config: remove expand-external-labels flag in release 3.0 (#14657)

remove expand-external-labels feature flag

and enabled env arg expansion for external labels by default.

Signed-off-by: jyz0309 <45495947@qq.com>

cmd/prometheus/main.go

@@ -200,11 +200,10 @@ type flagConfig struct {
 	memlimitRatio float64
 	// These options are extracted from featureList
 	// for ease of use.
-	enableExpandExternalLabels bool
+	enablePerStepStats       bool
-	enablePerStepStats         bool
+	enableAutoGOMAXPROCS     bool
-	enableAutoGOMAXPROCS       bool
+	enableAutoGOMEMLIMIT     bool
-	enableAutoGOMEMLIMIT       bool
+	enableConcurrentRuleEval bool
-	enableConcurrentRuleEval   bool
 
 	prometheusURL   string
 	corsRegexString string
@@ -220,9 +219,6 @@ func (c *flagConfig) setFeatureListOptions(logger *slog.Logger) error {
 		opts := strings.Split(f, ",")
 		for _, o := range opts {
 			switch o {
-			case "expand-external-labels":
-				c.enableExpandExternalLabels = true
-				logger.Info("Experimental expand-external-labels enabled")
 			case "exemplar-storage":
 				c.tsdb.EnableExemplarStorage = true
 				logger.Info("Experimental in-memory exemplar storage enabled")
@@ -595,7 +591,7 @@ func main() {
 
 	// Throw error for invalid config before starting other components.
 	var cfgFile *config.Config
-	if cfgFile, err = config.LoadFile(cfg.configFile, agentMode, false, promslog.NewNopLogger()); err != nil {
+	if cfgFile, err = config.LoadFile(cfg.configFile, agentMode, promslog.NewNopLogger()); err != nil {
 		absPath, pathErr := filepath.Abs(cfg.configFile)
 		if pathErr != nil {
 			absPath = cfg.configFile
@@ -1145,7 +1141,7 @@ func main() {
 				for {
 					select {
 					case <-hup:
-						if err := reloadConfig(cfg.configFile, cfg.enableExpandExternalLabels, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, callback, reloaders...); err != nil {
+						if err := reloadConfig(cfg.configFile, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, callback, reloaders...); err != nil {
 							logger.Error("Error reloading config", "err", err)
 						} else if cfg.enableAutoReload {
 							if currentChecksum, err := config.GenerateChecksum(cfg.configFile); err == nil {
@@ -1155,7 +1151,7 @@ func main() {
 							}
 						}
 					case rc := <-webHandler.Reload():
-						if err := reloadConfig(cfg.configFile, cfg.enableExpandExternalLabels, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, callback, reloaders...); err != nil {
+						if err := reloadConfig(cfg.configFile, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, callback, reloaders...); err != nil {
 							logger.Error("Error reloading config", "err", err)
 							rc <- err
 						} else {
@@ -1180,7 +1176,7 @@ func main() {
 						}
 						logger.Info("Configuration file change detected, reloading the configuration.")
 
-						if err := reloadConfig(cfg.configFile, cfg.enableExpandExternalLabels, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, callback, reloaders...); err != nil {
+						if err := reloadConfig(cfg.configFile, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, callback, reloaders...); err != nil {
 							logger.Error("Error reloading config", "err", err)
 						} else {
 							checksum = currentChecksum
@@ -1210,7 +1206,7 @@ func main() {
 					return nil
 				}
 
-				if err := reloadConfig(cfg.configFile, cfg.enableExpandExternalLabels, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, func(bool) {}, reloaders...); err != nil {
+				if err := reloadConfig(cfg.configFile, cfg.tsdb.EnableExemplarStorage, logger, noStepSubqueryInterval, func(bool) {}, reloaders...); err != nil {
 					return fmt.Errorf("error loading config from %q: %w", cfg.configFile, err)
 				}
 
@@ -1437,7 +1433,7 @@ type reloader struct {
 	reloader func(*config.Config) error
 }
 
-func reloadConfig(filename string, expandExternalLabels, enableExemplarStorage bool, logger *slog.Logger, noStepSuqueryInterval *safePromQLNoStepSubqueryInterval, callback func(bool), rls ...reloader) (err error) {
+func reloadConfig(filename string, enableExemplarStorage bool, logger *slog.Logger, noStepSuqueryInterval *safePromQLNoStepSubqueryInterval, callback func(bool), rls ...reloader) (err error) {
 	start := time.Now()
 	timingsLogger := logger
 	logger.Info("Loading configuration file", "filename", filename)
@@ -1453,7 +1449,7 @@ func reloadConfig(filename string, expandExternalLabels, enableExemplarStorage b
 		}
 	}()
 
