 
-	failedCount = client_testutil.ToFloat64(failedConfigs)
+	failedCount = client_testutil.ToFloat64(discoveryManager.metrics.FailedConfigs)
 	if failedCount != 0 {
 		t.Fatalf("Expected to get no failed config, got: %v", failedCount)
 	}
@@ -1049,7 +1057,8 @@ func TestCoordinationWithReceiver(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			mgr := NewManager(ctx, nil)
+			mgr := NewManager(ctx, nil, prometheus.NewRegistry())
+			require.NotNil(t, mgr)
 			mgr.updatert = updateDelay
 			go mgr.Run()
 

discovery/linode/linode.go

@@ -67,24 +67,15 @@ const (
 )
 
 // DefaultSDConfig is the default Linode SD configuration.
-var (
-	DefaultSDConfig = SDConfig{
-		TagSeparator:     ",",
-		Port:             80,
-		RefreshInterval:  model.Duration(60 * time.Second),
-		HTTPClientConfig: config.DefaultHTTPClientConfig,
-	}
-
-	failuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_linode_failures_total",
-			Help: "Number of Linode service discovery refresh failures.",
-		})
-)
+var DefaultSDConfig = SDConfig{
+	TagSeparator:     ",",
+	Port:             80,
+	RefreshInterval:  model.Duration(60 * time.Second),
+	HTTPClientConfig: config.DefaultHTTPClientConfig,
+}
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(failuresCount)
 }
 
 // SDConfig is the configuration for Linode based service discovery.
@@ -101,7 +92,7 @@ func (*SDConfig) Name() string { return "linode" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -131,16 +122,22 @@ type Discovery struct {
 	pollCount            int
 	lastResults          []*targetgroup.Group
 	eventPollingEnabled  bool
+	failuresCount        prometheus.Counter
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	d := &Discovery{
 		port:                 conf.Port,
 		tagSeparator:         conf.TagSeparator,
 		pollCount:            0,
 		lastRefreshTimestamp: time.Now().UTC(),
 		eventPollingEnabled:  true,
+		failuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_linode_failures_total",
+				Help: "Number of Linode service discovery refresh failures.",
+			}),
 	}
 
 	rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "linode_sd")
@@ -158,10 +155,14 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	d.client = &client
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"linode",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "linode",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+			Metrics:  []prometheus.Collector{d.failuresCount},
+		},
 	)
 	return d, nil
 }
@@ -222,14 +223,14 @@ func (d *Discovery) refreshData(ctx context.Context) ([]*targetgroup.Group, erro
 	// Gather all linode instances.
 	instances, err := d.client.ListInstances(ctx, &linodego.ListOptions{PageSize: 500})
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, err
 	}
 
 	// Gather detailed IP address info for all IPs on all linode instances.
 	detailedIPs, err := d.client.ListIPAddresses(ctx, &linodego.ListOptions{PageSize: 500})
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, err
 	}
 

discovery/linode/linode_test.go

@@ -20,6 +20,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
@@ -52,7 +53,7 @@ func TestLinodeSDRefresh(t *testing.T) {
 		Credentials: tokenID,
 		Type:        "Bearer",
 	}
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 	endpoint, err := url.Parse(sdmock.Mock.Endpoint())
 	require.NoError(t, err)
@@ -61,12 +62,12 @@ func TestLinodeSDRefresh(t *testing.T) {
 	tgs, err := d.refresh(context.Background())
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 4, len(tg.Targets))
+	require.Len(t, tg.Targets, 4)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/manager.go

@@ -28,48 +28,6 @@ import (
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
-var (
-	failedConfigs = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Name: "prometheus_sd_failed_configs",
-			Help: "Current number of service discovery configurations that failed to load.",
-		},
-		[]string{"name"},
-	)
-	discoveredTargets = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Name: "prometheus_sd_discovered_targets",
-			Help: "Current number of discovered targets.",
-		},
-		[]string{"name", "config"},
-	)
-	receivedUpdates = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_received_updates_total",
-			Help: "Total number of update events received from the SD providers.",
-		},
-		[]string{"name"},
-	)
-	delayedUpdates = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_updates_delayed_total",
-			Help: "Total number of update events that couldn't be sent immediately.",
-		},
-		[]string{"name"},
-	)
-	sentUpdates = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_updates_total",
-			Help: "Total number of update events sent to the SD consumers.",
-		},
-		[]string{"name"},
-	)
-)
-
-func RegisterMetrics() {
-	prometheus.MustRegister(failedConfigs, discoveredTargets, receivedUpdates, delayedUpdates, sentUpdates)
-}
-
 type poolKey struct {
 	setName  string
 	provider string
@@ -107,7 +65,7 @@ func (p *Provider) Config() interface{} {
 }
 
 // NewManager is the Discovery Manager constructor.
-func NewManager(ctx context.Context, logger log.Logger, options ...func(*Manager)) *Manager {
+func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Registerer, options ...func(*Manager)) *Manager {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -118,10 +76,21 @@ func NewManager(ctx context.Context, logger log.Logger, options ...func(*Manager
 		ctx:         ctx,
 		updatert:    5 * time.Second,
 		triggerSend: make(chan struct{}, 1),
+		registerer:  registerer,
 	}
 	for _, option := range options {
 		option(mgr)
 	}
+
+	// Register the metrics.
+	// We have to do this after setting all options, so that the name of the Manager is set.
+	if metrics, err := NewMetrics(registerer, mgr.name); err == nil {
+		mgr.metrics = metrics
+	} else {
+		level.Error(logger).Log("msg", "Failed to create discovery manager metrics", "manager", mgr.name, "err", err)
+		return nil
+	}
+
 	return mgr
 }
 
@@ -170,6 +139,11 @@ type Manager struct {
 
 	// lastProvider counts providers registered during Manager's lifetime.
 	lastProvider uint
+
+	// A registerer for all service discovery metrics.
+	registerer prometheus.Registerer
+
+	metrics *Metrics
 }
 
 // Providers returns the currently configured SD providers.
@@ -200,7 +174,7 @@ func (m *Manager) ApplyConfig(cfg map[string]Configs) error {
 	for name, scfg := range cfg {
 		failedCount += m.registerProviders(scfg, name)
 	}
-	failedConfigs.WithLabelValues(m.name).Set(float64(failedCount))
+	m.metrics.FailedConfigs.Set(float64(failedCount))
 
 	var (
 		wg sync.WaitGroup
@@ -230,13 +204,13 @@ func (m *Manager) ApplyConfig(cfg map[string]Configs) error {
 			// Remove obsolete subs' targets.
 			if _, ok := prov.newSubs[s]; !ok {
 				delete(m.targets, poolKey{s, prov.name})
-				discoveredTargets.DeleteLabelValues(m.name, s)
+				m.metrics.DiscoveredTargets.DeleteLabelValues(m.name, s)
 			}
 		}
 		// Set metrics and targets for new subs.
 		for s := range prov.newSubs {
 			if _, ok := prov.subs[s]; !ok {
-				discoveredTargets.WithLabelValues(m.name, s).Set(0)
+				m.metrics.DiscoveredTargets.WithLabelValues(s).Set(0)
 			}
 			if l := len(refTargets); l > 0 {
 				m.targets[poolKey{s, prov.name}] = make(map[string]*targetgroup.Group, l)
@@ -316,7 +290,7 @@ func (m *Manager) updater(ctx context.Context, p *Provider, updates chan []*targ
 		case <-ctx.Done():
 			return
 		case tgs, ok := <-updates:
-			receivedUpdates.WithLabelValues(m.name).Inc()
+			m.metrics.ReceivedUpdates.Inc()
 			if !ok {
 				level.Debug(m.logger).Log("msg", "Discoverer channel closed", "provider", p.name)
 				// Wait for provider cancellation to ensure targets are cleaned up when expected.
@@ -349,11 +323,11 @@ func (m *Manager) sender() {
 		case <-ticker.C: // Some discoverers send updates too often, so we throttle these with the ticker.
 			select {
 			case <-m.triggerSend:
-				sentUpdates.WithLabelValues(m.name).Inc()
+				m.metrics.SentUpdates.Inc()
 				select {
 				case m.syncCh <- m.allGroups():
 				default:
-					delayedUpdates.WithLabelValues(m.name).Inc()
+					m.metrics.DelayedUpdates.Inc()
 					level.Debug(m.logger).Log("msg", "Discovery receiver's channel was full so will retry the next cycle")
 					select {
 					case m.triggerSend <- struct{}{}:
@@ -405,7 +379,7 @@ func (m *Manager) allGroups() map[string][]*targetgroup.Group {
 		}
 	}
 	for setName, v := range n {
-		discoveredTargets.WithLabelValues(m.name, setName).Set(float64(v))
+		m.metrics.DiscoveredTargets.WithLabelValues(setName).Set(float64(v))
 	}
 	return tSets
 }
@@ -428,6 +402,7 @@ func (m *Manager) registerProviders(cfgs Configs, setName string) int {
 		d, err := cfg.NewDiscoverer(DiscovererOptions{
 			Logger:            log.With(m.logger, "discovery", typ, "config", setName),
 			HTTPClientOptions: m.httpOpts,
+			Registerer:        m.registerer,
 		})
 		if err != nil {
 			level.Error(m.logger).Log("msg", "Cannot create service discovery", "err", err, "type", typ, "config", setName)

