SD Managers taking over responsibility for registration of debug metrics (#13375)

SD Managers take over responsibility for SD metrics registration

---------

Signed-off-by: Paulin Todev <paulin.todev@gmail.com>
Signed-off-by: Björn Rabenstein <github@rabenste.in>
Co-authored-by: Björn Rabenstein <github@rabenste.in>

cmd/prometheus/main.go

@@ -644,9 +644,16 @@ func main() {
 		level.Error(logger).Log("msg", "failed to register Kubernetes client metrics", "err", err)
 		os.Exit(1)
 	}
+
+	sdMetrics, err := discovery.CreateAndRegisterSDMetrics(prometheus.DefaultRegisterer)
+	if err != nil {
+		level.Error(logger).Log("msg", "failed to register service discovery metrics", "err", err)
+		os.Exit(1)
+	}
+
 	if cfg.enableNewSDManager {
 		{
-			discMgr := discovery.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), prometheus.DefaultRegisterer, discovery.Name("scrape"))
+			discMgr := discovery.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), prometheus.DefaultRegisterer, sdMetrics, discovery.Name("scrape"))
 			if discMgr == nil {
 				level.Error(logger).Log("msg", "failed to create a discovery manager scrape")
 				os.Exit(1)
@@ -655,7 +662,7 @@ func main() {
 		}
 
 		{
-			discMgr := discovery.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), prometheus.DefaultRegisterer, discovery.Name("notify"))
+			discMgr := discovery.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), prometheus.DefaultRegisterer, sdMetrics, discovery.Name("notify"))
 			if discMgr == nil {
 				level.Error(logger).Log("msg", "failed to create a discovery manager notify")
 				os.Exit(1)
@@ -664,7 +671,7 @@ func main() {
 		}
 	} else {
 		{
-			discMgr := legacymanager.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), prometheus.DefaultRegisterer, legacymanager.Name("scrape"))
+			discMgr := legacymanager.NewManager(ctxScrape, log.With(logger, "component", "discovery manager scrape"), prometheus.DefaultRegisterer, sdMetrics, legacymanager.Name("scrape"))
 			if discMgr == nil {
 				level.Error(logger).Log("msg", "failed to create a discovery manager scrape")
 				os.Exit(1)
@@ -673,7 +680,7 @@ func main() {
 		}
 
 		{
-			discMgr := legacymanager.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), prometheus.DefaultRegisterer, legacymanager.Name("notify"))
+			discMgr := legacymanager.NewManager(ctxNotify, log.With(logger, "component", "discovery manager notify"), prometheus.DefaultRegisterer, sdMetrics, legacymanager.Name("notify"))
 			if discMgr == nil {
 				level.Error(logger).Log("msg", "failed to create a discovery manager notify")
 				os.Exit(1)

cmd/promtool/sd.go

@@ -78,12 +78,25 @@ func CheckSD(sdConfigFiles, sdJobName string, sdTimeout time.Duration, noDefault
 	defer cancel()
 
 	for _, cfg := range scrapeConfig.ServiceDiscoveryConfigs {
-		d, err := cfg.NewDiscoverer(discovery.DiscovererOptions{Logger: logger, Registerer: registerer})
+		reg := prometheus.NewRegistry()
+		refreshMetrics := discovery.NewRefreshMetrics(reg)
+		metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+		err := metrics.Register()
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "Could not register service discovery metrics", err)
+			return failureExitCode
+		}
+
+		d, err := cfg.NewDiscoverer(discovery.DiscovererOptions{Logger: logger, Metrics: metrics})
 		if err != nil {
 			fmt.Fprintln(os.Stderr, "Could not create new discoverer", err)
 			return failureExitCode
 		}
-		go d.Run(ctx, targetGroupChan)
+		go func() {
+			d.Run(ctx, targetGroupChan)
+			metrics.Unregister()
+			refreshMetrics.Unregister()
+		}()
 	}
 
 	var targetGroups []*targetgroup.Group

discovery/aws/ec2.go

@@ -97,12 +97,19 @@ type EC2SDConfig struct {
 	HTTPClientConfig config.HTTPClientConfig `yaml:",inline"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*EC2SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &ec2Metrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the EC2 Config.
 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, opts.Registerer), nil
+	return NewEC2Discovery(c, opts.Logger, opts.Metrics)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface for the EC2 Config.
@@ -148,7 +155,12 @@ type EC2Discovery struct {
 }
 
 // NewEC2Discovery returns a new EC2Discovery which periodically refreshes its targets.
-func NewEC2Discovery(conf *EC2SDConfig, logger log.Logger, reg prometheus.Registerer) *EC2Discovery {
+func NewEC2Discovery(conf *EC2SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*EC2Discovery, error) {
+	m, ok := metrics.(*ec2Metrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -162,10 +174,10 @@ func NewEC2Discovery(conf *EC2SDConfig, logger log.Logger, reg prometheus.Regist
 			Mech:                "ec2",
 			Interval:            time.Duration(d.cfg.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
-	return d
+	return d, nil
 }
 
 func (d *EC2Discovery) ec2Client(context.Context) (*ec2.EC2, error) {

discovery/aws/lightsail.go

@@ -80,12 +80,19 @@ type LightsailSDConfig struct {
 	HTTPClientConfig config.HTTPClientConfig `yaml:",inline"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*LightsailSDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &lightsailMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Lightsail Config.
 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, opts.Registerer), nil
+	return NewLightsailDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface for the Lightsail Config.
@@ -122,10 +129,16 @@ type LightsailDiscovery struct {
 }
 
 // NewLightsailDiscovery returns a new LightsailDiscovery which periodically refreshes its targets.
-func NewLightsailDiscovery(conf *LightsailSDConfig, logger log.Logger, reg prometheus.Registerer) *LightsailDiscovery {
+func NewLightsailDiscovery(conf *LightsailSDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*LightsailDiscovery, error) {
+	m, ok := metrics.(*lightsailMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
+
 	d := &LightsailDiscovery{
 		cfg: conf,
 	}
@@ -135,10 +148,10 @@ func NewLightsailDiscovery(conf *LightsailSDConfig, logger log.Logger, reg prome
 			Mech:                "lightsail",
 			Interval:            time.Duration(d.cfg.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
-	return d
+	return d, nil
 }
 
 func (d *LightsailDiscovery) lightsailClient() (*lightsail.Lightsail, error) {

discovery/aws/metrics_ec2.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 aws
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+type ec2Metrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+var _ discovery.DiscovererMetrics = (*ec2Metrics)(nil)
+
+// Register implements discovery.DiscovererMetrics.
+func (m *ec2Metrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *ec2Metrics) Unregister() {}

discovery/aws/metrics_lightsail.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 aws
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+type lightsailMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+var _ discovery.DiscovererMetrics = (*lightsailMetrics)(nil)
+
+// Register implements discovery.DiscovererMetrics.
+func (m *lightsailMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *lightsailMetrics) Unregister() {}

discovery/azure/azure.go

@@ -120,12 +120,17 @@ type SDConfig struct {
 	HTTPClientConfig config_util.HTTPClientConfig `yaml:",inline"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 func validateAuthParam(param, name string) error {
@@ -172,12 +177,16 @@ type Discovery struct {
 	cfg     *SDConfig
 	port    int
 	cache   *cache.Cache[string, *armnetwork.Interface]
-	failuresCount prometheus.Counter
-	cacheHitCount prometheus.Counter
+	metrics *azureMetrics
 }
 
 // NewDiscovery returns a new AzureDiscovery which periodically refreshes its targets.
-func NewDiscovery(cfg *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(cfg *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*azureMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -187,16 +196,7 @@ func NewDiscovery(cfg *SDConfig, logger log.Logger, reg prometheus.Registerer) (
 		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.",
-			}),
+		metrics: m,
 	}
 
 	d.Discovery = refresh.NewDiscovery(
@@ -205,8 +205,7 @@ func NewDiscovery(cfg *SDConfig, logger log.Logger, reg prometheus.Registerer) (
 			Mech:                "azure",
 			Interval:            time.Duration(cfg.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
-			Metrics:  []prometheus.Collector{d.failuresCount, d.cacheHitCount},
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 
@@ -333,14 +332,14 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 
 	client, err := createAzureClient(*d.cfg)
 	if err != nil {
-		d.failuresCount.Inc()
+		d.metrics.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 {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, fmt.Errorf("could not get virtual machines: %w", err)
 	}
 
@@ -349,14 +348,14 @@ 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 {
-		d.failuresCount.Inc()
+		d.metrics.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 {
-			d.failuresCount.Inc()
+			d.metrics.failuresCount.Inc()
 			return nil, fmt.Errorf("could not get virtual machine scale set vms: %w", err)
 		}
 		machines = append(machines, scaleSetVms...)
@@ -407,7 +406,7 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 				var networkInterface *armnetwork.Interface
 				if v, ok := d.getFromCache(nicID); ok {
 					networkInterface = v
-					d.cacheHitCount.Add(1)
+					d.metrics.cacheHitCount.Add(1)
 				} else {
 					if vm.ScaleSet == "" {
 						networkInterface, err = client.getVMNetworkInterfaceByID(ctx, nicID)
@@ -480,7 +479,7 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 	var tg targetgroup.Group
 	for tgt := range ch {
 		if tgt.err != nil {
-			d.failuresCount.Inc()
+			d.metrics.failuresCount.Inc()
 			return nil, fmt.Errorf("unable to complete Azure service discovery: %w", tgt.err)
 		}
 		if tgt.labelSet != nil {

discovery/azure/metrics.go

@@ -0,0 +1,64 @@
+// Copyright 2015 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 azure
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*azureMetrics)(nil)
+
+type azureMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+
+	failuresCount prometheus.Counter
+	cacheHitCount prometheus.Counter
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &azureMetrics{
+		refreshMetrics: rmi,
+		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.",
+			}),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.failuresCount,
+		m.cacheHitCount,
+	})
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *azureMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *azureMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/consul/consul.go

@@ -119,12 +119,17 @@ type SDConfig struct {
 	HTTPClientConfig config.HTTPClientConfig `yaml:",inline"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -173,15 +178,16 @@ type Discovery struct {
 	refreshInterval  time.Duration
 	finalizer        func()
 	logger           log.Logger
-	rpcFailuresCount    prometheus.Counter
-	rpcDuration         *prometheus.SummaryVec
-	servicesRPCDuration prometheus.Observer
-	serviceRPCDuration  prometheus.Observer
-	metricRegisterer    discovery.MetricRegisterer
+	metrics          *consulMetrics
 }
 
 // NewDiscovery returns a new Discovery for the given config.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*consulMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -219,35 +225,9 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 		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"},
-		),
+		metrics:          m,
 	}
 
-	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
 }
 
@@ -303,7 +283,7 @@ 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)
-		d.rpcFailuresCount.Inc()
+		d.metrics.rpcFailuresCount.Inc()
 		return err
 	}
 
@@ -344,13 +324,6 @@ 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()
 	}
@@ -399,7 +372,7 @@ 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)
-	d.servicesRPCDuration.Observe(elapsed.Seconds())
+	d.metrics.servicesRPCDuration.Observe(elapsed.Seconds())
 
 	// Check the context before in order to exit early.
 	select {
@@ -410,7 +383,7 @@ 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)
-		d.rpcFailuresCount.Inc()
+		d.metrics.rpcFailuresCount.Inc()
 		time.Sleep(retryInterval)
 		return
 	}
@@ -490,8 +463,8 @@ func (d *Discovery) watchService(ctx context.Context, ch chan<- []*targetgroup.G
 		},
 		tagSeparator:       d.tagSeparator,
 		logger:             d.logger,
-		rpcFailuresCount:   d.rpcFailuresCount,
-		serviceRPCDuration: d.serviceRPCDuration,
+		rpcFailuresCount:   d.metrics.rpcFailuresCount,
+		serviceRPCDuration: d.metrics.serviceRPCDuration,
 	}
 
 	go func() {

discovery/consul/consul_test.go

@@ -29,6 +29,7 @@ import (
 	"go.uber.org/goleak"
 	"gopkg.in/yaml.v2"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -36,11 +37,25 @@ func TestMain(m *testing.M) {
 	goleak.VerifyTestMain(m)
 }
 