-	conf, err := config.LoadFile(filename, agentMode, expandExternalLabels, logger)
+	conf, err := config.LoadFile(filename, agentMode, logger)
 	if err != nil {
 		return fmt.Errorf("couldn't load configuration (--config.file=%q): %w", filename, err)
 	}

cmd/promtool/main.go

@@ -575,7 +575,7 @@ func checkFileExists(fn string) error {
 func checkConfig(agentMode bool, filename string, checkSyntaxOnly bool) ([]string, error) {
 	fmt.Println("Checking", filename)
 
-	cfg, err := config.LoadFile(filename, agentMode, false, promslog.NewNopLogger())
+	cfg, err := config.LoadFile(filename, agentMode, promslog.NewNopLogger())
 	if err != nil {
 		return nil, err
 	}

cmd/promtool/sd.go

@@ -41,7 +41,7 @@ type sdCheckResult struct {
 func CheckSD(sdConfigFiles, sdJobName string, sdTimeout time.Duration, registerer prometheus.Registerer) int {
 	logger := promslog.New(&promslog.Config{})
 
-	cfg, err := config.LoadFile(sdConfigFiles, false, false, logger)
+	cfg, err := config.LoadFile(sdConfigFiles, false, logger)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "Cannot load config", err)
 		return failureExitCode

config/config.go

@@ -72,7 +72,7 @@ const (
 )
 
 // Load parses the YAML input s into a Config.
-func Load(s string, expandExternalLabels bool, logger *slog.Logger) (*Config, error) {
+func Load(s string, logger *slog.Logger) (*Config, error) {
 	cfg := &Config{}
 	// If the entire config body is empty the UnmarshalYAML method is
 	// never called. We thus have to set the DefaultConfig at the entry
@@ -84,10 +84,6 @@ func Load(s string, expandExternalLabels bool, logger *slog.Logger) (*Config, er
 		return nil, err
 	}
 
-	if !expandExternalLabels {
-		return cfg, nil
-	}
-
 	b := labels.NewScratchBuilder(0)
 	cfg.GlobalConfig.ExternalLabels.Range(func(v labels.Label) {
 		newV := os.Expand(v.Value, func(s string) string {
@@ -106,17 +102,19 @@ func Load(s string, expandExternalLabels bool, logger *slog.Logger) (*Config, er
 		// Note newV can be blank. https://github.com/prometheus/prometheus/issues/11024
 		b.Add(v.Name, newV)
 	})
-	cfg.GlobalConfig.ExternalLabels = b.Labels()
+	if !b.Labels().IsEmpty() {
+		cfg.GlobalConfig.ExternalLabels = b.Labels()
+	}
 	return cfg, nil
 }
 
 // LoadFile parses the given YAML file into a Config.
-func LoadFile(filename string, agentMode, expandExternalLabels bool, logger *slog.Logger) (*Config, error) {
+func LoadFile(filename string, agentMode bool, logger *slog.Logger) (*Config, error) {
 	content, err := os.ReadFile(filename)
 	if err != nil {
 		return nil, err
 	}
-	cfg, err := Load(string(content), expandExternalLabels, logger)
+	cfg, err := Load(string(content), logger)
 	if err != nil {
 		return nil, fmt.Errorf("parsing YAML file %s: %w", filename, err)
 	}

config/config_test.go

@@ -1501,7 +1501,7 @@ var expectedConf = &Config{
 }
 
 func TestYAMLRoundtrip(t *testing.T) {
-	want, err := LoadFile("testdata/roundtrip.good.yml", false, false, promslog.NewNopLogger())
+	want, err := LoadFile("testdata/roundtrip.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 
 	out, err := yaml.Marshal(want)
@@ -1514,7 +1514,7 @@ func TestYAMLRoundtrip(t *testing.T) {
 }
 
 func TestRemoteWriteRetryOnRateLimit(t *testing.T) {
-	want, err := LoadFile("testdata/remote_write_retry_on_rate_limit.good.yml", false, false, promslog.NewNopLogger())
+	want, err := LoadFile("testdata/remote_write_retry_on_rate_limit.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 
 	out, err := yaml.Marshal(want)
@@ -1529,7 +1529,7 @@ func TestRemoteWriteRetryOnRateLimit(t *testing.T) {
 