discovery/manager_test.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	client_testutil "github.com/prometheus/client_golang/prometheus/testutil"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
@@ -664,7 +665,8 @@ func TestTargetUpdatesOrder(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			discoveryManager := NewManager(ctx, log.NewNopLogger())
+			discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+			require.NotNil(t, discoveryManager)
 			discoveryManager.updatert = 100 * time.Millisecond
 
 			var totalUpdatesCount int
@@ -778,7 +780,8 @@ func pk(provider, setName string, n int) poolKey {
 func TestTargetSetTargetGroupsPresentOnConfigReload(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -790,27 +793,28 @@ func TestTargetSetTargetGroupsPresentOnConfigReload(t *testing.T) {
 	discoveryManager.ApplyConfig(c)
 
 	syncedTargets := <-discoveryManager.SyncCh()
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 	p := pk("static", "prometheus", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(discoveryManager.targets))
+	require.Len(t, discoveryManager.targets, 1)
 
 	discoveryManager.ApplyConfig(c)
 
 	syncedTargets = <-discoveryManager.SyncCh()
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(discoveryManager.targets))
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, discoveryManager.targets, 1)
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 }
 
 func TestTargetSetTargetGroupsPresentOnConfigRename(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -822,12 +826,12 @@ func TestTargetSetTargetGroupsPresentOnConfigRename(t *testing.T) {
 	discoveryManager.ApplyConfig(c)
 
 	syncedTargets := <-discoveryManager.SyncCh()
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 	p := pk("static", "prometheus", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(discoveryManager.targets))
+	require.Len(t, discoveryManager.targets, 1)
 
 	c["prometheus2"] = c["prometheus"]
 	delete(c, "prometheus")
@@ -836,16 +840,17 @@ func TestTargetSetTargetGroupsPresentOnConfigRename(t *testing.T) {
 	syncedTargets = <-discoveryManager.SyncCh()
 	p = pk("static", "prometheus2", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(discoveryManager.targets))
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, discoveryManager.targets, 1)
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus2", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus2"]))
+	require.Len(t, syncedTargets["prometheus2"], 1)
 }
 
 func TestTargetSetTargetGroupsPresentOnConfigDuplicateAndDeleteOriginal(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -860,30 +865,31 @@ func TestTargetSetTargetGroupsPresentOnConfigDuplicateAndDeleteOriginal(t *testi
 	c["prometheus2"] = c["prometheus"]
 	discoveryManager.ApplyConfig(c)
 	syncedTargets := <-discoveryManager.SyncCh()
-	require.Equal(t, 2, len(syncedTargets))
+	require.Len(t, syncedTargets, 2)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus2", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus2"]))
+	require.Len(t, syncedTargets["prometheus2"], 1)
 	p := pk("static", "prometheus", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 2, len(discoveryManager.targets))
+	require.Len(t, discoveryManager.targets, 2)
 
 	delete(c, "prometheus")
 	discoveryManager.ApplyConfig(c)
 	syncedTargets = <-discoveryManager.SyncCh()
 	p = pk("static", "prometheus2", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(discoveryManager.targets))
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, discoveryManager.targets, 1)
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus2", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus2"]))
+	require.Len(t, syncedTargets["prometheus2"], 1)
 }
 
 func TestTargetSetTargetGroupsPresentOnConfigChange(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -895,9 +901,9 @@ func TestTargetSetTargetGroupsPresentOnConfigChange(t *testing.T) {
 	discoveryManager.ApplyConfig(c)
 
 	syncedTargets := <-discoveryManager.SyncCh()
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 
 	var mu sync.Mutex
 	c["prometheus2"] = Configs{
@@ -912,39 +918,40 @@ func TestTargetSetTargetGroupsPresentOnConfigChange(t *testing.T) {
 	// Original targets should be present as soon as possible.
 	syncedTargets = <-discoveryManager.SyncCh()
 	mu.Unlock()
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 
 	// prometheus2 configs should be ready on second sync.
 	syncedTargets = <-discoveryManager.SyncCh()
-	require.Equal(t, 2, len(syncedTargets))
+	require.Len(t, syncedTargets, 2)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus2", "{__address__=\"bar:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus2"]))
+	require.Len(t, syncedTargets["prometheus2"], 1)
 
 	p := pk("static", "prometheus", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
 	p = pk("lockstatic", "prometheus2", 1)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"bar:9090\"}", true)
-	require.Equal(t, 2, len(discoveryManager.targets))
+	require.Len(t, discoveryManager.targets, 2)
 
 	// Delete part of config and ensure only original targets exist.
 	delete(c, "prometheus2")
 	discoveryManager.ApplyConfig(c)
 	syncedTargets = <-discoveryManager.SyncCh()
-	require.Equal(t, 1, len(discoveryManager.targets))
+	require.Len(t, discoveryManager.targets, 1)
 	verifyPresence(t, discoveryManager.targets, pk("static", "prometheus", 0), "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 }
 
 func TestTargetSetRecreatesTargetGroupsOnConfigChange(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -959,31 +966,32 @@ func TestTargetSetRecreatesTargetGroupsOnConfigChange(t *testing.T) {
 	p := pk("static", "prometheus", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"bar:9090\"}", true)
-	require.Equal(t, 1, len(discoveryManager.targets))
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, discoveryManager.targets, 1)
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"bar:9090\"}", true)
-	require.Equal(t, 2, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 2)
 
 	c["prometheus"] = Configs{
 		staticConfig("foo:9090"),
 	}
 	discoveryManager.ApplyConfig(c)
 	syncedTargets = <-discoveryManager.SyncCh()
-	require.Equal(t, 1, len(discoveryManager.targets))
+	require.Len(t, discoveryManager.targets, 1)
 	p = pk("static", "prometheus", 1)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"bar:9090\"}", false)
-	require.Equal(t, 1, len(discoveryManager.targets))
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, discoveryManager.targets, 1)
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 }
 
 func TestDiscovererConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -1001,12 +1009,12 @@ func TestDiscovererConfigs(t *testing.T) {
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"bar:9090\"}", true)
 	p = pk("static", "prometheus", 1)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"baz:9090\"}", true)
-	require.Equal(t, 2, len(discoveryManager.targets))
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, discoveryManager.targets, 2)
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"bar:9090\"}", true)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"baz:9090\"}", true)
-	require.Equal(t, 3, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 3)
 }
 
 // TestTargetSetRecreatesEmptyStaticConfigs ensures that reloading a config file after
@@ -1015,7 +1023,8 @@ func TestDiscovererConfigs(t *testing.T) {
 func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -1029,9 +1038,9 @@ func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 	syncedTargets := <-discoveryManager.SyncCh()
 	p := pk("static", "prometheus", 0)
 	verifyPresence(t, discoveryManager.targets, p, "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets))
+	require.Len(t, syncedTargets, 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 
 	c["prometheus"] = Configs{
 		StaticConfig{{}},
@@ -1052,8 +1061,8 @@ func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 	if len(group.Targets) != 0 {
 		t.Fatalf("Invalid number of targets: expected 0, got %d", len(group.Targets))
 	}
-	require.Equal(t, 1, len(syncedTargets))
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets, 1)
+	require.Len(t, syncedTargets["prometheus"], 1)
 	if lbls := syncedTargets["prometheus"][0].Labels; lbls != nil {
 		t.Fatalf("Unexpected Group: expected nil Labels, got %v", lbls)
 	}
@@ -1062,7 +1071,8 @@ func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 func TestIdenticalConfigurationsAreCoalesced(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, nil)
+	discoveryManager := NewManager(ctx, nil, prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -1082,11 +1092,11 @@ func TestIdenticalConfigurationsAreCoalesced(t *testing.T) {
 	if len(discoveryManager.providers) != 1 {
 		t.Fatalf("Invalid number of providers: expected 1, got %d", len(discoveryManager.providers))
 	}
-	require.Equal(t, 2, len(syncedTargets))
+	require.Len(t, syncedTargets, 2)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus"]))
+	require.Len(t, syncedTargets["prometheus"], 1)
 	verifySyncedPresence(t, syncedTargets, "prometheus2", "{__address__=\"foo:9090\"}", true)
-	require.Equal(t, 1, len(syncedTargets["prometheus2"]))
+	require.Len(t, syncedTargets["prometheus2"], 1)
 }
 
 func TestApplyConfigDoesNotModifyStaticTargets(t *testing.T) {
@@ -1098,7 +1108,8 @@ func TestApplyConfigDoesNotModifyStaticTargets(t *testing.T) {
 	}
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -1144,7 +1155,8 @@ func (s lockStaticDiscoverer) Run(ctx context.Context, up chan<- []*targetgroup.
 func TestGaugeFailedConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 
@@ -1158,7 +1170,7 @@ func TestGaugeFailedConfigs(t *testing.T) {
 	discoveryManager.ApplyConfig(c)
 	<-discoveryManager.SyncCh()
 