+// TODO: Add ability to unregister metrics?
+func NewTestMetrics(t *testing.T, conf discovery.Config, reg prometheus.Registerer) discovery.DiscovererMetrics {
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	require.NoError(t, refreshMetrics.Register())
+
+	metrics := conf.NewDiscovererMetrics(prometheus.NewRegistry(), refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	return metrics
+}
+
 func TestConfiguredService(t *testing.T) {
 	conf := &SDConfig{
 		Services: []string{"configuredServiceName"},
 	}
-	consulDiscovery, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
+
+	metrics := NewTestMetrics(t, conf, prometheus.NewRegistry())
+
+	consulDiscovery, err := NewDiscovery(conf, nil, metrics)
 	if err != nil {
 		t.Errorf("Unexpected error when initializing discovery %v", err)
 	}
@@ -57,7 +72,10 @@ func TestConfiguredServiceWithTag(t *testing.T) {
 		Services:    []string{"configuredServiceName"},
 		ServiceTags: []string{"http"},
 	}
-	consulDiscovery, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
+
+	metrics := NewTestMetrics(t, conf, prometheus.NewRegistry())
+
+	consulDiscovery, err := NewDiscovery(conf, nil, metrics)
 	if err != nil {
 		t.Errorf("Unexpected error when initializing discovery %v", err)
 	}
@@ -152,7 +170,9 @@ func TestConfiguredServiceWithTags(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		consulDiscovery, err := NewDiscovery(tc.conf, nil, prometheus.NewRegistry())
+		metrics := NewTestMetrics(t, tc.conf, prometheus.NewRegistry())
+
+		consulDiscovery, err := NewDiscovery(tc.conf, nil, metrics)
 		if err != nil {
 			t.Errorf("Unexpected error when initializing discovery %v", err)
 		}
@@ -160,13 +180,15 @@ func TestConfiguredServiceWithTags(t *testing.T) {
 		if ret != tc.shouldWatch {
 			t.Errorf("Expected should watch? %t, got %t. Watched service and tags: %s %+v, input was %s %+v", tc.shouldWatch, ret, tc.conf.Services, tc.conf.ServiceTags, tc.serviceName, tc.serviceTags)
 		}
-
 	}
 }
 
 func TestNonConfiguredService(t *testing.T) {
 	conf := &SDConfig{}
-	consulDiscovery, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
+
+	metrics := NewTestMetrics(t, conf, prometheus.NewRegistry())
+
+	consulDiscovery, err := NewDiscovery(conf, nil, metrics)
 	if err != nil {
 		t.Errorf("Unexpected error when initializing discovery %v", err)
 	}
@@ -263,7 +285,10 @@ func newServer(t *testing.T) (*httptest.Server, *SDConfig) {
 
 func newDiscovery(t *testing.T, config *SDConfig) *Discovery {
 	logger := log.NewNopLogger()
-	d, err := NewDiscovery(config, logger, prometheus.NewRegistry())
+
+	metrics := NewTestMetrics(t, config, prometheus.NewRegistry())
+
+	d, err := NewDiscovery(config, logger, metrics)
 	require.NoError(t, err)
 	return d
 }

discovery/consul/metrics.go

@@ -0,0 +1,73 @@
+// Copyright 2015 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 consul
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*consulMetrics)(nil)
+
+type consulMetrics struct {
+	rpcFailuresCount prometheus.Counter
+	rpcDuration      *prometheus.SummaryVec
+
+	servicesRPCDuration prometheus.Observer
+	serviceRPCDuration  prometheus.Observer
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &consulMetrics{
+		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"},
+		),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.rpcFailuresCount,
+		m.rpcDuration,
+	})
+
+	// Initialize metric vectors.
+	m.servicesRPCDuration = m.rpcDuration.WithLabelValues("catalog", "services")
+	m.serviceRPCDuration = m.rpcDuration.WithLabelValues("catalog", "service")
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *consulMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *consulMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/digitalocean/digitalocean.go

@@ -63,6 +63,13 @@ func init() {
 	discovery.RegisterConfig(&SDConfig{})
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &digitaloceanMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // SDConfig is the configuration for DigitalOcean based service discovery.
 type SDConfig struct {
 	HTTPClientConfig config.HTTPClientConfig `yaml:",inline"`
@@ -76,7 +83,7 @@ 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -104,7 +111,12 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*digitaloceanMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	d := &Discovery{
 		port: conf.Port,
 	}
@@ -131,7 +143,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "digitalocean",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/digitalocean/digitalocean_test.go

@@ -23,6 +23,8 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 type DigitalOceanSDTestSuite struct {
@@ -47,7 +49,15 @@ func TestDigitalOceanSDRefresh(t *testing.T) {
 
 	cfg := DefaultSDConfig
 	cfg.HTTPClientConfig.BearerToken = tokenID
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 	endpoint, err := url.Parse(sdmock.Mock.Endpoint())
 	require.NoError(t, err)

discovery/digitalocean/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 digitalocean
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*digitaloceanMetrics)(nil)
+
+type digitaloceanMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *digitaloceanMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *digitaloceanMetrics) Unregister() {}

discovery/discoverer_metrics_noop.go

@@ -0,0 +1,28 @@
+// Copyright 2015 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
+
+// Create a dummy metrics struct, because this SD doesn't have any metrics.
+type NoopDiscovererMetrics struct{}
+
+var _ DiscovererMetrics = (*NoopDiscovererMetrics)(nil)
+
+// Register implements discovery.DiscovererMetrics.
+func (*NoopDiscovererMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (*NoopDiscovererMetrics) Unregister() {
+}

discovery/discovery.go

@@ -39,24 +39,47 @@ type Discoverer interface {
 	Run(ctx context.Context, up chan<- []*targetgroup.Group)
 }
 
+// Internal metrics of service discovery mechanisms.
+type DiscovererMetrics interface {
+	Register() error
+	Unregister()
+}
+
 // DiscovererOptions provides options for a Discoverer.
 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
+	Metrics DiscovererMetrics
 
 	// Extra HTTP client options to expose to Discoverers. This field may be
 	// ignored; Discoverer implementations must opt-in to reading it.
 	HTTPClientOptions []config.HTTPClientOption
 }
 
+// Metrics used by the "refresh" package.
+// We define them here in the "discovery" package in order to avoid a cyclic dependency between
+// "discovery" and "refresh".
+type RefreshMetrics struct {
+	Failures prometheus.Counter
+	Duration prometheus.Observer
+}
+
+// Instantiate the metrics used by the "refresh" package.
+type RefreshMetricsInstantiator interface {
+	Instantiate(mech string) *RefreshMetrics
+}
+
+// An interface for registering, unregistering, and instantiating metrics for the "refresh" package.
+// Refresh metrics are registered and unregistered outside of the service discovery mechanism.
+// This is so that the same metrics can be reused across different service discovery mechanisms.
+// To manage refresh metrics inside the SD mechanism, we'd need to use const labels which are
+// specific to that SD. However, doing so would also expose too many unused metrics on
+// the Prometheus /metrics endpoint.
+type RefreshMetricsManager interface {
+	DiscovererMetrics
+	RefreshMetricsInstantiator
+}
+
 // A Config provides the configuration and constructor for a Discoverer.
 type Config interface {
 	// Name returns the name of the discovery mechanism.
@@ -65,6 +88,9 @@ type Config interface {
 	// NewDiscoverer returns a Discoverer for the Config
 	// with the given DiscovererOptions.
 	NewDiscoverer(DiscovererOptions) (Discoverer, error)
+
+	// NewDiscovererMetrics returns the metrics used by the service discovery.
+	NewDiscovererMetrics(prometheus.Registerer, RefreshMetricsInstantiator) DiscovererMetrics
 }
 
 // Configs is a slice of Config values that uses custom YAML marshaling and unmarshaling
@@ -119,6 +145,11 @@ func (c StaticConfig) NewDiscoverer(DiscovererOptions) (Discoverer, error) {
 	return staticDiscoverer(c), nil
 }
 
+// No metrics are needed for this service discovery mechanism.
+func (c StaticConfig) NewDiscovererMetrics(prometheus.Registerer, RefreshMetricsInstantiator) DiscovererMetrics {
+	return &NoopDiscovererMetrics{}
+}
+
 type staticDiscoverer []*targetgroup.Group
 
 func (c staticDiscoverer) Run(ctx context.Context, up chan<- []*targetgroup.Group) {

discovery/dns/dns.go

@@ -67,12 +67,17 @@ type SDConfig struct {
 	Port            int            `yaml:"port"` // Ignored for SRV records
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(*c, opts.Logger, opts.Metrics)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
@@ -106,14 +111,18 @@ type Discovery struct {
 	port    int
 	qtype   uint16
 	logger  log.Logger
-	dnsSDLookupsCount        prometheus.Counter
-	dnsSDLookupFailuresCount prometheus.Counter
+	metrics *dnsMetrics
 
 	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, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*dnsMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -137,18 +146,7 @@ func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (
 		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.",
-			}),
+		metrics:  m,
 	}
 
 	d.Discovery = refresh.NewDiscovery(
@@ -157,8 +155,7 @@ func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (
 			Mech:                "dns",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: prometheus.NewRegistry(),
-			Metrics:  []prometheus.Collector{d.dnsSDLookupsCount, d.dnsSDLookupFailuresCount},
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 
@@ -195,9 +192,9 @@ 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)
-	d.dnsSDLookupsCount.Inc()
+	d.metrics.dnsSDLookupsCount.Inc()
 	if err != nil {
-		d.dnsSDLookupFailuresCount.Inc()
+		d.metrics.dnsSDLookupFailuresCount.Inc()
 		return err
 	}
 

discovery/dns/dns_test.go

@@ -28,6 +28,7 @@ import (
 	"go.uber.org/goleak"
 	"gopkg.in/yaml.v2"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -253,13 +254,21 @@ func TestDNS(t *testing.T) {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
-			sd, err := NewDiscovery(tc.config, nil, prometheus.NewRegistry())
+
+			reg := prometheus.NewRegistry()
+			refreshMetrics := discovery.NewRefreshMetrics(reg)
+			metrics := tc.config.NewDiscovererMetrics(reg, refreshMetrics)
+			require.NoError(t, metrics.Register())
+
+			sd, err := NewDiscovery(tc.config, nil, metrics)
 			require.NoError(t, err)
 			sd.lookupFn = tc.lookup
 
 			tgs, err := sd.refresh(context.Background())
 			require.NoError(t, err)
 			require.Equal(t, tc.expected, tgs)
+
+			metrics.Unregister()
 		})
 	}
 }

discovery/dns/metrics.go

@@ -0,0 +1,66 @@
+// Copyright 2015 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 dns
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*dnsMetrics)(nil)
+
+type dnsMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+
+	dnsSDLookupsCount        prometheus.Counter
+	dnsSDLookupFailuresCount prometheus.Counter
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &dnsMetrics{
+		refreshMetrics: rmi,
+		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.",
+			}),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.dnsSDLookupsCount,
+		m.dnsSDLookupFailuresCount,
+	})
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *dnsMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *dnsMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/eureka/eureka.go

@@ -16,6 +16,7 @@ package eureka
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net"
 	"net/http"
 	"net/url"
@@ -76,12 +77,19 @@ type SDConfig struct {
 	RefreshInterval  model.Duration          `yaml:"refresh_interval,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &eurekaMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -118,7 +126,12 @@ type Discovery struct {
 }
 
 // NewDiscovery creates a new Eureka discovery for the given role.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*eurekaMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "eureka_sd")
 	if err != nil {
 		return nil, err
@@ -134,7 +147,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "eureka",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/eureka/eureka_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -36,7 +37,17 @@ func testUpdateServices(respHandler http.HandlerFunc) ([]*targetgroup.Group, err
 		Server: ts.URL,
 	}
 