 func TestOTLPSanitizeResourceAttributes(t *testing.T) {
 	t.Run("good config", func(t *testing.T) {
-		want, err := LoadFile(filepath.Join("testdata", "otlp_sanitize_resource_attributes.good.yml"), false, false, promslog.NewNopLogger())
+		want, err := LoadFile(filepath.Join("testdata", "otlp_sanitize_resource_attributes.good.yml"), false, promslog.NewNopLogger())
 		require.NoError(t, err)
 
 		out, err := yaml.Marshal(want)
@@ -1541,7 +1541,7 @@ func TestOTLPSanitizeResourceAttributes(t *testing.T) {
 	})
 
 	t.Run("bad config", func(t *testing.T) {
-		_, err := LoadFile(filepath.Join("testdata", "otlp_sanitize_resource_attributes.bad.yml"), false, false, promslog.NewNopLogger())
+		_, err := LoadFile(filepath.Join("testdata", "otlp_sanitize_resource_attributes.bad.yml"), false, promslog.NewNopLogger())
 		require.ErrorContains(t, err, `duplicated promoted OTel resource attribute "k8s.job.name"`)
 		require.ErrorContains(t, err, `empty promoted OTel resource attribute`)
 	})
@@ -1550,16 +1550,17 @@ func TestOTLPSanitizeResourceAttributes(t *testing.T) {
 func TestLoadConfig(t *testing.T) {
 	// Parse a valid file that sets a global scrape timeout. This tests whether parsing
 	// an overwritten default field in the global config permanently changes the default.
-	_, err := LoadFile("testdata/global_timeout.good.yml", false, false, promslog.NewNopLogger())
+	_, err := LoadFile("testdata/global_timeout.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 
-	c, err := LoadFile("testdata/conf.good.yml", false, false, promslog.NewNopLogger())
+	c, err := LoadFile("testdata/conf.good.yml", false, promslog.NewNopLogger())
+
 	require.NoError(t, err)
 	require.Equal(t, expectedConf, c)
 }
 
 func TestScrapeIntervalLarger(t *testing.T) {
-	c, err := LoadFile("testdata/scrape_interval_larger.good.yml", false, false, promslog.NewNopLogger())
+	c, err := LoadFile("testdata/scrape_interval_larger.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 	require.Len(t, c.ScrapeConfigs, 1)
 	for _, sc := range c.ScrapeConfigs {
@@ -1569,7 +1570,7 @@ func TestScrapeIntervalLarger(t *testing.T) {
 
 // YAML marshaling must not reveal authentication credentials.
 func TestElideSecrets(t *testing.T) {
-	c, err := LoadFile("testdata/conf.good.yml", false, false, promslog.NewNopLogger())
+	c, err := LoadFile("testdata/conf.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 
 	secretRe := regexp.MustCompile(`\\u003csecret\\u003e|<secret>`)
@@ -1586,31 +1587,31 @@ func TestElideSecrets(t *testing.T) {
 
 func TestLoadConfigRuleFilesAbsolutePath(t *testing.T) {
 	// Parse a valid file that sets a rule files with an absolute path
-	c, err := LoadFile(ruleFilesConfigFile, false, false, promslog.NewNopLogger())
+	c, err := LoadFile(ruleFilesConfigFile, false, promslog.NewNopLogger())
 	require.NoError(t, err)
 	require.Equal(t, ruleFilesExpectedConf, c)
 }
 
 func TestKubernetesEmptyAPIServer(t *testing.T) {
-	_, err := LoadFile("testdata/kubernetes_empty_apiserver.good.yml", false, false, promslog.NewNopLogger())
+	_, err := LoadFile("testdata/kubernetes_empty_apiserver.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 }
 
 func TestKubernetesWithKubeConfig(t *testing.T) {
-	_, err := LoadFile("testdata/kubernetes_kubeconfig_without_apiserver.good.yml", false, false, promslog.NewNopLogger())
+	_, err := LoadFile("testdata/kubernetes_kubeconfig_without_apiserver.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 }
 