-	failedCount := client_testutil.ToFloat64(failedConfigs)
+	failedCount := client_testutil.ToFloat64(discoveryManager.metrics.FailedConfigs)
 	if failedCount != 3 {
 		t.Fatalf("Expected to have 3 failed configs, got: %v", failedCount)
 	}
@@ -1169,7 +1181,7 @@ func TestGaugeFailedConfigs(t *testing.T) {
 	discoveryManager.ApplyConfig(c)
 	<-discoveryManager.SyncCh()
 
-	failedCount = client_testutil.ToFloat64(failedConfigs)
+	failedCount = client_testutil.ToFloat64(discoveryManager.metrics.FailedConfigs)
 	if failedCount != 0 {
 		t.Fatalf("Expected to get no failed config, got: %v", failedCount)
 	}
@@ -1300,7 +1312,8 @@ func TestCoordinationWithReceiver(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			mgr := NewManager(ctx, nil)
+			mgr := NewManager(ctx, nil, prometheus.NewRegistry())
+			require.NotNil(t, mgr)
 			mgr.updatert = updateDelay
 			go mgr.Run()
 
@@ -1392,10 +1405,11 @@ func (o onceProvider) Run(_ context.Context, ch chan<- []*targetgroup.Group) {
 
 // TestTargetSetTargetGroupsUpdateDuringApplyConfig is used to detect races when
 // ApplyConfig happens at the same time as targets update.
-func TestTargetSetTargetGroupsUpdateDuringApplyConfig(*testing.T) {
+func TestTargetSetTargetGroupsUpdateDuringApplyConfig(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger())
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
 

discovery/marathon/marathon.go

@@ -28,6 +28,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -83,7 +84,7 @@ func (*SDConfig) Name() string { return "marathon" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(*c, opts.Logger)
+	return NewDiscovery(*c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -132,7 +133,7 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Marathon Discovery.
-func NewDiscovery(conf SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "marathon_sd")
 	if err != nil {
 		return nil, err
@@ -154,10 +155,13 @@ func NewDiscovery(conf SDConfig, logger log.Logger) (*Discovery, error) {
 		appsClient: fetchApps,
 	}
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"marathon",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "marathon",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/marathon/marathon_test.go

@@ -21,6 +21,7 @@ import (
 	"net/http/httptest"
 	"testing"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 
 	"github.com/prometheus/prometheus/discovery/targetgroup"
@@ -36,7 +37,7 @@ func testConfig() SDConfig {
 }
 
 func testUpdateServices(client appListClient) ([]*targetgroup.Group, error) {
-	md, err := NewDiscovery(testConfig(), nil)
+	md, err := NewDiscovery(testConfig(), nil, prometheus.NewRegistry())
 	if err != nil {
 		return nil, err
 	}
@@ -129,7 +130,7 @@ func TestMarathonSDSendGroup(t *testing.T) {
 }
 
 func TestMarathonSDRemoveApp(t *testing.T) {
-	md, err := NewDiscovery(testConfig(), nil)
+	md, err := NewDiscovery(testConfig(), nil, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("%s", err)
 	}

discovery/metrics.go

@@ -0,0 +1,101 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package discovery
+
+import (
+	"fmt"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	clientGoRequestMetrics  = &clientGoRequestMetricAdapter{}
+	clientGoWorkloadMetrics = &clientGoWorkqueueMetricsProvider{}
+)
+
+func init() {
+	clientGoRequestMetrics.RegisterWithK8sGoClient()
+	clientGoWorkloadMetrics.RegisterWithK8sGoClient()
+}
+
+// Metrics to be used with a discovery manager.
+type Metrics struct {
+	FailedConfigs     prometheus.Gauge
+	DiscoveredTargets *prometheus.GaugeVec
+	ReceivedUpdates   prometheus.Counter
+	DelayedUpdates    prometheus.Counter
+	SentUpdates       prometheus.Counter
+}
+
+func NewMetrics(registerer prometheus.Registerer, sdManagerName string) (*Metrics, error) {
+	m := &Metrics{}
+
+	m.FailedConfigs = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Name:        "prometheus_sd_failed_configs",
+			Help:        "Current number of service discovery configurations that failed to load.",
+			ConstLabels: prometheus.Labels{"name": sdManagerName},
+		},
+	)
+
+	m.DiscoveredTargets = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name:        "prometheus_sd_discovered_targets",
+			Help:        "Current number of discovered targets.",
+			ConstLabels: prometheus.Labels{"name": sdManagerName},
+		},
+		[]string{"config"},
+	)
+
+	m.ReceivedUpdates = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name:        "prometheus_sd_received_updates_total",
+			Help:        "Total number of update events received from the SD providers.",
+			ConstLabels: prometheus.Labels{"name": sdManagerName},
+		},
+	)
+
+	m.DelayedUpdates = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name:        "prometheus_sd_updates_delayed_total",
+			Help:        "Total number of update events that couldn't be sent immediately.",
+			ConstLabels: prometheus.Labels{"name": sdManagerName},
+		},
+	)
+
+	m.SentUpdates = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name:        "prometheus_sd_updates_total",
+			Help:        "Total number of update events sent to the SD consumers.",
+			ConstLabels: prometheus.Labels{"name": sdManagerName},
+		},
+	)
+
+	metrics := []prometheus.Collector{
+		m.FailedConfigs,
+		m.DiscoveredTargets,
+		m.ReceivedUpdates,
+		m.DelayedUpdates,
+		m.SentUpdates,
+	}
+
+	for _, collector := range metrics {
+		err := registerer.Register(collector)
+		if err != nil {
+			return nil, fmt.Errorf("failed to register discovery manager metrics: %w", err)
+		}
+	}
+
+	return m, nil
+}

discovery/metrics_k8s_client.go

@@ -11,10 +11,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package kubernetes
+package discovery
 
 import (
 	"context"
+	"fmt"
 	"net/url"
 	"time"
 
@@ -23,13 +24,22 @@ import (
 	"k8s.io/client-go/util/workqueue"
 )
 
-const workqueueMetricsNamespace = metricsNamespace + "_workqueue"
+// This file registers metrics used by the Kubernetes Go client (k8s.io/client-go).
+// Unfortunately, k8s.io/client-go metrics are global.
+// If we instantiate multiple k8s SD instances, their k8s/client-go metrics will overlap.
+// To prevent us from displaying misleading metrics, we register k8s.io/client-go metrics
+// outside of the Kubernetes SD.
+
+const (
+	KubernetesMetricsNamespace = "prometheus_sd_kubernetes"
+	workqueueMetricsNamespace  = KubernetesMetricsNamespace + "_workqueue"
+)
 
 var (
 	// Metrics for client-go's HTTP requests.
 	clientGoRequestResultMetricVec = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
-			Namespace: metricsNamespace,
+			Namespace: KubernetesMetricsNamespace,
 			Name:      "http_request_total",
 			Help:      "Total number of HTTP requests to the Kubernetes API by status code.",
 		},
@@ -37,7 +47,7 @@ var (
 	)
 	clientGoRequestLatencyMetricVec = prometheus.NewSummaryVec(
 		prometheus.SummaryOpts{
-			Namespace:  metricsNamespace,
+			Namespace:  KubernetesMetricsNamespace,
 			Name:       "http_request_duration_seconds",
 			Help:       "Summary of latencies for HTTP requests to the Kubernetes API by endpoint.",
 			Objectives: map[float64]float64{},
@@ -109,17 +119,38 @@ func (noopMetric) Set(float64)     {}
 // Definition of client-go metrics adapters for HTTP requests observation.
 type clientGoRequestMetricAdapter struct{}
 