-	md, err := NewDiscovery(&conf, nil, prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := conf.NewDiscovererMetrics(reg, refreshMetrics)
+	err := metrics.Register()
+	if err != nil {
+		return nil, err
+	}
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	md, err := NewDiscovery(&conf, nil, metrics)
 	if err != nil {
 		return nil, err
 	}

discovery/eureka/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 eureka
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*eurekaMetrics)(nil)
+
+type eurekaMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *eurekaMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *eurekaMetrics) Unregister() {}

discovery/file/file.go

@@ -57,12 +57,17 @@ type SDConfig struct {
 	RefreshInterval model.Duration `yaml:"refresh_interval,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -94,6 +99,9 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 const fileSDFilepathLabel = model.MetaLabelPrefix + "filepath"
 
 // TimestampCollector is a Custom Collector for Timestamps of the files.
+// TODO(ptodev): Now that each file SD has its own TimestampCollector
+// inside discovery/file/metrics.go, we can refactor this collector
+// (or get rid of it) as each TimestampCollector instance will only use one discoverer.
 type TimestampCollector struct {
 	Description *prometheus.Desc
 	discoverers map[*Discovery]struct{}
@@ -169,16 +177,16 @@ type Discovery struct {
 	lastRefresh map[string]int
 	logger      log.Logger
 
-	fileSDReadErrorsCount  prometheus.Counter
-	fileSDScanDuration     prometheus.Summary
-	fileWatcherErrorsCount prometheus.Counter
-	fileSDTimeStamp        *TimestampCollector
-
-	metricRegisterer discovery.MetricRegisterer
+	metrics *fileMetrics
 }
 
 // NewDiscovery returns a new file discovery for the given paths.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	fm, ok := metrics.(*fileMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -188,33 +196,10 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 		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(),
+		metrics:    fm,
 	}
 
-	disc.fileSDTimeStamp.addDiscoverer(disc)
-
-	disc.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
-		disc.fileSDReadErrorsCount,
-		disc.fileSDScanDuration,
-		disc.fileWatcherErrorsCount,
-		disc.fileSDTimeStamp,
-	})
+	fm.init(disc)
 
 	return disc, nil
 }
@@ -253,17 +238,10 @@ 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)
-		d.fileWatcherErrorsCount.Inc()
+		d.metrics.fileWatcherErrorsCount.Inc()
 		return
 	}
 	d.watcher = watcher
@@ -327,7 +305,7 @@ func (d *Discovery) stop() {
 	done := make(chan struct{})
 	defer close(done)
 
-	d.fileSDTimeStamp.removeDiscoverer(d)
+	d.metrics.fileSDTimeStamp.removeDiscoverer(d)
 
 	// Closing the watcher will deadlock unless all events and errors are drained.
 	go func() {
@@ -353,13 +331,13 @@ func (d *Discovery) stop() {
 func (d *Discovery) refresh(ctx context.Context, ch chan<- []*targetgroup.Group) {
 	t0 := time.Now()
 	defer func() {
-		d.fileSDScanDuration.Observe(time.Since(t0).Seconds())
+		d.metrics.fileSDScanDuration.Observe(time.Since(t0).Seconds())
 	}()
 	ref := map[string]int{}
 	for _, p := range d.listFiles() {
 		tgroups, err := d.readFile(p)
 		if err != nil {
-			d.fileSDReadErrorsCount.Inc()
+			d.metrics.fileSDReadErrorsCount.Inc()
 
 			level.Error(d.logger).Log("msg", "Error reading file", "path", p, "err", err)
 			// Prevent deletion down below.

discovery/file/file_test.go

@@ -29,6 +29,7 @@ import (
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -144,19 +145,28 @@ func (t *testRunner) run(files ...string) {
 	ctx, cancel := context.WithCancel(context.Background())
 	t.cancelSD = cancel
 	go func() {
-		d, err := NewDiscovery(
-			&SDConfig{
+		conf := &SDConfig{
 			Files: files,
 			// Setting a high refresh interval to make sure that the tests only
 			// rely on file watches.
 			RefreshInterval: model.Duration(1 * time.Hour),
-			},
+		}
+
+		reg := prometheus.NewRegistry()
+		refreshMetrics := discovery.NewRefreshMetrics(reg)
+		metrics := conf.NewDiscovererMetrics(reg, refreshMetrics)
+		require.NoError(t, metrics.Register())
+
+		d, err := NewDiscovery(
+			conf,
 			nil,
-			prometheus.NewRegistry(),
+			metrics,
 		)
 		require.NoError(t, err)
 
 		d.Run(ctx, t.ch)
+
+		metrics.Unregister()
 	}()
 }
 

discovery/file/metrics.go

@@ -0,0 +1,76 @@
+// Copyright 2015 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 file
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*fileMetrics)(nil)
+
+type fileMetrics struct {
+	fileSDReadErrorsCount  prometheus.Counter
+	fileSDScanDuration     prometheus.Summary
+	fileWatcherErrorsCount prometheus.Counter
+	fileSDTimeStamp        *TimestampCollector
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	fm := &fileMetrics{
+		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(),
+	}
+
+	fm.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		fm.fileSDReadErrorsCount,
+		fm.fileSDScanDuration,
+		fm.fileWatcherErrorsCount,
+		fm.fileSDTimeStamp,
+	})
+
+	return fm
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (fm *fileMetrics) Register() error {
+	return fm.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (fm *fileMetrics) Unregister() {
+	fm.metricRegisterer.UnregisterMetrics()
+}
+
+func (fm *fileMetrics) init(disc *Discovery) {
+	fm.fileSDTimeStamp.addDiscoverer(disc)
+}

discovery/gce/gce.go

@@ -82,12 +82,19 @@ type SDConfig struct {
 	TagSeparator    string         `yaml:"tag_separator,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &gceMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(*c, opts.Logger, opts.Metrics)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
@@ -122,7 +129,12 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*gceMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	d := &Discovery{
 		project:      conf.Project,
 		zone:         conf.Zone,
@@ -147,7 +159,7 @@ func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (
 			Mech:                "gce",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/gce/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 gce
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*gceMetrics)(nil)
+
+type gceMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *gceMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *gceMetrics) Unregister() {}

discovery/hetzner/hetzner.go

@@ -63,12 +63,19 @@ type SDConfig struct {
 	robotEndpoint   string         // For tests only.
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &hetznerMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 type refresher interface {
@@ -128,7 +135,12 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*refresh.Discovery, error) {
+	m, ok := metrics.(*hetznerMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	r, err := newRefresher(conf, logger)
 	if err != nil {
 		return nil, err
@@ -140,7 +152,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "hetzner",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            r.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	), nil
 }

discovery/hetzner/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 hetzner
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*hetznerMetrics)(nil)
+
+type hetznerMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *hetznerMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *hetznerMetrics) Unregister() {}

discovery/http/http.go

@@ -58,12 +58,17 @@ type SDConfig struct {
 	URL              string                  `yaml:"url"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.HTTPClientOptions, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -105,11 +110,16 @@ type Discovery struct {
 	client          *http.Client
 	refreshInterval time.Duration
 	tgLastLength    int
-	failuresCount   prometheus.Counter
+	metrics         *httpMetrics
 }
 
 // NewDiscovery returns a new HTTP discovery for the given config.
-func NewDiscovery(conf *SDConfig, logger log.Logger, clientOpts []config.HTTPClientOption, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, clientOpts []config.HTTPClientOption, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*httpMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -124,11 +134,7 @@ 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.",
-			}),
+		metrics:         m,
 	}
 
 	d.Discovery = refresh.NewDiscovery(
@@ -137,8 +143,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, clientOpts []config.HTTPCli
 			Mech:                "http",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.Refresh,
-			Registry: reg,
-			Metrics:  []prometheus.Collector{d.failuresCount},
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil
@@ -155,7 +160,7 @@ func (d *Discovery) Refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 
 	resp, err := d.client.Do(req.WithContext(ctx))
 	if err != nil {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, err
 	}
 	defer func() {
@@ -164,31 +169,31 @@ func (d *Discovery) Refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 	}()
 
 	if resp.StatusCode != http.StatusOK {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, fmt.Errorf("server returned HTTP status %s", resp.Status)
 	}
 
 	if !matchContentType.MatchString(strings.TrimSpace(resp.Header.Get("Content-Type"))) {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, fmt.Errorf("unsupported content type %q", resp.Header.Get("Content-Type"))
 	}
 
 	b, err := io.ReadAll(resp.Body)
 	if err != nil {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, err
 	}
 
 	var targetGroups []*targetgroup.Group
 
 	if err := json.Unmarshal(b, &targetGroups); err != nil {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, err
 	}
 
 	for i, tg := range targetGroups {
 		if tg == nil {
-			d.failuresCount.Inc()
+			d.metrics.failuresCount.Inc()
 			err = errors.New("nil target group item found")
 			return nil, err
 		}

discovery/http/http_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -41,7 +42,14 @@ func TestHTTPValidRefresh(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	defer refreshMetrics.Unregister()
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -63,7 +71,7 @@ func TestHTTPValidRefresh(t *testing.T) {
 		},
 	}
 	require.Equal(t, expectedTargets, tgs)
-	require.Equal(t, 0.0, getFailureCount(d.failuresCount))
+	require.Equal(t, 0.0, getFailureCount(d.metrics.failuresCount))
 }
 
 func TestHTTPInvalidCode(t *testing.T) {
@@ -79,13 +87,20 @@ func TestHTTPInvalidCode(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	defer refreshMetrics.Unregister()
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, metrics)
 	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(d.failuresCount))
+	require.Equal(t, 1.0, getFailureCount(d.metrics.failuresCount))
 }
 
 func TestHTTPInvalidFormat(t *testing.T) {
@@ -101,13 +116,20 @@ func TestHTTPInvalidFormat(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	defer refreshMetrics.Unregister()
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, metrics)
 	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(d.failuresCount))
+	require.Equal(t, 1.0, getFailureCount(d.metrics.failuresCount))
 }
 
 func getFailureCount(failuresCount prometheus.Counter) float64 {
@@ -412,7 +434,15 @@ func TestSourceDisappeared(t *testing.T) {
 		URL:              ts.URL,
 		RefreshInterval:  model.Duration(1 * time.Second),
 	}
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	defer refreshMetrics.Unregister()
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), nil, metrics)
 	require.NoError(t, err)
 	for _, test := range cases {
 		ctx := context.Background()

discovery/http/metrics.go

@@ -0,0 +1,57 @@
+// Copyright 2015 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 http
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*httpMetrics)(nil)
+
+type httpMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+
+	failuresCount prometheus.Counter
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &httpMetrics{
+		refreshMetrics: rmi,
+		failuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_http_failures_total",
+				Help: "Number of HTTP service discovery refresh failures.",
+			}),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.failuresCount,
+	})
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *httpMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *httpMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/ionos/ionos.go

@@ -15,16 +15,16 @@ package ionos
 
 import (
 	"errors"
+	"fmt"
 	"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/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/refresh"
-
-	"github.com/prometheus/client_golang/prometheus"
 )
 
 const (
@@ -43,7 +43,12 @@ func init() {
 type Discovery struct{}
 
 // NewDiscovery returns a new refresh.Discovery for IONOS Cloud.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*refresh.Discovery, error) {
+	m, ok := metrics.(*ionosMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if conf.ionosEndpoint == "" {
 		conf.ionosEndpoint = "https://api.ionos.com"
 	}
@@ -59,7 +64,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "ionos",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	), nil
 }
@@ -84,6 +89,13 @@ type SDConfig struct {
 	ionosEndpoint string // For tests only.
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &ionosMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the IONOS Cloud service discovery.
 func (c SDConfig) Name() string {
 	return "ionos"
@@ -91,7 +103,7 @@ 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, options.Registerer)
+	return NewDiscovery(&c, options.Logger, options.Metrics)
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.