 func TestKubernetesSelectors(t *testing.T) {
-	_, err := LoadFile("testdata/kubernetes_selectors_endpoints.good.yml", false, false, promslog.NewNopLogger())
+	_, err := LoadFile("testdata/kubernetes_selectors_endpoints.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
-	_, err = LoadFile("testdata/kubernetes_selectors_node.good.yml", false, false, promslog.NewNopLogger())
+	_, err = LoadFile("testdata/kubernetes_selectors_node.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
-	_, err = LoadFile("testdata/kubernetes_selectors_ingress.good.yml", false, false, promslog.NewNopLogger())
+	_, err = LoadFile("testdata/kubernetes_selectors_ingress.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
-	_, err = LoadFile("testdata/kubernetes_selectors_pod.good.yml", false, false, promslog.NewNopLogger())
+	_, err = LoadFile("testdata/kubernetes_selectors_pod.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
-	_, err = LoadFile("testdata/kubernetes_selectors_service.good.yml", false, false, promslog.NewNopLogger())
+	_, err = LoadFile("testdata/kubernetes_selectors_service.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 }
 
@@ -2094,7 +2095,7 @@ func TestBadConfigs(t *testing.T) {
 		model.NameValidationScheme = model.UTF8Validation
 	}()
 	for _, ee := range expectedErrors {
-		_, err := LoadFile("testdata/"+ee.filename, false, false, promslog.NewNopLogger())
+		_, err := LoadFile("testdata/"+ee.filename, false, promslog.NewNopLogger())
 		require.ErrorContains(t, err, ee.errMsg,
 			"Expected error for %s to contain %q but got: %s", ee.filename, ee.errMsg, err)
 	}
@@ -2125,7 +2126,7 @@ func TestBadStaticConfigsYML(t *testing.T) {
 }
 
 func TestEmptyConfig(t *testing.T) {
-	c, err := Load("", false, promslog.NewNopLogger())
+	c, err := Load("", promslog.NewNopLogger())
 	require.NoError(t, err)
 	exp := DefaultConfig
 	require.Equal(t, exp, *c)
@@ -2135,38 +2136,34 @@ func TestExpandExternalLabels(t *testing.T) {
 	// Cleanup ant TEST env variable that could exist on the system.
 	os.Setenv("TEST", "")
 
-	c, err := LoadFile("testdata/external_labels.good.yml", false, false, promslog.NewNopLogger())
+	c, err := LoadFile("testdata/external_labels.good.yml", false, promslog.NewNopLogger())
-	require.NoError(t, err)
-	testutil.RequireEqual(t, labels.FromStrings("bar", "foo", "baz", "foo${TEST}bar", "foo", "${TEST}", "qux", "foo$${TEST}", "xyz", "foo$$bar"), c.GlobalConfig.ExternalLabels)
-
-	c, err = LoadFile("testdata/external_labels.good.yml", false, true, promslog.NewNopLogger())
 	require.NoError(t, err)
 	testutil.RequireEqual(t, labels.FromStrings("bar", "foo", "baz", "foobar", "foo", "", "qux", "foo${TEST}", "xyz", "foo$bar"), c.GlobalConfig.ExternalLabels)
 
 	os.Setenv("TEST", "TestValue")
-	c, err = LoadFile("testdata/external_labels.good.yml", false, true, promslog.NewNopLogger())
+	c, err = LoadFile("testdata/external_labels.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 	testutil.RequireEqual(t, labels.FromStrings("bar", "foo", "baz", "fooTestValuebar", "foo", "TestValue", "qux", "foo${TEST}", "xyz", "foo$bar"), c.GlobalConfig.ExternalLabels)
 }
 
 func TestAgentMode(t *testing.T) {
-	_, err := LoadFile("testdata/agent_mode.with_alert_manager.yml", true, false, promslog.NewNopLogger())
+	_, err := LoadFile("testdata/agent_mode.with_alert_manager.yml", true, promslog.NewNopLogger())
 	require.ErrorContains(t, err, "field alerting is not allowed in agent mode")
 
-	_, err = LoadFile("testdata/agent_mode.with_alert_relabels.yml", true, false, promslog.NewNopLogger())
+	_, err = LoadFile("testdata/agent_mode.with_alert_relabels.yml", true, promslog.NewNopLogger())
 	require.ErrorContains(t, err, "field alerting is not allowed in agent mode")
 
-	_, err = LoadFile("testdata/agent_mode.with_rule_files.yml", true, false, promslog.NewNopLogger())
+	_, err = LoadFile("testdata/agent_mode.with_rule_files.yml", true, promslog.NewNopLogger())
 	require.ErrorContains(t, err, "field rule_files is not allowed in agent mode")
 