-func (f *clientGoRequestMetricAdapter) Register(registerer prometheus.Registerer) {
+// Returns all of the Prometheus metrics derived from k8s.io/client-go.
+// This may be used tu register and unregister the metrics.
+func clientGoMetrics() []prometheus.Collector {
+	return []prometheus.Collector{
+		clientGoRequestResultMetricVec,
+		clientGoRequestLatencyMetricVec,
+		clientGoWorkqueueDepthMetricVec,
+		clientGoWorkqueueAddsMetricVec,
+		clientGoWorkqueueLatencyMetricVec,
+		clientGoWorkqueueUnfinishedWorkSecondsMetricVec,
+		clientGoWorkqueueLongestRunningProcessorMetricVec,
+		clientGoWorkqueueWorkDurationMetricVec,
+	}
+}
+
+func RegisterK8sClientMetricsWithPrometheus(registerer prometheus.Registerer) error {
+	for _, collector := range clientGoMetrics() {
+		err := registerer.Register(collector)
+		if err != nil {
+			return fmt.Errorf("failed to register Kubernetes Go Client metrics: %w", err)
+		}
+	}
+	return nil
+}
+
+func (f *clientGoRequestMetricAdapter) RegisterWithK8sGoClient() {
 	metrics.Register(
 		metrics.RegisterOpts{
 			RequestLatency: f,
 			RequestResult:  f,
 		},
 	)
-	registerer.MustRegister(
-		clientGoRequestResultMetricVec,
-		clientGoRequestLatencyMetricVec,
-	)
 }
 
 func (clientGoRequestMetricAdapter) Increment(_ context.Context, code, _, _ string) {
@@ -133,16 +164,8 @@ func (clientGoRequestMetricAdapter) Observe(_ context.Context, _ string, u url.U
 // Definition of client-go workqueue metrics provider definition.
 type clientGoWorkqueueMetricsProvider struct{}
 
-func (f *clientGoWorkqueueMetricsProvider) Register(registerer prometheus.Registerer) {
+func (f *clientGoWorkqueueMetricsProvider) RegisterWithK8sGoClient() {
 	workqueue.SetProvider(f)
-	registerer.MustRegister(
-		clientGoWorkqueueDepthMetricVec,
-		clientGoWorkqueueAddsMetricVec,
-		clientGoWorkqueueLatencyMetricVec,
-		clientGoWorkqueueWorkDurationMetricVec,
-		clientGoWorkqueueUnfinishedWorkSecondsMetricVec,
-		clientGoWorkqueueLongestRunningProcessorMetricVec,
-	)
 }
 
 func (f *clientGoWorkqueueMetricsProvider) NewDepthMetric(name string) workqueue.GaugeMetric {

discovery/moby/docker.go

@@ -26,6 +26,7 @@ import (
 	"github.com/docker/docker/api/types/filters"
 	"github.com/docker/docker/client"
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -80,7 +81,7 @@ func (*DockerSDConfig) Name() string { return "docker" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *DockerSDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDockerDiscovery(c, opts.Logger)
+	return NewDockerDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -114,7 +115,7 @@ type DockerDiscovery struct {
 }
 
 // NewDockerDiscovery returns a new DockerDiscovery which periodically refreshes its targets.
-func NewDockerDiscovery(conf *DockerSDConfig, logger log.Logger) (*DockerDiscovery, error) {
+func NewDockerDiscovery(conf *DockerSDConfig, logger log.Logger, reg prometheus.Registerer) (*DockerDiscovery, error) {
 	var err error
 
 	d := &DockerDiscovery{
@@ -165,10 +166,13 @@ func NewDockerDiscovery(conf *DockerSDConfig, logger log.Logger) (*DockerDiscove
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"docker",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "docker",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/moby/docker_test.go

@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
@@ -37,19 +38,19 @@ host: %s
 	var cfg DockerSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDockerDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDockerDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 3, len(tg.Targets))
+	require.Len(t, tg.Targets, 3)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/moby/dockerswarm.go

@@ -23,6 +23,7 @@ import (
 	"github.com/docker/docker/api/types/filters"
 	"github.com/docker/docker/client"
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/version"
@@ -74,7 +75,7 @@ func (*DockerSwarmSDConfig) Name() string { return "dockerswarm" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *DockerSwarmSDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -117,7 +118,7 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *DockerSwarmSDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *DockerSwarmSDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	var err error
 
 	d := &Discovery{
@@ -168,10 +169,13 @@ func NewDiscovery(conf *DockerSwarmSDConfig, logger log.Logger) (*Discovery, err
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"dockerswarm",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "dockerswarm",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/moby/nodes_test.go

@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
@@ -38,19 +39,19 @@ host: %s
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 5, len(tg.Targets))
+	require.Len(t, tg.Targets, 5)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/moby/services_test.go

@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
@@ -38,19 +39,19 @@ host: %s
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 15, len(tg.Targets))
+	require.Len(t, tg.Targets, 15)
 
 	for i, lbls := range []model.LabelSet{
 		{
@@ -332,19 +333,19 @@ filters:
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg, "tg should not be nil")
 	require.NotNil(t, tg.Targets, "tg.targets should not be nil")
-	require.Equal(t, 4, len(tg.Targets))
+	require.Len(t, tg.Targets, 4)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/moby/tasks_test.go

@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
@@ -38,19 +39,19 @@ host: %s
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 27, len(tg.Targets))
+	require.Len(t, tg.Targets, 27)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/nomad/nomad.go

@@ -49,27 +49,18 @@ const (
 )
 
 // DefaultSDConfig is the default nomad SD configuration.
-var (
-	DefaultSDConfig = SDConfig{
-		AllowStale:       true,
-		HTTPClientConfig: config.DefaultHTTPClientConfig,
-		Namespace:        "default",
-		RefreshInterval:  model.Duration(60 * time.Second),
-		Region:           "global",
-		Server:           "http://localhost:4646",
-		TagSeparator:     ",",
-	}
-
-	failuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_nomad_failures_total",
-			Help: "Number of nomad service discovery refresh failures.",
-		})
-)
+var DefaultSDConfig = SDConfig{
+	AllowStale:       true,
+	HTTPClientConfig: config.DefaultHTTPClientConfig,
+	Namespace:        "default",
+	RefreshInterval:  model.Duration(60 * time.Second),
+	Region:           "global",
+	Server:           "http://localhost:4646",
+	TagSeparator:     ",",
+}
 
 func init() {
 	discovery.RegisterConfig(&SDConfig{})
-	prometheus.MustRegister(failuresCount)
 }
 
 // SDConfig is the configuration for nomad based service discovery.
@@ -88,7 +79,7 @@ func (*SDConfig) Name() string { return "nomad" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -121,10 +112,11 @@ type Discovery struct {
 	region          string
 	server          string
 	tagSeparator    string
+	failuresCount   prometheus.Counter
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	d := &Discovery{
 		allowStale:      conf.AllowStale,
 		namespace:       conf.Namespace,
@@ -132,6 +124,11 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 		region:          conf.Region,
 		server:          conf.Server,
 		tagSeparator:    conf.TagSeparator,
+		failuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_nomad_failures_total",
+				Help: "Number of nomad service discovery refresh failures.",
+			}),
 	}
 
 	HTTPClient, err := config.NewClientFromConfig(conf.HTTPClientConfig, "nomad_sd")
@@ -153,10 +150,14 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	d.client = client
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"nomad",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "nomad",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+			Metrics:  []prometheus.Collector{d.failuresCount},
+		},
 	)
 	return d, nil
 }
@@ -167,7 +168,7 @@ func (d *Discovery) refresh(context.Context) ([]*targetgroup.Group, error) {
 	}
 	stubs, _, err := d.client.Services().List(opts)
 	if err != nil {
-		failuresCount.Inc()
+		d.failuresCount.Inc()
 		return nil, err
 	}
 
@@ -179,7 +180,7 @@ func (d *Discovery) refresh(context.Context) ([]*targetgroup.Group, error) {
 		for _, service := range stub.Services {
 			instances, _, err := d.client.Services().Get(service.ServiceName, opts)
 			if err != nil {
-				failuresCount.Inc()
+				d.failuresCount.Inc()
 				return nil, fmt.Errorf("failed to fetch services: %w", err)
 			}
 

discovery/nomad/nomad_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 )
@@ -127,7 +128,7 @@ func TestConfiguredService(t *testing.T) {
 	conf := &SDConfig{
 		Server: "http://localhost:4646",
 	}
-	_, err := NewDiscovery(conf, nil)
+	_, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
 	require.NoError(t, err)
 }
 