discovery/ionos/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 ionos
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*ionosMetrics)(nil)
+
+type ionosMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *ionosMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *ionosMetrics) Unregister() {}

discovery/kubernetes/kubernetes.go

@@ -123,12 +123,17 @@ type SDConfig struct {
 	AttachMetadata     AttachMetadataConfig    `yaml:"attach_metadata,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer, c)
+	return New(opts.Logger, opts.Metrics, c)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -265,8 +270,7 @@ type Discovery struct {
 	selectors          roleSelector
 	ownNamespace       string
 	attachMetadata     AttachMetadataConfig
-	eventCount         *prometheus.CounterVec
-	metricRegisterer   discovery.MetricRegisterer
+	metrics            *kubernetesMetrics
 }
 
 func (d *Discovery) getNamespaces() []string {
@@ -285,7 +289,12 @@ func (d *Discovery) getNamespaces() []string {
 }
 
 // New creates a new Kubernetes discovery for the given role.
-func New(l log.Logger, reg prometheus.Registerer, conf *SDConfig) (*Discovery, error) {
+func New(l log.Logger, metrics discovery.DiscovererMetrics, conf *SDConfig) (*Discovery, error) {
+	m, ok := metrics.(*kubernetesMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if l == nil {
 		l = log.NewNopLogger()
 	}
@@ -348,34 +357,7 @@ func New(l log.Logger, reg prometheus.Registerer, conf *SDConfig) (*Discovery, e
 		selectors:          mapSelector(conf.Selectors),
 		ownNamespace:       ownNamespace,
 		attachMetadata:     conf.AttachMetadata,
-		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)
-		}
+		metrics:            m,
 	}
 
 	return d, nil
@@ -415,13 +397,6 @@ const resyncDisabled = 0
 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 {
@@ -513,7 +488,7 @@ 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.metrics.eventCount,
 			)
 			d.discoverers = append(d.discoverers, eps)
 			go eps.endpointSliceInf.Run(ctx.Done())
@@ -573,7 +548,7 @@ 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.metrics.eventCount,
 			)
 			d.discoverers = append(d.discoverers, eps)
 			go eps.endpointsInf.Run(ctx.Done())
@@ -605,7 +580,7 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 				log.With(d.logger, "role", "pod"),
 				d.newPodsByNodeInformer(plw),
 				nodeInformer,
-				d.eventCount,
+				d.metrics.eventCount,
 			)
 			d.discoverers = append(d.discoverers, pod)
 			go pod.podInf.Run(ctx.Done())
@@ -628,7 +603,7 @@ 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.metrics.eventCount,
 			)
 			d.discoverers = append(d.discoverers, svc)
 			go svc.informer.Run(ctx.Done())
@@ -686,14 +661,14 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 			ingress := NewIngress(
 				log.With(d.logger, "role", "ingress"),
 				informer,
-				d.eventCount,
+				d.metrics.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, d.eventCount)
+		node := NewNode(log.With(d.logger, "role", "node"), nodeInformer, d.metrics.eventCount)
 		d.discoverers = append(d.discoverers, node)
 		go node.informer.Run(ctx.Done())
 	default:

discovery/kubernetes/kubernetes_test.go

@@ -51,24 +51,29 @@ func makeDiscoveryWithVersion(role Role, nsDiscovery NamespaceDiscovery, k8sVer
 	fakeDiscovery, _ := clientset.Discovery().(*fakediscovery.FakeDiscovery)
 	fakeDiscovery.FakedServerVersion = &version.Info{GitVersion: k8sVer}
 
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := newDiscovererMetrics(reg, refreshMetrics)
+	err := metrics.Register()
+	if err != nil {
+		panic(err)
+	}
+	// TODO(ptodev): Unregister the metrics at the end of the test.
+
+	kubeMetrics, ok := metrics.(*kubernetesMetrics)
+	if !ok {
+		panic("invalid discovery metrics type")
+	}
+
 	d := &Discovery{
 		client:             clientset,
 		logger:             log.NewNopLogger(),
 		role:               role,
 		namespaceDiscovery: &nsDiscovery,
 		ownNamespace:       "own-ns",
-		eventCount: prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: discovery.KubernetesMetricsNamespace,
-				Name:      "events_total",
-				Help:      "The number of Kubernetes events handled.",
-			},
-			[]string{"role", "event"},
-		),
+		metrics:            kubeMetrics,
 	}
 
-	d.metricRegisterer = discovery.NewMetricRegisterer(prometheus.NewRegistry(), []prometheus.Collector{d.eventCount})
-
 	return d, clientset
 }
 

discovery/kubernetes/metrics.go

@@ -0,0 +1,75 @@
+// Copyright 2015 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 kubernetes
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*kubernetesMetrics)(nil)
+
+type kubernetesMetrics struct {
+	eventCount *prometheus.CounterVec
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &kubernetesMetrics{
+		eventCount: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: discovery.KubernetesMetricsNamespace,
+				Name:      "events_total",
+				Help:      "The number of Kubernetes events handled.",
+			},
+			[]string{"role", "event"},
+		),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.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,
+		} {
+			m.eventCount.WithLabelValues(role, evt)
+		}
+	}
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *kubernetesMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *kubernetesMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/legacymanager/manager.go

@@ -42,7 +42,7 @@ type provider struct {
 }
 
 // NewManager is the Discovery Manager constructor.
-func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Registerer, options ...func(*Manager)) *Manager {
+func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Registerer, sdMetrics map[string]discovery.DiscovererMetrics, options ...func(*Manager)) *Manager {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -55,6 +55,7 @@ func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Re
 		updatert:       5 * time.Second,
 		triggerSend:    make(chan struct{}, 1),
 		registerer:     registerer,
+		sdMetrics:      sdMetrics,
 	}
 	for _, option := range options {
 		option(mgr)
@@ -62,7 +63,7 @@ func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Re
 
 	// 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 {
+	if metrics, err := discovery.NewManagerMetrics(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)
@@ -109,6 +110,7 @@ type Manager struct {
 	registerer prometheus.Registerer
 
 	metrics   *discovery.Metrics
+	sdMetrics map[string]discovery.DiscovererMetrics
 }
 
 // Run starts the background processing.
@@ -284,7 +286,7 @@ 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),
-			Registerer: m.registerer,
+			Metrics: m.sdMetrics[typ],
 		})
 		if err != nil {
 			level.Error(m.logger).Log("msg", "Cannot create service discovery", "err", err, "type", typ, "config", setName)

discovery/legacymanager/manager_test.go

@@ -36,6 +36,13 @@ func TestMain(m *testing.M) {
 	testutil.TolerantVerifyLeak(m)
 }
 
+func newTestMetrics(t *testing.T, reg prometheus.Registerer) (*discovery.RefreshMetricsManager, map[string]discovery.DiscovererMetrics) {
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	sdMetrics, err := discovery.RegisterSDMetrics(reg, refreshMetrics)
+	require.NoError(t, err)
+	return &refreshMetrics, sdMetrics
+}
+
 // TestTargetUpdatesOrder checks that the target updates are received in the expected order.
 func TestTargetUpdatesOrder(t *testing.T) {
 	// The order by which the updates are send is determined by the interval passed to the mock discovery adapter
@@ -665,7 +672,10 @@ func TestTargetUpdatesOrder(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+			reg := prometheus.NewRegistry()
+			_, sdMetrics := newTestMetrics(t, reg)
+
+			discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 			require.NotNil(t, discoveryManager)
 			discoveryManager.updatert = 100 * time.Millisecond
 
@@ -748,7 +758,11 @@ 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(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := newTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -777,7 +791,11 @@ func TestTargetSetRecreatesTargetGroupsEveryRun(t *testing.T) {
 func TestDiscovererConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := newTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -802,7 +820,11 @@ func TestDiscovererConfigs(t *testing.T) {
 func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := newTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -842,7 +864,11 @@ func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 func TestIdenticalConfigurationsAreCoalesced(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, nil, prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := newTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, nil, reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -874,7 +900,11 @@ func TestApplyConfigDoesNotModifyStaticTargets(t *testing.T) {
 	}
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := newTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -897,10 +927,19 @@ func (e errorConfig) NewDiscoverer(discovery.DiscovererOptions) (discovery.Disco
 	return nil, e.err
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (errorConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &discovery.NoopDiscovererMetrics{}
+}
+
 func TestGaugeFailedConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := newTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -1057,7 +1096,10 @@ func TestCoordinationWithReceiver(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			mgr := NewManager(ctx, nil, prometheus.NewRegistry())
+			reg := prometheus.NewRegistry()
+			_, sdMetrics := newTestMetrics(t, reg)
+
+			mgr := NewManager(ctx, nil, reg, sdMetrics)
 			require.NotNil(t, mgr)
 			mgr.updatert = updateDelay
 			go mgr.Run()

discovery/linode/linode.go

@@ -87,12 +87,17 @@ type SDConfig struct {
 	TagSeparator    string         `yaml:"tag_separator,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -122,22 +127,23 @@ type Discovery struct {
 	pollCount            int
 	lastResults          []*targetgroup.Group
 	eventPollingEnabled  bool
-	failuresCount        prometheus.Counter
+	metrics              *linodeMetrics
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*linodeMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	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.",
-			}),
+		metrics:              m,
 	}
 
 	rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "linode_sd")
@@ -160,8 +166,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "linode",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
-			Metrics:  []prometheus.Collector{d.failuresCount},
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil
@@ -223,14 +228,14 @@ 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 {
-		d.failuresCount.Inc()
+		d.metrics.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 {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, err
 	}
 

discovery/linode/linode_test.go

@@ -24,6 +24,8 @@ import (
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 type LinodeSDTestSuite struct {
@@ -53,7 +55,15 @@ func TestLinodeSDRefresh(t *testing.T) {
 		Credentials: tokenID,
 		Type:        "Bearer",
 	}
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 	endpoint, err := url.Parse(sdmock.Mock.Endpoint())
 	require.NoError(t, err)

discovery/linode/metrics.go

@@ -0,0 +1,57 @@
+// Copyright 2015 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 linode
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*linodeMetrics)(nil)
+
+type linodeMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+
+	failuresCount prometheus.Counter
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &linodeMetrics{
+		refreshMetrics: rmi,
+		failuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_linode_failures_total",
+				Help: "Number of Linode service discovery refresh failures.",
+			}),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.failuresCount,
+	})
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *linodeMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *linodeMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/manager.go

@@ -64,8 +64,24 @@ func (p *Provider) Config() interface{} {
 	return p.config
 }
 
+// Registers the metrics needed for SD mechanisms.
+// Does not register the metrics for the Discovery Manager.
+// TODO(ptodev): Add ability to unregister the metrics?
+func CreateAndRegisterSDMetrics(reg prometheus.Registerer) (map[string]DiscovererMetrics, error) {
+	// Some SD mechanisms use the "refresh" package, which has its own metrics.
+	refreshSdMetrics := NewRefreshMetrics(reg)
+
+	// Register the metrics specific for each SD mechanism, and the ones for the refresh package.
+	sdMetrics, err := RegisterSDMetrics(reg, refreshSdMetrics)
+	if err != nil {
+		return nil, fmt.Errorf("failed to register service discovery metrics: %w", err)
+	}
+
+	return sdMetrics, nil
+}
+
 // NewManager is the Discovery Manager constructor.
-func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Registerer, options ...func(*Manager)) *Manager {
+func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Registerer, sdMetrics map[string]DiscovererMetrics, options ...func(*Manager)) *Manager {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -77,6 +93,7 @@ func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Re
 		updatert:    5 * time.Second,
 		triggerSend: make(chan struct{}, 1),
 		registerer:  registerer,
+		sdMetrics:   sdMetrics,
 	}
 	for _, option := range options {
 		option(mgr)
@@ -84,7 +101,7 @@ func NewManager(ctx context.Context, logger log.Logger, registerer prometheus.Re
 
 	// 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 {
+	if metrics, err := NewManagerMetrics(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)
@@ -144,6 +161,7 @@ type Manager struct {
 	registerer prometheus.Registerer
 
 	metrics   *Metrics
+	sdMetrics map[string]DiscovererMetrics
 }
 
 // Providers returns the currently configured SD providers.
@@ -402,7 +420,7 @@ 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,
+			Metrics:           m.sdMetrics[typ],
 		})
 		if err != nil {
 			level.Error(m.logger).Log("msg", "Cannot create service discovery", "err", err, "type", typ, "config", setName)

discovery/manager_test.go

@@ -36,6 +36,13 @@ func TestMain(m *testing.M) {
 	testutil.TolerantVerifyLeak(m)
 }
 