-	_, err = LoadFile("testdata/agent_mode.with_remote_reads.yml", true, false, promslog.NewNopLogger())
+	_, err = LoadFile("testdata/agent_mode.with_remote_reads.yml", true, promslog.NewNopLogger())
 	require.ErrorContains(t, err, "field remote_read is not allowed in agent mode")
 
-	c, err := LoadFile("testdata/agent_mode.without_remote_writes.yml", true, false, promslog.NewNopLogger())
+	c, err := LoadFile("testdata/agent_mode.without_remote_writes.yml", true, promslog.NewNopLogger())
 	require.NoError(t, err)
 	require.Empty(t, c.RemoteWriteConfigs)
 
-	c, err = LoadFile("testdata/agent_mode.good.yml", true, false, promslog.NewNopLogger())
+	c, err = LoadFile("testdata/agent_mode.good.yml", true, promslog.NewNopLogger())
 	require.NoError(t, err)
 	require.Len(t, c.RemoteWriteConfigs, 1)
 	require.Equal(
@@ -2177,7 +2174,7 @@ func TestAgentMode(t *testing.T) {
 }
 
 func TestEmptyGlobalBlock(t *testing.T) {
-	c, err := Load("global:\n", false, promslog.NewNopLogger())
+	c, err := Load("global:\n", promslog.NewNopLogger())
 	require.NoError(t, err)
 	exp := DefaultConfig
 	exp.Runtime = DefaultRuntimeConfig
@@ -2332,7 +2329,7 @@ func TestGetScrapeConfigs(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			c, err := LoadFile(tc.configFile, false, false, promslog.NewNopLogger())
+			c, err := LoadFile(tc.configFile, false, promslog.NewNopLogger())
 			require.NoError(t, err)
 
 			scfgs, err := c.GetScrapeConfigs()
@@ -2350,7 +2347,7 @@ func kubernetesSDHostURL() config.URL {
 }
 
 func TestScrapeConfigDisableCompression(t *testing.T) {
-	want, err := LoadFile("testdata/scrape_config_disable_compression.good.yml", false, false, promslog.NewNopLogger())
+	want, err := LoadFile("testdata/scrape_config_disable_compression.good.yml", false, promslog.NewNopLogger())
 	require.NoError(t, err)
 
 	out, err := yaml.Marshal(want)
@@ -2397,7 +2394,7 @@ func TestScrapeConfigNameValidationSettings(t *testing.T) {
 
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			want, err := LoadFile(fmt.Sprintf("testdata/%s.yml", tc.inputFile), false, false, promslog.NewNopLogger())
+			want, err := LoadFile(fmt.Sprintf("testdata/%s.yml", tc.inputFile), false, promslog.NewNopLogger())
 			require.NoError(t, err)
 
 			out, err := yaml.Marshal(want)

docs/configuration/configuration.md

@@ -80,6 +80,10 @@ global:
 
   # The labels to add to any time series or alerts when communicating with
   # external systems (federation, remote storage, Alertmanager). 
+  # Environment variable references `${var}` or `$var` are replaced according 
+  # to the values of the current environment variables. 
+  # References to undefined variables are replaced by the empty string.
+  # The `$` character can be escaped by using `$$`.
   external_labels:
     [ <labelname>: <labelvalue> ... ]
 

docs/feature_flags.md

@@ -11,15 +11,6 @@ Their behaviour can change in future releases which will be communicated via the
 You can enable them using the `--enable-feature` flag with a comma separated list of features.
 They may be enabled by default in future versions.
 
-## Expand environment variables in external labels
-
-`--enable-feature=expand-external-labels`
-
-Replace `${var}` or `$var` in the [`external_labels`](configuration/configuration.md#configuration-file)
-values according to the values of the current environment variables. References
-to undefined variables are replaced by the empty string.
-The `$` character can be escaped by using `$$`.
-
 ## Exemplars storage
 
 `--enable-feature=exemplar-storage`

scrape/scrape_test.go

@@ -3835,7 +3835,7 @@ scrape_configs:
 
 	mng, err := NewManager(&Options{DiscoveryReloadInterval: model.Duration(10 * time.Millisecond), EnableNativeHistogramsIngestion: true}, nil, nil, s, reg)
 	require.NoError(t, err)
-	cfg, err := config.Load(configStr, false, promslog.NewNopLogger())
+	cfg, err := config.Load(configStr, promslog.NewNopLogger())
 	require.NoError(t, err)
 	mng.ApplyConfig(cfg)
 	tsets := make(chan map[string][]*targetgroup.Group)