@@ -141,18 +142,18 @@ func TestNomadSDRefresh(t *testing.T) {
 
 	cfg := DefaultSDConfig
 	cfg.Server = endpoint.String()
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	tgs, err := d.refresh(context.Background())
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 1, len(tg.Targets))
+	require.Len(t, tg.Targets, 1)
 
 	lbls := model.LabelSet{
 		"__address__":                  model.LabelValue("127.0.0.1:30456"),

discovery/openstack/hypervisor_test.go

@@ -53,12 +53,12 @@ func TestOpenstackSDHypervisorRefresh(t *testing.T) {
 	hypervisor, _ := mock.openstackAuthSuccess()
 	ctx := context.Background()
 	tgs, err := hypervisor.refresh(ctx)
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 	tg := tgs[0]
 	require.NoError(t, err)
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 2, len(tg.Targets))
+	require.Len(t, tg.Targets, 2)
 
 	for l, v := range map[string]string{
 		"__address__":                          "172.16.70.14:0",

discovery/openstack/instance.go

@@ -145,16 +145,16 @@ func (i *InstanceDiscovery) refresh(ctx context.Context) ([]*targetgroup.Group,
 				openstackLabelUserID:         model.LabelValue(s.UserID),
 			}
 
-			flavorId, ok := s.Flavor["id"].(string)
+			flavorID, ok := s.Flavor["id"].(string)
 			if !ok {
 				level.Warn(i.logger).Log("msg", "Invalid type for flavor id, expected string")
 				continue
 			}
-			labels[openstackLabelInstanceFlavor] = model.LabelValue(flavorId)
+			labels[openstackLabelInstanceFlavor] = model.LabelValue(flavorID)
 
-			imageId, ok := s.Image["id"].(string)
+			imageID, ok := s.Image["id"].(string)
 			if ok {
-				labels[openstackLabelInstanceImage] = model.LabelValue(imageId)
+				labels[openstackLabelInstanceImage] = model.LabelValue(imageID)
 			}
 
 			for k, v := range s.Metadata {

discovery/openstack/instance_test.go

@@ -61,12 +61,12 @@ func TestOpenstackSDInstanceRefresh(t *testing.T) {
 	tgs, err := instance.refresh(ctx)
 
 	require.NoError(t, err)
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 4, len(tg.Targets))
+	require.Len(t, tg.Targets, 4)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/openstack/openstack.go

@@ -24,6 +24,7 @@ import (
 	"github.com/gophercloud/gophercloud"
 	"github.com/gophercloud/gophercloud/openstack"
 	"github.com/mwitkow/go-conntrack"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -70,7 +71,7 @@ func (*SDConfig) Name() string { return "openstack" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -134,16 +135,19 @@ type refresher interface {
 }
 
 // NewDiscovery returns a new OpenStack Discoverer which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, l log.Logger) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, l log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
 	r, err := newRefresher(conf, l)
 	if err != nil {
 		return nil, err
 	}
 	return refresh.NewDiscovery(
-		l,
-		"openstack",
-		time.Duration(conf.RefreshInterval),
-		r.refresh,
+		refresh.Options{
+			Logger:   l,
+			Mech:     "openstack",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: r.refresh,
+			Registry: reg,
+		},
 	), nil
 }
 

discovery/ovhcloud/dedicated_server_test.go

@@ -47,11 +47,11 @@ consumer_key: %s`, mock.URL, ovhcloudApplicationKeyTest, ovhcloudApplicationSecr
 	targetGroups, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(targetGroups))
+	require.Len(t, targetGroups, 1)
 	targetGroup := targetGroups[0]
 	require.NotNil(t, targetGroup)
 	require.NotNil(t, targetGroup.Targets)
-	require.Equal(t, 1, len(targetGroup.Targets))
+	require.Len(t, targetGroup.Targets, 1)
 
 	for i, lbls := range []model.LabelSet{
 		{

discovery/ovhcloud/ovhcloud.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/ovh/go-ovh/ovh"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -93,7 +94,7 @@ func createClient(config *SDConfig) (*ovh.Client, error) {
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(options discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, options.Logger)
+	return NewDiscovery(c, options.Logger, options.Registerer)
 }
 
 func init() {
@@ -140,16 +141,19 @@ func newRefresher(conf *SDConfig, logger log.Logger) (refresher, error) {
 }
 
 // NewDiscovery returns a new OVHcloud Discoverer which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
 	r, err := newRefresher(conf, logger)
 	if err != nil {
 		return nil, err
 	}
 
 	return refresh.NewDiscovery(
-		logger,
-		"ovhcloud",
-		time.Duration(conf.RefreshInterval),
-		r.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "ovhcloud",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: r.refresh,
+			Registry: reg,
+		},
 	), nil
 }

discovery/ovhcloud/ovhcloud_test.go

@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
@@ -122,7 +123,8 @@ func TestDiscoverer(t *testing.T) {
 	conf, _ := getMockConf("vps")
 	logger := testutil.NewLogger(t)
 	_, err := conf.NewDiscoverer(discovery.DiscovererOptions{
-		Logger: logger,
+		Logger:     logger,
+		Registerer: prometheus.NewRegistry(),
 	})
 
 	require.NoError(t, err)

discovery/ovhcloud/vps_test.go

@@ -49,11 +49,11 @@ consumer_key: %s`, mock.URL, ovhcloudApplicationKeyTest, ovhcloudApplicationSecr
 	targetGroups, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(targetGroups))
+	require.Len(t, targetGroups, 1)
 	targetGroup := targetGroups[0]
 	require.NotNil(t, targetGroup)
 	require.NotNil(t, targetGroup.Targets)
-	require.Equal(t, 1, len(targetGroup.Targets))
+	require.Len(t, targetGroup.Targets, 1)
 	for i, lbls := range []model.LabelSet{
 		{
 			"__address__":                               "192.0.2.1",

discovery/puppetdb/puppetdb.go

@@ -29,6 +29,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/grafana/regexp"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/version"
@@ -83,7 +84,7 @@ func (*SDConfig) Name() string { return "puppetdb" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -130,7 +131,7 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new PuppetDB discovery for the given config.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -156,10 +157,13 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"http",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "http",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/puppetdb/puppetdb_test.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
@@ -62,7 +63,7 @@ func TestPuppetSlashInURL(t *testing.T) {
 			Port:             80,
 			RefreshInterval:  model.Duration(30 * time.Second),
 		}
-		d, err := NewDiscovery(&cfg, log.NewNopLogger())
+		d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 		require.NoError(t, err)
 		require.Equal(t, apiURL, d.url)
 	}
@@ -79,7 +80,7 @@ func TestPuppetDBRefresh(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -105,7 +106,7 @@ func TestPuppetDBRefresh(t *testing.T) {
 			Source: ts.URL + "/pdb/query/v4?query=vhosts",
 		},
 	}
-	require.Equal(t, tgs, expectedTargets)
+	require.Equal(t, expectedTargets, tgs)
 }
 
 func TestPuppetDBRefreshWithParameters(t *testing.T) {
@@ -120,7 +121,7 @@ func TestPuppetDBRefreshWithParameters(t *testing.T) {
 		RefreshInterval:   model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -156,7 +157,7 @@ func TestPuppetDBRefreshWithParameters(t *testing.T) {
 			Source: ts.URL + "/pdb/query/v4?query=vhosts",
 		},
 	}
-	require.Equal(t, tgs, expectedTargets)
+	require.Equal(t, expectedTargets, tgs)
 }
 
 func TestPuppetDBInvalidCode(t *testing.T) {
@@ -172,7 +173,7 @@ func TestPuppetDBInvalidCode(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -193,7 +194,7 @@ func TestPuppetDBInvalidFormat(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 
 	ctx := context.Background()

discovery/refresh/refresh.go

@@ -22,29 +22,17 @@ import (
 	"github.com/go-kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
-var (
-	failuresCount = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "prometheus_sd_refresh_failures_total",
-			Help: "Number of refresh failures for the given SD mechanism.",
-		},
-		[]string{"mechanism"},
-	)
-	duration = prometheus.NewSummaryVec(
-		prometheus.SummaryOpts{
-			Name:       "prometheus_sd_refresh_duration_seconds",
-			Help:       "The duration of a refresh in seconds for the given SD mechanism.",
-			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
-		},
-		[]string{"mechanism"},
-	)
-)
-
-func init() {
-	prometheus.MustRegister(duration, failuresCount)
+type Options struct {
+	Logger   log.Logger
+	Mech     string
+	Interval time.Duration
+	RefreshF func(ctx context.Context) ([]*targetgroup.Group, error)
+	Registry prometheus.Registerer
+	Metrics  []prometheus.Collector
 }
 