+func NewTestMetrics(t *testing.T, reg prometheus.Registerer) (*RefreshMetricsManager, map[string]DiscovererMetrics) {
+	refreshMetrics := NewRefreshMetrics(reg)
+	sdMetrics, err := RegisterSDMetrics(reg, refreshMetrics)
+	require.NoError(t, err)
+	return &refreshMetrics, sdMetrics
+}
+
 // TestTargetUpdatesOrder checks that the target updates are received in the expected order.
 func TestTargetUpdatesOrder(t *testing.T) {
 	// The order by which the updates are send is determined by the interval passed to the mock discovery adapter
@@ -665,7 +672,10 @@ func TestTargetUpdatesOrder(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+			reg := prometheus.NewRegistry()
+			_, sdMetrics := NewTestMetrics(t, reg)
+
+			discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 			require.NotNil(t, discoveryManager)
 			discoveryManager.updatert = 100 * time.Millisecond
 
@@ -780,7 +790,11 @@ 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(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -813,7 +827,11 @@ func TestTargetSetTargetGroupsPresentOnConfigReload(t *testing.T) {
 func TestTargetSetTargetGroupsPresentOnConfigRename(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -849,7 +867,11 @@ func TestTargetSetTargetGroupsPresentOnConfigRename(t *testing.T) {
 func TestTargetSetTargetGroupsPresentOnConfigDuplicateAndDeleteOriginal(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -888,7 +910,11 @@ func TestTargetSetTargetGroupsPresentOnConfigDuplicateAndDeleteOriginal(t *testi
 func TestTargetSetTargetGroupsPresentOnConfigChange(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -950,7 +976,11 @@ func TestTargetSetTargetGroupsPresentOnConfigChange(t *testing.T) {
 func TestTargetSetRecreatesTargetGroupsOnConfigChange(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -990,7 +1020,11 @@ func TestTargetSetRecreatesTargetGroupsOnConfigChange(t *testing.T) {
 func TestDiscovererConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -1023,7 +1057,11 @@ func TestDiscovererConfigs(t *testing.T) {
 func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -1071,7 +1109,11 @@ func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 func TestIdenticalConfigurationsAreCoalesced(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, nil, prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, nil, reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -1108,7 +1150,11 @@ func TestApplyConfigDoesNotModifyStaticTargets(t *testing.T) {
 	}
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -1129,11 +1175,21 @@ type errorConfig struct{ err error }
 func (e errorConfig) Name() string                                        { return "error" }
 func (e errorConfig) NewDiscoverer(DiscovererOptions) (Discoverer, error) { return nil, e.err }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (errorConfig) NewDiscovererMetrics(prometheus.Registerer, RefreshMetricsInstantiator) DiscovererMetrics {
+	return &NoopDiscovererMetrics{}
+}
+
 type lockStaticConfig struct {
 	mu     *sync.Mutex
 	config StaticConfig
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (lockStaticConfig) NewDiscovererMetrics(prometheus.Registerer, RefreshMetricsInstantiator) DiscovererMetrics {
+	return &NoopDiscovererMetrics{}
+}
+
 func (s lockStaticConfig) Name() string { return "lockstatic" }
 func (s lockStaticConfig) NewDiscoverer(DiscovererOptions) (Discoverer, error) {
 	return (lockStaticDiscoverer)(s), nil
@@ -1155,7 +1211,11 @@ 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(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -1312,7 +1372,10 @@ func TestCoordinationWithReceiver(t *testing.T) {
 			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
 
-			mgr := NewManager(ctx, nil, prometheus.NewRegistry())
+			reg := prometheus.NewRegistry()
+			_, sdMetrics := NewTestMetrics(t, reg)
+
+			mgr := NewManager(ctx, nil, reg, sdMetrics)
 			require.NotNil(t, mgr)
 			mgr.updatert = updateDelay
 			go mgr.Run()
@@ -1408,7 +1471,11 @@ func (o onceProvider) Run(_ context.Context, ch chan<- []*targetgroup.Group) {
 func TestTargetSetTargetGroupsUpdateDuringApplyConfig(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	discoveryManager := NewManager(ctx, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	_, sdMetrics := NewTestMetrics(t, reg)
+
+	discoveryManager := NewManager(ctx, log.NewNopLogger(), reg, sdMetrics)
 	require.NotNil(t, discoveryManager)
 	discoveryManager.updatert = 100 * time.Millisecond
 	go discoveryManager.Run()
@@ -1470,6 +1537,11 @@ func newTestDiscoverer() *testDiscoverer {
 	}
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*testDiscoverer) NewDiscovererMetrics(prometheus.Registerer, RefreshMetricsInstantiator) DiscovererMetrics {
+	return &NoopDiscovererMetrics{}
+}
+
 // Name implements Config.
 func (t *testDiscoverer) Name() string {
 	return "test"

discovery/marathon/marathon.go

@@ -79,12 +79,19 @@ type SDConfig struct {
 	HTTPClientConfig config.HTTPClientConfig `yaml:",inline"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &marathonMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(*c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -133,7 +140,12 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Marathon Discovery.
-func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*marathonMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "marathon_sd")
 	if err != nil {
 		return nil, err
@@ -160,7 +172,7 @@ func NewDiscovery(conf SDConfig, logger log.Logger, reg prometheus.Registerer) (
 			Mech:                "marathon",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/marathon/marathon_test.go

@@ -23,7 +23,9 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
+	"github.com/stretchr/testify/require"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -37,7 +39,19 @@ func testConfig() SDConfig {
 }
 
 func testUpdateServices(client appListClient) ([]*targetgroup.Group, error) {
-	md, err := NewDiscovery(testConfig(), nil, prometheus.NewRegistry())
+	cfg := testConfig()
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	err := metrics.Register()
+	if err != nil {
+		return nil, err
+	}
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	md, err := NewDiscovery(cfg, nil, metrics)
 	if err != nil {
 		return nil, err
 	}
@@ -130,7 +144,15 @@ func TestMarathonSDSendGroup(t *testing.T) {
 }
 
 func TestMarathonSDRemoveApp(t *testing.T) {
-	md, err := NewDiscovery(testConfig(), nil, prometheus.NewRegistry())
+	cfg := testConfig()
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	md, err := NewDiscovery(cfg, nil, metrics)
 	if err != nil {
 		t.Fatalf("%s", err)
 	}

discovery/marathon/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 marathon
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*marathonMetrics)(nil)
+
+type marathonMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *marathonMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *marathonMetrics) Unregister() {}

discovery/metrics.go

@@ -38,7 +38,7 @@ type Metrics struct {
 	SentUpdates       prometheus.Counter
 }
 
-func NewMetrics(registerer prometheus.Registerer, sdManagerName string) (*Metrics, error) {
+func NewManagerMetrics(registerer prometheus.Registerer, sdManagerName string) (*Metrics, error) {
 	m := &Metrics{}
 
 	m.FailedConfigs = prometheus.NewGauge(

discovery/metrics_refresh.go

@@ -0,0 +1,75 @@
+// Copyright 2015 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 (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Metric vectors for the "refresh" package.
+// We define them here in the "discovery" package in order to avoid a cyclic dependency between
+// "discovery" and "refresh".
+type RefreshMetricsVecs struct {
+	failuresVec *prometheus.CounterVec
+	durationVec *prometheus.SummaryVec
+
+	metricRegisterer MetricRegisterer
+}
+
+var _ RefreshMetricsManager = (*RefreshMetricsVecs)(nil)
+
+func NewRefreshMetrics(reg prometheus.Registerer) RefreshMetricsManager {
+	m := &RefreshMetricsVecs{
+		failuresVec: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_refresh_failures_total",
+				Help: "Number of refresh failures for the given SD mechanism.",
+			},
+			[]string{"mechanism"}),
+		durationVec: 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"}),
+	}
+
+	// The reason we register metric vectors instead of metrics is so that
+	// the metrics are not visible until they are recorded.
+	m.metricRegisterer = NewMetricRegisterer(reg, []prometheus.Collector{
+		m.failuresVec,
+		m.durationVec,
+	})
+
+	return m
+}
+
+// Instantiate returns metrics out of metric vectors.
+func (m *RefreshMetricsVecs) Instantiate(mech string) *RefreshMetrics {
+	return &RefreshMetrics{
+		Failures: m.failuresVec.WithLabelValues(mech),
+		Duration: m.durationVec.WithLabelValues(mech),
+	}
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *RefreshMetricsVecs) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *RefreshMetricsVecs) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/moby/docker.go

@@ -76,12 +76,19 @@ type DockerSDConfig struct {
 	RefreshInterval model.Duration `yaml:"refresh_interval"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*DockerSDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &dockerMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDockerDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -115,8 +122,11 @@ type DockerDiscovery struct {
 }
 
 // NewDockerDiscovery returns a new DockerDiscovery which periodically refreshes its targets.
-func NewDockerDiscovery(conf *DockerSDConfig, logger log.Logger, reg prometheus.Registerer) (*DockerDiscovery, error) {
-	var err error
+func NewDockerDiscovery(conf *DockerSDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*DockerDiscovery, error) {
+	m, ok := metrics.(*dockerMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
 
 	d := &DockerDiscovery{
 		port:               conf.Port,
@@ -171,7 +181,7 @@ func NewDockerDiscovery(conf *DockerSDConfig, logger log.Logger, reg prometheus.
 			Mech:                "docker",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/moby/docker_test.go

@@ -23,6 +23,8 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 func TestDockerSDRefresh(t *testing.T) {
@@ -38,7 +40,14 @@ host: %s
 	var cfg DockerSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDockerDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDockerDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()

discovery/moby/dockerswarm.go

@@ -70,12 +70,19 @@ type Filter struct {
 	Values []string `yaml:"values"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*DockerSwarmSDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &dockerswarmMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -118,8 +125,11 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *DockerSwarmSDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
-	var err error
+func NewDiscovery(conf *DockerSwarmSDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*dockerswarmMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
 
 	d := &Discovery{
 		port: conf.Port,
@@ -174,7 +184,7 @@ func NewDiscovery(conf *DockerSwarmSDConfig, logger log.Logger, reg prometheus.R
 			Mech:                "dockerswarm",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/moby/metrics_docker.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 moby
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*dockerMetrics)(nil)
+
+type dockerMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *dockerMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *dockerMetrics) Unregister() {}

discovery/moby/metrics_dockerswarm.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 moby
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*dockerswarmMetrics)(nil)
+
+type dockerswarmMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *dockerswarmMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *dockerswarmMetrics) Unregister() {}

discovery/moby/nodes_test.go

@@ -23,6 +23,8 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 func TestDockerSwarmNodesSDRefresh(t *testing.T) {
@@ -39,7 +41,14 @@ host: %s
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()

discovery/moby/services_test.go

@@ -23,6 +23,8 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 func TestDockerSwarmSDServicesRefresh(t *testing.T) {
@@ -39,7 +41,14 @@ host: %s
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -333,7 +342,14 @@ filters:
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()

discovery/moby/tasks_test.go

@@ -23,6 +23,8 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 func TestDockerSwarmTasksSDRefresh(t *testing.T) {
@@ -39,7 +41,14 @@ host: %s
 	var cfg DockerSwarmSDConfig
 	require.NoError(t, yaml.Unmarshal([]byte(cfgString), &cfg))
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()

discovery/nomad/metrics.go

@@ -0,0 +1,57 @@
+// Copyright 2015 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 nomad
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*nomadMetrics)(nil)
+
+type nomadMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+
+	failuresCount prometheus.Counter
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &nomadMetrics{
+		refreshMetrics: rmi,
+		failuresCount: prometheus.NewCounter(
+			prometheus.CounterOpts{
+				Name: "prometheus_sd_nomad_failures_total",
+				Help: "Number of nomad service discovery refresh failures.",
+			}),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.failuresCount,
+	})
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *nomadMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *nomadMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/nomad/nomad.go

@@ -74,12 +74,17 @@ type SDConfig struct {
 	TagSeparator     string                  `yaml:"tag_separator,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -112,11 +117,16 @@ type Discovery struct {
 	region          string
 	server          string
 	tagSeparator    string
-	failuresCount   prometheus.Counter
+	metrics         *nomadMetrics
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*nomadMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	d := &Discovery{
 		allowStale:      conf.AllowStale,
 		namespace:       conf.Namespace,
@@ -124,11 +134,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 		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.",
-			}),
+		metrics:         m,
 	}
 
 	HTTPClient, err := config.NewClientFromConfig(conf.HTTPClientConfig, "nomad_sd")
@@ -155,8 +161,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "nomad",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
-			Metrics:  []prometheus.Collector{d.failuresCount},
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil
@@ -168,7 +173,7 @@ func (d *Discovery) refresh(context.Context) ([]*targetgroup.Group, error) {
 	}
 	stubs, _, err := d.client.Services().List(opts)
 	if err != nil {
-		d.failuresCount.Inc()
+		d.metrics.failuresCount.Inc()
 		return nil, err
 	}
 
@@ -180,7 +185,7 @@ 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 {
-				d.failuresCount.Inc()
+				d.metrics.failuresCount.Inc()
 				return nil, fmt.Errorf("failed to fetch services: %w", err)
 			}
 

discovery/nomad/nomad_test.go

@@ -25,6 +25,8 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 type NomadSDTestSuite struct {
@@ -128,8 +130,16 @@ func TestConfiguredService(t *testing.T) {
 	conf := &SDConfig{
 		Server: "http://localhost:4646",
 	}
-	_, err := NewDiscovery(conf, nil, prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := conf.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	_, err := NewDiscovery(conf, nil, metrics)
 	require.NoError(t, err)
+
+	metrics.Unregister()
 }
 
 func TestNomadSDRefresh(t *testing.T) {
@@ -142,7 +152,15 @@ func TestNomadSDRefresh(t *testing.T) {
 
 	cfg := DefaultSDConfig
 	cfg.Server = endpoint.String()
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	tgs, err := d.refresh(context.Background())

discovery/openstack/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 openstack
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+type openstackMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+var _ discovery.DiscovererMetrics = (*openstackMetrics)(nil)
+
+// Register implements discovery.DiscovererMetrics.
+func (m *openstackMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *openstackMetrics) Unregister() {}

discovery/openstack/openstack.go

@@ -66,12 +66,19 @@ type SDConfig struct {
 	Availability                string           `yaml:"availability,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &openstackMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -135,7 +142,12 @@ type refresher interface {
 }
 
 // NewDiscovery returns a new OpenStack Discoverer which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, l log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, l log.Logger, metrics discovery.DiscovererMetrics) (*refresh.Discovery, error) {
+	m, ok := metrics.(*openstackMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	r, err := newRefresher(conf, l)
 	if err != nil {
 		return nil, err
@@ -146,7 +158,7 @@ func NewDiscovery(conf *SDConfig, l log.Logger, reg prometheus.Registerer) (*ref
 			Mech:                "openstack",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            r.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	), nil
 }

discovery/ovhcloud/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 ovhcloud
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*ovhcloudMetrics)(nil)
+
+type ovhcloudMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *ovhcloudMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *ovhcloudMetrics) Unregister() {}

discovery/ovhcloud/ovhcloud.go

@@ -53,6 +53,13 @@ type SDConfig struct {
 	Service           string         `yaml:"service"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &ovhcloudMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name implements the Discoverer interface.
 func (c SDConfig) Name() string {
 	return "ovhcloud"
@@ -94,7 +101,7 @@ 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, options.Registerer)
+	return NewDiscovery(c, options.Logger, options.Metrics)
 }
 
 func init() {
@@ -141,7 +148,12 @@ 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, reg prometheus.Registerer) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*refresh.Discovery, error) {
+	m, ok := metrics.(*ovhcloudMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	r, err := newRefresher(conf, logger)
 	if err != nil {
 		return nil, err
@@ -153,7 +165,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "ovhcloud",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            r.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	), nil
 }

discovery/ovhcloud/ovhcloud_test.go

@@ -122,9 +122,17 @@ func TestParseIPs(t *testing.T) {
 func TestDiscoverer(t *testing.T) {
 	conf, _ := getMockConf("vps")
 	logger := testutil.NewLogger(t)
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := conf.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
 	_, err := conf.NewDiscoverer(discovery.DiscovererOptions{
 		Logger:  logger,
-		Registerer: prometheus.NewRegistry(),
+		Metrics: metrics,
 	})
 
 	require.NoError(t, err)

discovery/puppetdb/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 puppetdb
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*puppetdbMetrics)(nil)
+
+type puppetdbMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *puppetdbMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *puppetdbMetrics) Unregister() {}

discovery/puppetdb/puppetdb.go

@@ -79,12 +79,19 @@ type SDConfig struct {
 	Port              int                     `yaml:"port"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &puppetdbMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -131,7 +138,12 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new PuppetDB discovery for the given config.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*puppetdbMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -162,7 +174,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "http",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/puppetdb/puppetdb_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -63,9 +64,17 @@ func TestPuppetSlashInURL(t *testing.T) {
 			Port:             80,
 			RefreshInterval:  model.Duration(30 * time.Second),
 		}
-		d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+
+		reg := prometheus.NewRegistry()
+		refreshMetrics := discovery.NewRefreshMetrics(reg)
+		metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+		require.NoError(t, metrics.Register())
+
+		d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 		require.NoError(t, err)
 		require.Equal(t, apiURL, d.url)
+
+		metrics.Unregister()
 	}
 }
 
@@ -80,7 +89,12 @@ func TestPuppetDBRefresh(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -107,6 +121,8 @@ func TestPuppetDBRefresh(t *testing.T) {
 		},
 	}
 	require.Equal(t, expectedTargets, tgs)
+
+	metrics.Unregister()
 }
 
 func TestPuppetDBRefreshWithParameters(t *testing.T) {
@@ -121,7 +137,12 @@ func TestPuppetDBRefreshWithParameters(t *testing.T) {
 		RefreshInterval:   model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -158,6 +179,8 @@ func TestPuppetDBRefreshWithParameters(t *testing.T) {
 		},
 	}
 	require.Equal(t, expectedTargets, tgs)
+
+	metrics.Unregister()
 }
 
 func TestPuppetDBInvalidCode(t *testing.T) {
@@ -173,12 +196,19 @@ func TestPuppetDBInvalidCode(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	_, err = d.refresh(ctx)
 	require.EqualError(t, err, "server returned HTTP status 400 Bad Request")
+
+	metrics.Unregister()
 }
 
 func TestPuppetDBInvalidFormat(t *testing.T) {
@@ -194,10 +224,17 @@ func TestPuppetDBInvalidFormat(t *testing.T) {
 		RefreshInterval:  model.Duration(30 * time.Second),
 	}
 
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 
 	ctx := context.Background()
 	_, err = d.refresh(ctx)
 	require.EqualError(t, err, "unsupported content type text/plain; charset=utf-8")
+
+	metrics.Unregister()
 }

discovery/refresh/refresh.go

@@ -20,7 +20,6 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
-	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
@@ -31,8 +30,7 @@ type Options struct {
 	Mech                string
 	Interval            time.Duration
 	RefreshF            func(ctx context.Context) ([]*targetgroup.Group, error)
-	Registry prometheus.Registerer
-	Metrics  []prometheus.Collector
+	MetricsInstantiator discovery.RefreshMetricsInstantiator
 }
 
 // Discovery implements the Discoverer interface.
@@ -40,15 +38,13 @@ type Discovery struct {
 	logger   log.Logger
 	interval time.Duration
 	refreshf func(ctx context.Context) ([]*targetgroup.Group, error)
-
-	failures prometheus.Counter
-	duration prometheus.Summary
-
-	metricRegisterer discovery.MetricRegisterer
+	metrics  *discovery.RefreshMetrics
 }
 
 // NewDiscovery returns a Discoverer function that calls a refresh() function at every interval.
 func NewDiscovery(opts Options) *Discovery {
+	m := opts.MetricsInstantiator.Instantiate(opts.Mech)
+
 	var logger log.Logger
 	if opts.Logger == nil {
 		logger = log.NewNopLogger()
@@ -60,44 +56,14 @@ func NewDiscovery(opts Options) *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:  m,
 	}
 
-	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 {
@@ -140,12 +106,12 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 	now := time.Now()
 	defer func() {
-		d.duration.Observe(time.Since(now).Seconds())
+		d.metrics.Duration.Observe(time.Since(now).Seconds())
 	}()
 
 	tgs, err := d.refreshf(ctx)
 	if err != nil {
-		d.failures.Inc()
+		d.metrics.Failures.Inc()
 	}
 	return tgs, err
 }

discovery/refresh/refresh_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -66,13 +67,18 @@ func TestRefresh(t *testing.T) {
 		return nil, fmt.Errorf("some error")
 	}
 	interval := time.Millisecond
+
+	metrics := discovery.NewRefreshMetrics(prometheus.NewRegistry())
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+
 	d := NewDiscovery(
 		Options{
 			Logger:              nil,
 			Mech:                "test",
 			Interval:            interval,
 			RefreshF:            refresh,
-			Registry: prometheus.NewRegistry(),
+			MetricsInstantiator: metrics,
 		},
 	)
 

discovery/registry.go

@@ -24,6 +24,8 @@ import (
 
 	"gopkg.in/yaml.v2"
 
+	"github.com/prometheus/client_golang/prometheus"
+
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -258,3 +260,24 @@ func replaceYAMLTypeError(err error, oldTyp, newTyp reflect.Type) error {
 	}
 	return err
 }
+
+// RegisterSDMetrics registers the metrics used by service discovery mechanisms.
+// RegisterSDMetrics should be called only once during the lifetime of the Prometheus process.
+// There is no need for the Prometheus process to unregister the metrics.
+func RegisterSDMetrics(registerer prometheus.Registerer, rmm RefreshMetricsManager) (map[string]DiscovererMetrics, error) {
+	err := rmm.Register()
+	if err != nil {
+		return nil, fmt.Errorf("failed to create service discovery refresh metrics")
+	}
+
+	metrics := make(map[string]DiscovererMetrics)
+	for _, conf := range configNames {
+		currentSdMetrics := conf.NewDiscovererMetrics(registerer, rmm)
+		err = currentSdMetrics.Register()
+		if err != nil {
+			return nil, fmt.Errorf("failed to create service discovery metrics")
+		}
+		metrics[conf.Name()] = currentSdMetrics
+	}
+	return metrics, nil
+}

discovery/scaleway/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 scaleway
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*scalewayMetrics)(nil)
+
+type scalewayMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *scalewayMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *scalewayMetrics) Unregister() {}

discovery/scaleway/scaleway.go

@@ -104,6 +104,13 @@ type SDConfig struct {
 	Role role `yaml:"role"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &scalewayMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 func (c SDConfig) Name() string {
 	return "scaleway"
 }
@@ -161,7 +168,7 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 }
 
 func (c SDConfig) NewDiscoverer(options discovery.DiscovererOptions) (discovery.Discoverer, error) {
-	return NewDiscovery(&c, options.Logger, options.Registerer)
+	return NewDiscovery(&c, options.Logger, options.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -178,7 +185,12 @@ func init() {
 // the Discoverer interface.
 type Discovery struct{}
 
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*refresh.Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*refresh.Discovery, error) {
+	m, ok := metrics.(*scalewayMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	r, err := newRefresher(conf)
 	if err != nil {
 		return nil, err
@@ -190,7 +202,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "scaleway",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            r.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	), nil
 }

discovery/triton/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 triton
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*tritonMetrics)(nil)
+
+type tritonMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *tritonMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *tritonMetrics) Unregister() {}

discovery/triton/triton.go

@@ -70,12 +70,19 @@ type SDConfig struct {
 	Version         int              `yaml:"version"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &tritonMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return New(opts.Logger, c, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -139,7 +146,12 @@ type Discovery struct {
 }
 