 // Discovery implements the Discoverer interface.
@@ -54,25 +42,62 @@ type Discovery struct {
 	refreshf func(ctx context.Context) ([]*targetgroup.Group, error)
 
 	failures prometheus.Counter
-	duration prometheus.Observer
+	duration prometheus.Summary
+
+	metricRegisterer discovery.MetricRegisterer
 }
 
 // NewDiscovery returns a Discoverer function that calls a refresh() function at every interval.
-func NewDiscovery(l log.Logger, mech string, interval time.Duration, refreshf func(ctx context.Context) ([]*targetgroup.Group, error)) *Discovery {
-	if l == nil {
-		l = log.NewNopLogger()
+func NewDiscovery(opts Options) *Discovery {
+	var logger log.Logger
+	if opts.Logger == nil {
+		logger = log.NewNopLogger()
+	} else {
+		logger = opts.Logger
 	}
-	return &Discovery{
-		logger:   l,
-		interval: interval,
-		refreshf: refreshf,
-		failures: failuresCount.WithLabelValues(mech),
-		duration: duration.WithLabelValues(mech),
+
+	d := Discovery{
+		logger:   logger,
+		interval: opts.Interval,
+		refreshf: opts.RefreshF,
+		failures: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_refresh_failures_total",
+				Help: "Number of refresh failures for the given SD mechanism.",
+				ConstLabels: prometheus.Labels{
+					"mechanism": opts.Mech,
+				},
+			}),
+		duration: prometheus.NewSummary(
+			prometheus.SummaryOpts{
+				Name:       "prometheus_sd_refresh_duration_seconds",
+				Help:       "The duration of a refresh in seconds for the given SD mechanism.",
+				Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+				ConstLabels: prometheus.Labels{
+					"mechanism": opts.Mech,
+				},
+			}),
 	}
+
+	metrics := []prometheus.Collector{d.failures, d.duration}
+	if opts.Metrics != nil {
+		metrics = append(metrics, opts.Metrics...)
+	}
+
+	d.metricRegisterer = discovery.NewMetricRegisterer(opts.Registry, metrics)
+
+	return &d
 }
 
 // Run implements the Discoverer interface.
 func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
+	err := d.metricRegisterer.RegisterMetrics()
+	if err != nil {
+		level.Error(d.logger).Log("msg", "Unable to register metrics", "err", err.Error())
+		return
+	}
+	defer d.metricRegisterer.UnregisterMetrics()
+
 	// Get an initial set right away.
 	tgs, err := d.refresh(ctx)
 	if err != nil {

discovery/refresh/refresh_test.go

@@ -19,6 +19,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
@@ -65,7 +66,15 @@ func TestRefresh(t *testing.T) {
 		return nil, fmt.Errorf("some error")
 	}
 	interval := time.Millisecond
-	d := NewDiscovery(nil, "test", interval, refresh)
+	d := NewDiscovery(
+		Options{
+			Logger:   nil,
+			Mech:     "test",
+			Interval: interval,
+			RefreshF: refresh,
+			Registry: prometheus.NewRegistry(),
+		},
+	)
 
 	ch := make(chan []*targetgroup.Group)
 	ctx, cancel := context.WithCancel(context.Background())

discovery/scaleway/instance_test.go

@@ -55,12 +55,12 @@ api_url: %s
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 2, len(tg.Targets))
+	require.Len(t, tg.Targets, 2)
 
 	for i, lbls := range []model.LabelSet{
 		{
@@ -161,5 +161,5 @@ api_url: %s
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 }

discovery/scaleway/scaleway.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/scaleway/scaleway-sdk-go/scw"
@@ -160,7 +161,7 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 }
 
 func (c SDConfig) NewDiscoverer(options discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(&c, options.Logger)
+	return NewDiscovery(&c, options.Logger, options.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -177,17 +178,20 @@ func init() {
 // the Discoverer interface.
 type Discovery struct{}
 
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
 	r, err := newRefresher(conf)
 	if err != nil {
 		return nil, err
 	}
 
 	return refresh.NewDiscovery(
-		logger,
-		"scaleway",
-		time.Duration(conf.RefreshInterval),
-		r.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "scaleway",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: r.refresh,
+			Registry: reg,
+		},
 	), nil
 }
 

discovery/triton/triton.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/mwitkow/go-conntrack"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -74,7 +75,7 @@ func (*SDConfig) Name() string { return "triton" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return New(opts.Logger, c)
+	return New(opts.Logger, c, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -138,7 +139,7 @@ type Discovery struct {
 }
 
 // New returns a new Discovery which periodically refreshes its targets.
-func New(logger log.Logger, conf *SDConfig) (*Discovery, error) {
+func New(logger log.Logger, conf *SDConfig, reg prometheus.Registerer) (*Discovery, error) {
 	tls, err := config.NewTLSConfig(&conf.TLSConfig)
 	if err != nil {
 		return nil, err
@@ -159,10 +160,13 @@ func New(logger log.Logger, conf *SDConfig) (*Discovery, error) {
 		sdConfig: conf,
 	}
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"triton",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "triton",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/triton/triton_test.go

@@ -24,6 +24,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
@@ -79,7 +80,7 @@ var (
 )
 
 func newTritonDiscovery(c SDConfig) (*Discovery, error) {
-	return New(nil, &c)
+	return New(nil, &c, prometheus.NewRegistry())
 }
 
 func TestTritonSDNew(t *testing.T) {
@@ -155,7 +156,7 @@ func TestTritonSDRefreshMultipleTargets(t *testing.T) {
 
 	tgts := testTritonSDRefresh(t, conf, dstr)
 	require.NotNil(t, tgts)
-	require.Equal(t, 2, len(tgts))
+	require.Len(t, tgts, 2)
 }
 
 func TestTritonSDRefreshNoServer(t *testing.T) {
@@ -163,7 +164,7 @@ func TestTritonSDRefreshNoServer(t *testing.T) {
 
 	_, err := td.refresh(context.Background())
 	require.Error(t, err)
-	require.Equal(t, strings.Contains(err.Error(), "an error occurred when requesting targets from the discovery endpoint"), true)
+	require.True(t, strings.Contains(err.Error(), "an error occurred when requesting targets from the discovery endpoint"))
 }
 
 func TestTritonSDRefreshCancelled(t *testing.T) {
@@ -173,7 +174,7 @@ func TestTritonSDRefreshCancelled(t *testing.T) {
 	cancel()
 	_, err := td.refresh(ctx)
 	require.Error(t, err)
-	require.Equal(t, strings.Contains(err.Error(), context.Canceled.Error()), true)
+	require.True(t, strings.Contains(err.Error(), context.Canceled.Error()))
 }
 
 func TestTritonSDRefreshCNsUUIDOnly(t *testing.T) {
@@ -188,7 +189,7 @@ func TestTritonSDRefreshCNsUUIDOnly(t *testing.T) {
 
 	tgts := testTritonSDRefresh(t, cnconf, dstr)
 	require.NotNil(t, tgts)
-	require.Equal(t, 2, len(tgts))
+	require.Len(t, tgts, 2)
 }
 
 func TestTritonSDRefreshCNsWithHostname(t *testing.T) {
@@ -205,7 +206,7 @@ func TestTritonSDRefreshCNsWithHostname(t *testing.T) {
 
 	tgts := testTritonSDRefresh(t, cnconf, dstr)
 	require.NotNil(t, tgts)
-	require.Equal(t, 2, len(tgts))
+	require.Len(t, tgts, 2)
 }
 
 func testTritonSDRefresh(t *testing.T, c SDConfig, dstr string) []model.LabelSet {
@@ -235,7 +236,7 @@ func testTritonSDRefresh(t *testing.T, c SDConfig, dstr string) []model.LabelSet
 
 	tgs, err := td.refresh(context.Background())
 	require.NoError(t, err)
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 	tg := tgs[0]
 	require.NotNil(t, tg)
 