 // New returns a new Discovery which periodically refreshes its targets.
-func New(logger log.Logger, conf *SDConfig, reg prometheus.Registerer) (*Discovery, error) {
+func New(logger log.Logger, conf *SDConfig, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*tritonMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	tls, err := config.NewTLSConfig(&conf.TLSConfig)
 	if err != nil {
 		return nil, err
@@ -165,7 +177,7 @@ func New(logger log.Logger, conf *SDConfig, reg prometheus.Registerer) (*Discove
 			Mech:                "triton",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/triton/triton_test.go

@@ -28,6 +28,8 @@ import (
 	"github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 var (
@@ -79,12 +81,26 @@ var (
 	}
 )
 
-func newTritonDiscovery(c SDConfig) (*Discovery, error) {
-	return New(nil, &c, prometheus.NewRegistry())
+func newTritonDiscovery(c SDConfig) (*Discovery, discovery.DiscovererMetrics, error) {
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	// TODO(ptodev): Add the ability to unregister refresh metrics.
+	metrics := c.NewDiscovererMetrics(reg, refreshMetrics)
+	err := metrics.Register()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	d, err := New(nil, &c, metrics)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return d, metrics, nil
 }
 
 func TestTritonSDNew(t *testing.T) {
-	td, err := newTritonDiscovery(conf)
+	td, m, err := newTritonDiscovery(conf)
 	require.NoError(t, err)
 	require.NotNil(t, td)
 	require.NotNil(t, td.client)
@@ -94,16 +110,17 @@ func TestTritonSDNew(t *testing.T) {
 	require.Equal(t, conf.DNSSuffix, td.sdConfig.DNSSuffix)
 	require.Equal(t, conf.Endpoint, td.sdConfig.Endpoint)
 	require.Equal(t, conf.Port, td.sdConfig.Port)
+	m.Unregister()
 }
 
 func TestTritonSDNewBadConfig(t *testing.T) {
-	td, err := newTritonDiscovery(badconf)
+	td, _, err := newTritonDiscovery(badconf)
 	require.Error(t, err)
 	require.Nil(t, td)
 }
 
 func TestTritonSDNewGroupsConfig(t *testing.T) {
-	td, err := newTritonDiscovery(groupsconf)
+	td, m, err := newTritonDiscovery(groupsconf)
 	require.NoError(t, err)
 	require.NotNil(t, td)
 	require.NotNil(t, td.client)
@@ -114,10 +131,11 @@ func TestTritonSDNewGroupsConfig(t *testing.T) {
 	require.Equal(t, groupsconf.Endpoint, td.sdConfig.Endpoint)
 	require.Equal(t, groupsconf.Groups, td.sdConfig.Groups)
 	require.Equal(t, groupsconf.Port, td.sdConfig.Port)
+	m.Unregister()
 }
 
 func TestTritonSDNewCNConfig(t *testing.T) {
-	td, err := newTritonDiscovery(cnconf)
+	td, m, err := newTritonDiscovery(cnconf)
 	require.NoError(t, err)
 	require.NotNil(t, td)
 	require.NotNil(t, td.client)
@@ -128,6 +146,7 @@ func TestTritonSDNewCNConfig(t *testing.T) {
 	require.Equal(t, cnconf.DNSSuffix, td.sdConfig.DNSSuffix)
 	require.Equal(t, cnconf.Endpoint, td.sdConfig.Endpoint)
 	require.Equal(t, cnconf.Port, td.sdConfig.Port)
+	m.Unregister()
 }
 
 func TestTritonSDRefreshNoTargets(t *testing.T) {
@@ -160,21 +179,23 @@ func TestTritonSDRefreshMultipleTargets(t *testing.T) {
 }
 
 func TestTritonSDRefreshNoServer(t *testing.T) {
-	td, _ := newTritonDiscovery(conf)
+	td, m, _ := newTritonDiscovery(conf)
 
 	_, err := td.refresh(context.Background())
 	require.Error(t, err)
 	require.True(t, strings.Contains(err.Error(), "an error occurred when requesting targets from the discovery endpoint"))
+	m.Unregister()
 }
 
 func TestTritonSDRefreshCancelled(t *testing.T) {
-	td, _ := newTritonDiscovery(conf)
+	td, m, _ := newTritonDiscovery(conf)
 
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 	_, err := td.refresh(ctx)
 	require.Error(t, err)
 	require.True(t, strings.Contains(err.Error(), context.Canceled.Error()))
+	m.Unregister()
 }
 
 func TestTritonSDRefreshCNsUUIDOnly(t *testing.T) {
@@ -211,7 +232,7 @@ func TestTritonSDRefreshCNsWithHostname(t *testing.T) {
 
 func testTritonSDRefresh(t *testing.T, c SDConfig, dstr string) []model.LabelSet {
 	var (
-		td, _ = newTritonDiscovery(c)
+		td, m, _ = newTritonDiscovery(c)
 		s        = httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			fmt.Fprintln(w, dstr)
 		}))
@@ -240,5 +261,7 @@ func testTritonSDRefresh(t *testing.T, c SDConfig, dstr string) []model.LabelSet
 	tg := tgs[0]
 	require.NotNil(t, tg)
 
+	m.Unregister()
+
 	return tg.Targets
 }

discovery/uyuni/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 uyuni
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*uyuniMetrics)(nil)
+
+type uyuniMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *uyuniMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *uyuniMetrics) Unregister() {}

discovery/uyuni/uyuni.go

@@ -111,12 +111,19 @@ type Discovery struct {
 	logger          log.Logger
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &uyuniMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -204,7 +211,12 @@ func getEndpointInfoForSystems(
 }
 
 // NewDiscovery returns a uyuni discovery for the given configuration.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*uyuniMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	apiURL, err := url.Parse(conf.Server)
 	if err != nil {
 		return nil, err
@@ -233,7 +245,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "uyuni",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/uyuni/uyuni_test.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -37,7 +38,17 @@ func testUpdateServices(respHandler http.HandlerFunc) ([]*targetgroup.Group, err
 		Server: ts.URL,
 	}
 
-	md, err := NewDiscovery(&conf, nil, prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := conf.NewDiscovererMetrics(reg, refreshMetrics)
+	err := metrics.Register()
+	if err != nil {
+		return nil, err
+	}
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	md, err := NewDiscovery(&conf, nil, metrics)
 	if err != nil {
 		return nil, err
 	}
@@ -110,7 +121,14 @@ func TestUyuniSDSkipLogin(t *testing.T) {
 		Server: ts.URL,
 	}
 
-	md, err := NewDiscovery(&conf, nil, prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := conf.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	md, err := NewDiscovery(&conf, nil, metrics)
 	if err != nil {
 		t.Error(err)
 	}

discovery/vultr/metrics.go

@@ -0,0 +1,32 @@
+// Copyright 2015 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 vultr
+
+import (
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*vultrMetrics)(nil)
+
+type vultrMetrics struct {
+	refreshMetrics discovery.RefreshMetricsInstantiator
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *vultrMetrics) Register() error {
+	return nil
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *vultrMetrics) Unregister() {}

discovery/vultr/vultr.go

@@ -74,12 +74,19 @@ type SDConfig struct {
 	Port            int            `yaml:"port"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*SDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &vultrMetrics{
+		refreshMetrics: rmi,
+	}
+}
+
 // Name returns the name of the Config.
 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, opts.Registerer)
+	return NewDiscovery(c, opts.Logger, opts.Metrics)
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -107,7 +114,12 @@ type Discovery struct {
 }
 
 // NewDiscovery returns a new Discovery which periodically refreshes its targets.
-func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer) (*Discovery, error) {
+func NewDiscovery(conf *SDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (*Discovery, error) {
+	m, ok := metrics.(*vultrMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	d := &Discovery{
 		port: conf.Port,
 	}
@@ -134,7 +146,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, reg prometheus.Registerer)
 			Mech:                "vultr",
 			Interval:            time.Duration(conf.RefreshInterval),
 			RefreshF:            d.refresh,
-			Registry: reg,
+			MetricsInstantiator: m.refreshMetrics,
 		},
 	)
 	return d, nil

discovery/vultr/vultr_test.go

@@ -23,6 +23,8 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
+
+	"github.com/prometheus/prometheus/discovery"
 )
 
 type VultrSDTestSuite struct {
@@ -47,7 +49,15 @@ func TestVultrSDRefresh(t *testing.T) {
 
 	cfg := DefaultSDConfig
 	cfg.HTTPClientConfig.BearerToken = APIKey
-	d, err := NewDiscovery(&cfg, log.NewNopLogger(), prometheus.NewRegistry())
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	defer metrics.Unregister()
+	defer refreshMetrics.Unregister()
+
+	d, err := NewDiscovery(&cfg, log.NewNopLogger(), metrics)
 	require.NoError(t, err)
 	endpoint, err := url.Parse(sdMock.Mock.Endpoint())
 	require.NoError(t, err)

discovery/xds/kuma.go

@@ -58,6 +58,11 @@ const (
 
 type KumaSDConfig = SDConfig
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*KumaSDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return newDiscovererMetrics(reg, rmi)
+}
+
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
 func (c *KumaSDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	*c = DefaultKumaSDConfig
@@ -97,7 +102,7 @@ func (c *KumaSDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discover
 		logger = log.NewNopLogger()
 	}
 
-	return NewKumaHTTPDiscovery(c, logger, opts.Registerer)
+	return NewKumaHTTPDiscovery(c, logger, opts.Metrics)
 }
 
 func convertKumaV1MonitoringAssignment(assignment *MonitoringAssignment) []model.LabelSet {
@@ -153,7 +158,12 @@ func kumaMadsV1ResourceParser(resources []*anypb.Any, typeURL string) ([]model.L
 	return targets, nil
 }
 
-func NewKumaHTTPDiscovery(conf *KumaSDConfig, logger log.Logger, reg prometheus.Registerer) (discovery.Discoverer, error) {
+func NewKumaHTTPDiscovery(conf *KumaSDConfig, logger log.Logger, metrics discovery.DiscovererMetrics) (discovery.Discoverer, error) {
+	m, ok := metrics.(*xdsMetrics)
+	if !ok {
+		return nil, fmt.Errorf("invalid discovery metrics type")
+	}
+
 	// Default to "prometheus" if hostname is unavailable.
 	clientID := conf.ClientID
 	if clientID == "" {
@@ -189,36 +199,8 @@ func NewKumaHTTPDiscovery(conf *KumaSDConfig, logger log.Logger, reg prometheus.
 		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},
-			},
-		),
+		metrics:         m,
 	}
 
-	d.metricRegisterer = discovery.NewMetricRegisterer(
-		reg,
-		[]prometheus.Collector{
-			d.fetchFailuresCount,
-			d.fetchSkipUpdateCount,
-			d.fetchDuration,
-		},
-	)
-
 	return d, nil
 }

discovery/xds/kuma_test.go

@@ -28,6 +28,7 @@ import (
 	"google.golang.org/protobuf/types/known/anypb"
 	"gopkg.in/yaml.v2"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -108,7 +109,16 @@ func getKumaMadsV1DiscoveryResponse(resources ...*MonitoringAssignment) (*v3.Dis
 }
 
 func newKumaTestHTTPDiscovery(c KumaSDConfig) (*fetchDiscovery, error) {
-	kd, err := NewKumaHTTPDiscovery(&c, nopLogger, prometheus.NewRegistry())
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	// TODO(ptodev): Add the ability to unregister refresh metrics.
+	metrics := c.NewDiscovererMetrics(reg, refreshMetrics)
+	err := metrics.Register()
+	if err != nil {
+		return nil, err
+	}
+
+	kd, err := NewKumaHTTPDiscovery(&c, nopLogger, metrics)
 	if err != nil {
 		return nil, err
 	}
@@ -207,6 +217,8 @@ func TestNewKumaHTTPDiscovery(t *testing.T) {
 	require.Equal(t, KumaMadsV1ResourceTypeURL, resClient.ResourceTypeURL())
 	require.Equal(t, kumaConf.ClientID, resClient.ID())
 	require.Equal(t, KumaMadsV1ResourceType, resClient.config.ResourceType)
+
+	kd.metrics.Unregister()
 }
 
 func TestKumaHTTPDiscoveryRefresh(t *testing.T) {
@@ -301,4 +313,6 @@ tls_config:
 	case <-ch:
 		require.Fail(t, "no update expected")
 	}
+
+	kd.metrics.Unregister()
 }

discovery/xds/metrics.go

@@ -0,0 +1,73 @@
+// Copyright 2015 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 xds
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/prometheus/prometheus/discovery"
+)
+
+var _ discovery.DiscovererMetrics = (*xdsMetrics)(nil)
+
+type xdsMetrics struct {
+	fetchDuration        prometheus.Summary
+	fetchSkipUpdateCount prometheus.Counter
+	fetchFailuresCount   prometheus.Counter
+
+	metricRegisterer discovery.MetricRegisterer
+}
+
+func newDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	m := &xdsMetrics{
+		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},
+			},
+		),
+	}
+
+	m.metricRegisterer = discovery.NewMetricRegisterer(reg, []prometheus.Collector{
+		m.fetchFailuresCount,
+		m.fetchSkipUpdateCount,
+		m.fetchDuration,
+	})
+
+	return m
+}
+
+// Register implements discovery.DiscovererMetrics.
+func (m *xdsMetrics) Register() error {
+	return m.metricRegisterer.RegisterMetrics()
+}
+
+// Unregister implements discovery.DiscovererMetrics.
+func (m *xdsMetrics) Unregister() {
+	m.metricRegisterer.UnregisterMetrics()
+}

discovery/xds/xds.go

@@ -20,7 +20,6 @@ import (
 	v3 "github.com/envoyproxy/go-control-plane/envoy/service/discovery/v3"
 	"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"
 	"google.golang.org/protobuf/encoding/protojson"
@@ -107,20 +106,10 @@ type fetchDiscovery struct {
 	parseResources resourceParser
 	logger         log.Logger
 
-	fetchDuration        prometheus.Summary
-	fetchSkipUpdateCount prometheus.Counter
-	fetchFailuresCount   prometheus.Counter
-
-	metricRegisterer discovery.MetricRegisterer
+	metrics *xdsMetrics
 }
 
 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)
@@ -141,7 +130,7 @@ func (d *fetchDiscovery) poll(ctx context.Context, ch chan<- []*targetgroup.Grou
 	t0 := time.Now()
 	response, err := d.client.Fetch(ctx)
 	elapsed := time.Since(t0)
-	d.fetchDuration.Observe(elapsed.Seconds())
+	d.metrics.fetchDuration.Observe(elapsed.Seconds())
 
 	// Check the context before in order to exit early.
 	select {
@@ -152,20 +141,20 @@ func (d *fetchDiscovery) poll(ctx context.Context, ch chan<- []*targetgroup.Grou
 
 	if err != nil {
 		level.Error(d.logger).Log("msg", "error parsing resources", "err", err)
-		d.fetchFailuresCount.Inc()
+		d.metrics.fetchFailuresCount.Inc()
 		return
 	}
 
 	if response == nil {
 		// No update needed.
-		d.fetchSkipUpdateCount.Inc()
+		d.metrics.fetchSkipUpdateCount.Inc()
 		return
 	}
 
 	parsedTargets, err := d.parseResources(response.Resources, response.TypeUrl)
 	if err != nil {
 		level.Error(d.logger).Log("msg", "error parsing resources", "err", err)
-		d.fetchFailuresCount.Inc()
+		d.metrics.fetchFailuresCount.Inc()
 		return
 	}
 

discovery/xds/xds_test.go

@@ -29,24 +29,15 @@ import (
 	"go.uber.org/goleak"
 	"google.golang.org/protobuf/types/known/anypb"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
-var (
-	sdConf = SDConfig{
+var sdConf = SDConfig{
 	Server:          "http://127.0.0.1",
 	RefreshInterval: model.Duration(10 * time.Second),
 	ClientID:        "test-id",
-	}
-
-	testFetchFailuresCount = prometheus.NewCounter(
-		prometheus.CounterOpts{})
-	testFetchSkipUpdateCount = prometheus.NewCounter(
-		prometheus.CounterOpts{})
-	testFetchDuration = prometheus.NewSummary(
-		prometheus.SummaryOpts{},
-	)
-)
+}
 
 func TestMain(m *testing.M) {
 	goleak.VerifyTestMain(m)
@@ -133,12 +124,22 @@ func TestPollingRefreshSkipUpdate(t *testing.T) {
 			return nil, nil
 		},
 	}
+
+	cfg := &SDConfig{}
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	xdsMetrics, ok := metrics.(*xdsMetrics)
+	if !ok {
+		require.Fail(t, "invalid discovery metrics type")
+	}
+
 	pd := &fetchDiscovery{
 		client:  rc,
 		logger:  nopLogger,
-		fetchDuration:        testFetchDuration,
-		fetchFailuresCount:   testFetchFailuresCount,
-		fetchSkipUpdateCount: testFetchSkipUpdateCount,
+		metrics: xdsMetrics,
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
@@ -155,6 +156,9 @@ func TestPollingRefreshSkipUpdate(t *testing.T) {
 	case <-ch:
 		require.Fail(t, "no update expected")
 	}
+
+	metrics.Unregister()
+	refreshMetrics.Unregister()
 }
 
 func TestPollingRefreshAttachesGroupMetadata(t *testing.T) {
@@ -167,13 +171,18 @@ func TestPollingRefreshAttachesGroupMetadata(t *testing.T) {
 			return &v3.DiscoveryResponse{}, nil
 		},
 	}
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := newDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+	xdsMetrics, ok := metrics.(*xdsMetrics)
+	require.True(t, ok)
+
 	pd := &fetchDiscovery{
 		source: source,
 		client: rc,
 		logger: nopLogger,
-		fetchDuration:        testFetchDuration,
-		fetchFailuresCount:   testFetchFailuresCount,
-		fetchSkipUpdateCount: testFetchSkipUpdateCount,
 		parseResources: constantResourceParser([]model.LabelSet{
 			{
 				"__meta_custom_xds_label": "a-value",
@@ -186,6 +195,7 @@ func TestPollingRefreshAttachesGroupMetadata(t *testing.T) {
 				"instance":                "prometheus-02",
 			},
 		}, nil),
+		metrics: xdsMetrics,
 	}
 	ch := make(chan []*targetgroup.Group, 1)
 	pd.poll(context.Background(), ch)
@@ -202,6 +212,9 @@ func TestPollingRefreshAttachesGroupMetadata(t *testing.T) {
 	target2 := group.Targets[1]
 	require.Contains(t, target2, model.LabelName("__meta_custom_xds_label"))
 	require.Equal(t, model.LabelValue("a-value"), target2["__meta_custom_xds_label"])
+
+	metrics.Unregister()
+	refreshMetrics.Unregister()
 }
 
 func TestPollingDisappearingTargets(t *testing.T) {
@@ -243,14 +256,23 @@ func TestPollingDisappearingTargets(t *testing.T) {
 		}, nil
 	}
 
+	cfg := &SDConfig{}
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	metrics := cfg.NewDiscovererMetrics(reg, refreshMetrics)
+	require.NoError(t, metrics.Register())
+
+	xdsMetrics, ok := metrics.(*xdsMetrics)
+	if !ok {
+		require.Fail(t, "invalid discovery metrics type")
+	}
+
 	pd := &fetchDiscovery{
 		source:         source,
 		client:         rc,
 		logger:         nopLogger,
-		fetchDuration:        testFetchDuration,
-		fetchFailuresCount:   testFetchFailuresCount,
-		fetchSkipUpdateCount: testFetchSkipUpdateCount,
 		parseResources: parser,
+		metrics:        xdsMetrics,
 	}
 
 	ch := make(chan []*targetgroup.Group, 1)
@@ -271,4 +293,7 @@ func TestPollingDisappearingTargets(t *testing.T) {
 
 	require.Equal(t, source, groups[0].Source)
 	require.Len(t, groups[0].Targets, 1)
+
+	metrics.Unregister()
+	refreshMetrics.Unregister()
 }

discovery/zookeeper/zookeeper.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-zookeeper/zk"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 
 	"github.com/prometheus/prometheus/discovery"
@@ -56,6 +57,11 @@ type ServersetSDConfig struct {
 	Timeout model.Duration `yaml:"timeout,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*ServersetSDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &discovery.NoopDiscovererMetrics{}
+}
+
 // Name returns the name of the Config.
 func (*ServersetSDConfig) Name() string { return "serverset" }
 
@@ -93,6 +99,11 @@ type NerveSDConfig struct {
 	Timeout model.Duration `yaml:"timeout,omitempty"`
 }
 
+// NewDiscovererMetrics implements discovery.Config.
+func (*NerveSDConfig) NewDiscovererMetrics(reg prometheus.Registerer, rmi discovery.RefreshMetricsInstantiator) discovery.DiscovererMetrics {
+	return &discovery.NoopDiscovererMetrics{}
+}
+
 // Name returns the name of the Config.
 func (*NerveSDConfig) Name() string { return "nerve" }
 

documentation/examples/custom-sd/adapter-usage/main.go

@@ -28,8 +28,10 @@ import (
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 
+	prom_discovery "github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 	"github.com/prometheus/prometheus/documentation/examples/custom-sd/adapter"
 	"github.com/prometheus/prometheus/util/strutil"
@@ -273,7 +275,16 @@ func main() {
 		level.Error(logger).Log("msg", "failed to create discovery metrics", "err", err)
 		os.Exit(1)
 	}
-	sdAdapter := adapter.NewAdapter(ctx, *outputFile, "exampleSD", disc, logger)
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := prom_discovery.NewRefreshMetrics(reg)
+	metrics, err := prom_discovery.RegisterSDMetrics(reg, refreshMetrics)
+	if err != nil {
+		level.Error(logger).Log("msg", "failed to register service discovery metrics", "err", err)
+		os.Exit(1)
+	}
+
+	sdAdapter := adapter.NewAdapter(ctx, *outputFile, "exampleSD", disc, logger, metrics, reg)
 	sdAdapter.Run()
 
 	<-ctx.Done()

documentation/examples/custom-sd/adapter/adapter.go

@@ -163,12 +163,12 @@ func (a *Adapter) Run() {
 }
 
 // NewAdapter creates a new instance of Adapter.
-func NewAdapter(ctx context.Context, file, name string, d discovery.Discoverer, logger log.Logger) *Adapter {
+func NewAdapter(ctx context.Context, file, name string, d discovery.Discoverer, logger log.Logger, sdMetrics map[string]discovery.DiscovererMetrics, registerer prometheus.Registerer) *Adapter {
 	return &Adapter{
 		ctx:     ctx,
 		disc:    d,
 		groups:  make(map[string]*customSD),
-		manager: discovery.NewManager(ctx, logger, prometheus.NewRegistry()),
+		manager: discovery.NewManager(ctx, logger, registerer, sdMetrics),
 		output:  file,
 		name:    name,
 		logger:  logger,

documentation/examples/custom-sd/adapter/adapter_test.go

@@ -18,9 +18,11 @@ import (
 	"os"
 	"testing"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 
+	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 )
 
@@ -227,6 +229,12 @@ func TestWriteOutput(t *testing.T) {
 	defer os.Remove(tmpfile.Name())
 	tmpfile.Close()
 	require.NoError(t, err)
-	adapter := NewAdapter(ctx, tmpfile.Name(), "test_sd", nil, nil)
+
+	reg := prometheus.NewRegistry()
+	refreshMetrics := discovery.NewRefreshMetrics(reg)
+	sdMetrics, err := discovery.RegisterSDMetrics(reg, refreshMetrics)
+	require.NoError(t, err)
+
+	adapter := NewAdapter(ctx, tmpfile.Name(), "test_sd", nil, nil, sdMetrics, reg)
 	require.NoError(t, adapter.writeOutput())
 }