discovery/util.go

@@ -0,0 +1,72 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package discovery
+
+import (
+	"fmt"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// A utility to be used by implementations of discovery.Discoverer
+// which need to manage the lifetime of their metrics.
+type MetricRegisterer interface {
+	RegisterMetrics() error
+	UnregisterMetrics()
+}
+
+// metricRegistererImpl is an implementation of MetricRegisterer.
+type metricRegistererImpl struct {
+	reg     prometheus.Registerer
+	metrics []prometheus.Collector
+}
+
+var _ MetricRegisterer = &metricRegistererImpl{}
+
+// Creates an instance of a MetricRegisterer.
+// Typically called inside the implementation of the NewDiscoverer() method.
+func NewMetricRegisterer(reg prometheus.Registerer, metrics []prometheus.Collector) MetricRegisterer {
+	return &metricRegistererImpl{
+		reg:     reg,
+		metrics: metrics,
+	}
+}
+
+// RegisterMetrics registers the metrics with a Prometheus registerer.
+// If any metric fails to register, it will unregister all metrics that
+// were registered so far, and return an error.
+// Typically called at the start of the SD's Run() method.
+func (rh *metricRegistererImpl) RegisterMetrics() error {
+	for _, collector := range rh.metrics {
+		err := rh.reg.Register(collector)
+		if err != nil {
+			// Unregister all metrics that were registered so far.
+			// This is so that if RegisterMetrics() gets called again,
+			// there will not be an error due to a duplicate registration.
+			rh.UnregisterMetrics()
+
+			return fmt.Errorf("failed to register metric: %w", err)
+		}
+	}
+	return nil
+}
+
+// UnregisterMetrics unregisters the metrics from the same Prometheus
+// registerer which was used to register them.
+// Typically called at the end of the SD's Run() method by a defer statement.
+func (rh *metricRegistererImpl) UnregisterMetrics() {
+	for _, collector := range rh.metrics {
+		rh.reg.Unregister(collector)
+	}
+}

discovery/uyuni/uyuni.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/kolo/xmlrpc"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -115,7 +116,7 @@ func (*SDConfig) Name() string { return "uyuni" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -203,7 +204,7 @@ func getEndpointInfoForSystems(
 }
 
 // NewDiscovery returns a uyuni discovery for the given configuration.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	apiURL, err := url.Parse(conf.Server)
 	if err != nil {
 		return nil, err
@@ -227,10 +228,13 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"uyuni",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "uyuni",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/uyuni/uyuni_test.go

@@ -23,6 +23,8 @@ import (
 
 	"github.com/stretchr/testify/require"
 
+	"github.com/prometheus/client_golang/prometheus"
+
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -35,7 +37,7 @@ func testUpdateServices(respHandler http.HandlerFunc) ([]*targetgroup.Group, err
 		Server: ts.URL,
 	}
 
-	md, err := NewDiscovery(&conf, nil)
+	md, err := NewDiscovery(&conf, nil, prometheus.NewRegistry())
 	if err != nil {
 		return nil, err
 	}
@@ -55,7 +57,7 @@ func TestUyuniSDHandleError(t *testing.T) {
 	tgs, err := testUpdateServices(respHandler)
 
 	require.EqualError(t, err, errTesting)
-	require.Equal(t, len(tgs), 0)
+	require.Empty(t, tgs)
 }
 
 func TestUyuniSDLogin(t *testing.T) {
@@ -87,7 +89,7 @@ func TestUyuniSDLogin(t *testing.T) {
 	tgs, err := testUpdateServices(respHandler)
 
 	require.EqualError(t, err, errTesting)
-	require.Equal(t, len(tgs), 0)
+	require.Empty(t, tgs)
 }
 
 func TestUyuniSDSkipLogin(t *testing.T) {
@@ -108,7 +110,7 @@ func TestUyuniSDSkipLogin(t *testing.T) {
 		Server: ts.URL,
 	}
 
-	md, err := NewDiscovery(&conf, nil)
+	md, err := NewDiscovery(&conf, nil, prometheus.NewRegistry())
 	if err != nil {
 		t.Error(err)
 	}
@@ -119,5 +121,5 @@ func TestUyuniSDSkipLogin(t *testing.T) {
 	tgs, err := md.refresh(context.Background())
 
 	require.EqualError(t, err, errTesting)
-	require.Equal(t, len(tgs), 0)
+	require.Empty(t, tgs)
 }

discovery/vultr/vultr.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/version"
@@ -78,7 +79,7 @@ func (*SDConfig) Name() string { return "vultr" }
 
 // NewDiscoverer returns a Discoverer for the Config.
 func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(c, opts.Logger)
+	return NewDiscovery(c, opts.Logger, opts.Registerer)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -106,7 +107,7 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
 	d := &Discovery{
 		port: conf.Port,
 	}
@@ -128,10 +129,13 @@ func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
 	}
 
 	d.Discovery = refresh.NewDiscovery(
-		logger,
-		"vultr",
-		time.Duration(conf.RefreshInterval),
-		d.refresh,
+		refresh.Options{
+			Logger:   logger,
+			Mech:     "vultr",
+			Interval: time.Duration(conf.RefreshInterval),
+			RefreshF: d.refresh,
+			Registry: reg,
+		},
 	)
 	return d, nil
 }

discovery/vultr/vultr_test.go

@@ -20,6 +20,7 @@ import (
 	"testing"
 
 	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 )
@@ -46,7 +47,7 @@ func TestVultrSDRefresh(t *testing.T) {
 
 	cfg := DefaultSDConfig
 	cfg.HTTPClientConfig.BearerToken = APIKey
-	d, err := NewDiscovery(&cfg, log.NewNopLogger())
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
 	require.NoError(t, err)
 	endpoint, err := url.Parse(sdMock.Mock.Endpoint())
 	require.NoError(t, err)
@@ -56,12 +57,12 @@ func TestVultrSDRefresh(t *testing.T) {
 	tgs, err := d.refresh(ctx)
 	require.NoError(t, err)
 
-	require.Equal(t, 1, len(tgs))
+	require.Len(t, tgs, 1)
 
 	tg := tgs[0]
 	require.NotNil(t, tg)
 	require.NotNil(t, tg.Targets)
-	require.Equal(t, 3, len(tg.Targets))
+	require.Len(t, tg.Targets, 3)
 
 	for i, k := range []model.LabelSet{
 		{

discovery/xds/client_test.go

@@ -53,14 +53,14 @@ func TestMakeXDSResourceHttpEndpointEmptyServerURLScheme(t *testing.T) {
 
 	require.Empty(t, endpointURL)
 	require.Error(t, err)
-	require.Equal(t, err.Error(), "invalid xDS server URL")
+	require.Equal(t, "invalid xDS server URL", err.Error())
 }
 
 func TestMakeXDSResourceHttpEndpointEmptyServerURLHost(t *testing.T) {
 	endpointURL, err := makeXDSResourceHTTPEndpointURL(ProtocolV3, urlMustParse("grpc://127.0.0.1"), "monitoring")
 
 	require.Empty(t, endpointURL)
-	require.NotNil(t, err)
+	require.Error(t, err)
 	require.Contains(t, err.Error(), "must be either 'http' or 'https'")
 }
 
@@ -68,7 +68,7 @@ func TestMakeXDSResourceHttpEndpoint(t *testing.T) {
 	endpointURL, err := makeXDSResourceHTTPEndpointURL(ProtocolV3, urlMustParse("http://127.0.0.1:5000"), "monitoring")
 
 	require.NoError(t, err)
-	require.Equal(t, endpointURL.String(), "http://127.0.0.1:5000/v3/discovery:monitoring")
+	require.Equal(t, "http://127.0.0.1:5000/v3/discovery:monitoring", endpointURL.String())
 }
 
 func TestCreateNewHTTPResourceClient(t *testing.T) {
@@ -89,8 +89,8 @@ func TestCreateNewHTTPResourceClient(t *testing.T) {
 
 	require.NoError(t, err)
 
-	require.Equal(t, client.endpoint, "http://127.0.0.1:5000/v3/discovery:monitoring?param1=v1")
-	require.Equal(t, client.client.Timeout, 1*time.Minute)
+	require.Equal(t, "http://127.0.0.1:5000/v3/discovery:monitoring?param1=v1", client.endpoint)
+	require.Equal(t, 1*time.Minute, client.client.Timeout)
 }
 
 func createTestHTTPResourceClient(t *testing.T, conf *HTTPResourceClientConfig, protocolVersion ProtocolVersion, responder discoveryResponder) (*HTTPResourceClient, func()) {
@@ -138,7 +138,7 @@ func TestHTTPResourceClientFetchFullResponse(t *testing.T) {
 	require.NotNil(t, res)
 
 	require.Equal(t, client.ResourceTypeURL(), res.TypeUrl)
-	require.Len(t, res.Resources, 0)
+	require.Empty(t, res.Resources)
 	require.Equal(t, "abc", client.latestNonce, "Nonce not cached")
 	require.Equal(t, "1", client.latestVersion, "Version not cached")
 

discovery/xds/kuma.go

@@ -30,35 +30,12 @@ import (
 	"github.com/prometheus/prometheus/util/strutil"
 )
 
-var (
-	// DefaultKumaSDConfig is the default Kuma MADS SD configuration.
-	DefaultKumaSDConfig = KumaSDConfig{
-		HTTPClientConfig: config.DefaultHTTPClientConfig,
-		RefreshInterval:  model.Duration(15 * time.Second),
-		FetchTimeout:     model.Duration(2 * time.Minute),
-	}
-
-	kumaFetchFailuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Namespace: namespace,
-			Name:      "sd_kuma_fetch_failures_total",
-			Help:      "The number of Kuma MADS fetch call failures.",
-		})
-	kumaFetchSkipUpdateCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Namespace: namespace,
-			Name:      "sd_kuma_fetch_skipped_updates_total",
-			Help:      "The number of Kuma MADS fetch calls that result in no updates to the targets.",
-		})
-	kumaFetchDuration = prometheus.NewSummary(
-		prometheus.SummaryOpts{
-			Namespace:  namespace,
-			Name:       "sd_kuma_fetch_duration_seconds",
-			Help:       "The duration of a Kuma MADS fetch call.",
-			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
-		},
-	)
-)
+// DefaultKumaSDConfig is the default Kuma MADS SD configuration.
+var DefaultKumaSDConfig = KumaSDConfig{
+	HTTPClientConfig: config.DefaultHTTPClientConfig,
+	RefreshInterval:  model.Duration(15 * time.Second),
+	FetchTimeout:     model.Duration(2 * time.Minute),
+}
 
 const (
 	// kumaMetaLabelPrefix is the meta prefix used for all kuma meta labels.
@@ -120,7 +97,7 @@ func (c *KumaSDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discover
 		logger = log.NewNopLogger()
 	}
 
-	return NewKumaHTTPDiscovery(c, logger)
+	return NewKumaHTTPDiscovery(c, logger, opts.Registerer)
 }
 
 func convertKumaV1MonitoringAssignment(assignment *MonitoringAssignment) []model.LabelSet {
@@ -176,12 +153,16 @@ func kumaMadsV1ResourceParser(resources []*anypb.Any, typeURL string) ([]model.L
 	return targets, nil
 }
 
-func NewKumaHTTPDiscovery(conf *KumaSDConfig, logger log.Logger) (discovery.Discoverer, error) {
+func NewKumaHTTPDiscovery(conf *KumaSDConfig, logger log.Logger, reg prometheus.Registerer) (discovery.Discoverer, error) {
 	// Default to "prometheus" if hostname is unavailable.
-	clientID, err := osutil.GetFQDN()
-	if err != nil {
-		level.Debug(logger).Log("msg", "error getting FQDN", "err", err)
-		clientID = "prometheus"
+	clientID := conf.ClientID
+	if clientID == "" {
+		var err error
+		clientID, err = osutil.GetFQDN()
+		if err != nil {
+			level.Debug(logger).Log("msg", "error getting FQDN", "err", err)
+			clientID = "prometheus"
+		}
 	}
 
 	clientConfig := &HTTPResourceClientConfig{
@@ -203,15 +184,41 @@ func NewKumaHTTPDiscovery(conf *KumaSDConfig, logger log.Logger) (discovery.Disc
 	}
 
 	d := &fetchDiscovery{
-		client:               client,
-		logger:               logger,
-		refreshInterval:      time.Duration(conf.RefreshInterval),
-		source:               "kuma",
-		parseResources:       kumaMadsV1ResourceParser,
-		fetchFailuresCount:   kumaFetchFailuresCount,
-		fetchSkipUpdateCount: kumaFetchSkipUpdateCount,
-		fetchDuration:        kumaFetchDuration,
+		client:          client,
+		logger:          logger,
+		refreshInterval: time.Duration(conf.RefreshInterval),
+		source:          "kuma",
+		parseResources:  kumaMadsV1ResourceParser,
+		fetchFailuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Namespace: namespace,
+				Name:      "sd_kuma_fetch_failures_total",
+				Help:      "The number of Kuma MADS fetch call failures.",
+			}),
+		fetchSkipUpdateCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Namespace: namespace,
+				Name:      "sd_kuma_fetch_skipped_updates_total",
+				Help:      "The number of Kuma MADS fetch calls that result in no updates to the targets.",
+			}),
+		fetchDuration: prometheus.NewSummary(
+			prometheus.SummaryOpts{
+				Namespace:  namespace,
+				Name:       "sd_kuma_fetch_duration_seconds",
+				Help:       "The duration of a Kuma MADS fetch call.",
+				Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+			},
+		),
 	}
 
+	d.metricRegisterer = discovery.NewMetricRegisterer(
+		reg,
+		[]prometheus.Collector{
+			d.fetchFailuresCount,
+			d.fetchSkipUpdateCount,
+			d.fetchDuration,
+		},
+	)
+
 	return d, nil
 }

discovery/xds/kuma_test.go

@@ -21,6 +21,7 @@ import (
 	"time"
 
 	v3 "github.com/envoyproxy/go-control-plane/envoy/service/discovery/v3"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/protobuf/proto"
@@ -107,7 +108,7 @@ func getKumaMadsV1DiscoveryResponse(resources ...*MonitoringAssignment) (*v3.Dis
 }
 
 func newKumaTestHTTPDiscovery(c KumaSDConfig) (*fetchDiscovery, error) {
-	kd, err := NewKumaHTTPDiscovery(&c, nopLogger)
+	kd, err := NewKumaHTTPDiscovery(&c, nopLogger, prometheus.NewRegistry())
 	if err != nil {
 		return nil, err
 	}
@@ -129,7 +130,7 @@ func TestKumaMadsV1ResourceParserInvalidTypeURL(t *testing.T) {
 func TestKumaMadsV1ResourceParserEmptySlice(t *testing.T) {
 	resources := make([]*anypb.Any, 0)
 	groups, err := kumaMadsV1ResourceParser(resources, KumaMadsV1ResourceTypeURL)
-	require.Len(t, groups, 0)
+	require.Empty(t, groups)
 	require.NoError(t, err)
 }
 
@@ -204,7 +205,7 @@ func TestNewKumaHTTPDiscovery(t *testing.T) {
 	require.True(t, ok)
 	require.Equal(t, kumaConf.Server, resClient.Server())
 	require.Equal(t, KumaMadsV1ResourceTypeURL, resClient.ResourceTypeURL())
-	require.NotEmpty(t, resClient.ID())
+	require.Equal(t, kumaConf.ClientID, resClient.ID())
 	require.Equal(t, KumaMadsV1ResourceType, resClient.config.ResourceType)
 }
 

discovery/xds/xds.go

@@ -55,6 +55,7 @@ type SDConfig struct {
 	RefreshInterval  model.Duration          `yaml:"refresh_interval,omitempty"`
 	FetchTimeout     model.Duration          `yaml:"fetch_timeout,omitempty"`
 	Server           string                  `yaml:"server,omitempty"`
+	ClientID         string                  `yaml:"client_id,omitempty"`
 }
 
 // mustRegisterMessage registers the provided message type in the typeRegistry, and panics
@@ -69,9 +70,6 @@ func init() {
 	// Register top-level SD Configs.
 	discovery.RegisterConfig(&KumaSDConfig{})
 
-	// Register metrics.
-	prometheus.MustRegister(kumaFetchDuration, kumaFetchSkipUpdateCount, kumaFetchFailuresCount)
-
 	// Register protobuf types that need to be marshalled/ unmarshalled.
 	mustRegisterMessage(protoTypes, (&v3.DiscoveryRequest{}).ProtoReflect().Type())
 	mustRegisterMessage(protoTypes, (&v3.DiscoveryResponse{}).ProtoReflect().Type())
@@ -109,12 +107,20 @@ type fetchDiscovery struct {
 	parseResources resourceParser
 	logger         log.Logger
 
-	fetchDuration        prometheus.Observer
+	fetchDuration        prometheus.Summary
 	fetchSkipUpdateCount prometheus.Counter
 	fetchFailuresCount   prometheus.Counter
+
+	metricRegisterer discovery.MetricRegisterer
 }
 
 func (d *fetchDiscovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
+	err := d.metricRegisterer.RegisterMetrics()
+	if err != nil {
+		level.Error(d.logger).Log("msg", "Unable to register metrics", "err", err.Error())
+		return
+	}
+	defer d.metricRegisterer.UnregisterMetrics()
 	defer d.client.Close()
 
 	ticker := time.NewTicker(d.refreshInterval)