s/scrape_classic_histograms/always_scrape_classic_histograms (3.0 breaking change) (#15178)

This is for readability, especially when we can converting to nhcb option.

See discussion https://cloud-native.slack.com/archives/C077Z4V13AM/p1729155873397889

Signed-off-by: bwplotka <bwplotka@gmail.com>

config/config.go

@@ -163,13 +163,13 @@ var (
 	// DefaultScrapeConfig is the default scrape configuration.
 	DefaultScrapeConfig = ScrapeConfig{
 		// ScrapeTimeout, ScrapeInterval and ScrapeProtocols default to the configured globals.
-		ScrapeClassicHistograms: false,
-		MetricsPath:             "/metrics",
-		Scheme:                  "http",
-		HonorLabels:             false,
-		HonorTimestamps:         true,
-		HTTPClientConfig:        config.DefaultHTTPClientConfig,
-		EnableCompression:       true,
+		AlwaysScrapeClassicHistograms: false,
+		MetricsPath:                   "/metrics",
+		Scheme:                        "http",
+		HonorLabels:                   false,
+		HonorTimestamps:               true,
+		HTTPClientConfig:              config.DefaultHTTPClientConfig,
+		EnableCompression:             true,
 	}
 
 	// DefaultAlertmanagerConfig is the default alertmanager configuration.
@@ -631,8 +631,8 @@ type ScrapeConfig struct {
 	// Supported values (case sensitive): PrometheusProto, OpenMetricsText0.0.1,
 	// OpenMetricsText1.0.0, PrometheusText0.0.4.
 	ScrapeProtocols []ScrapeProtocol `yaml:"scrape_protocols,omitempty"`
-	// Whether to scrape a classic histogram that is also exposed as a native histogram.
-	ScrapeClassicHistograms bool `yaml:"scrape_classic_histograms,omitempty"`
+	// Whether to scrape a classic histogram, even if it is also exposed as a native histogram.
+	AlwaysScrapeClassicHistograms bool `yaml:"always_scrape_classic_histograms,omitempty"`
 	// File to which scrape failures are logged.
 	ScrapeFailureLogFile string `yaml:"scrape_failure_log_file,omitempty"`
 	// The HTTP resource path on which to fetch metrics from targets.

docs/configuration/configuration.md

@@ -215,9 +215,9 @@ job_name: <job_name>
 # OpenMetricsText1.0.0, PrometheusText0.0.4.
 [ scrape_protocols: [<string>, ...] | default = <global_config.scrape_protocols> ]
 
-# Whether to scrape a classic histogram that is also exposed as a native
+# Whether to scrape a classic histogram, even if it is also exposed as a native
 # histogram (has no effect without --enable-feature=native-histograms).
-[ scrape_classic_histograms: <boolean> | default = false ]
+[ always_scrape_classic_histograms: <boolean> | default = false ]
 
 # The HTTP resource path on which to fetch metrics from targets.
 [ metrics_path: <path> | default = /metrics ]

docs/feature_flags.md

@@ -84,7 +84,7 @@ those classic histograms that do not come with a corresponding native
 histogram. However, if a native histogram is present, Prometheus will ignore
 the corresponding classic histogram, with the notable exception of exemplars,
 which are always ingested. To keep the classic histograms as well, enable
-`scrape_classic_histograms` in the scrape job.
+`always_scrape_classic_histograms` in the scrape job.
 
 _Note about the format of `le` and `quantile` label values:_
 

scrape/scrape.go

@@ -112,7 +112,7 @@ type scrapeLoopOptions struct {
 	trackTimestampsStaleness bool
 	interval                 time.Duration
 	timeout                  time.Duration
-	scrapeClassicHistograms  bool
+	alwaysScrapeClassicHist  bool
 	validationScheme         model.ValidationScheme
 
 	mrc               []*relabel.Config
@@ -179,7 +179,7 @@ func newScrapePool(cfg *config.ScrapeConfig, app storage.Appendable, offsetSeed
 			opts.labelLimits,
 			opts.interval,
 			opts.timeout,
-			opts.scrapeClassicHistograms,
+			opts.alwaysScrapeClassicHist,
 			options.EnableNativeHistogramsIngestion,
 			options.EnableCreatedTimestampZeroIngestion,
 			options.ExtraMetrics,
@@ -480,7 +480,7 @@ func (sp *scrapePool) sync(targets []*Target) {
 		enableCompression        = sp.config.EnableCompression
 		trackTimestampsStaleness = sp.config.TrackTimestampsStaleness
 		mrc                      = sp.config.MetricRelabelConfigs
-		scrapeClassicHistograms  = sp.config.ScrapeClassicHistograms
+		alwaysScrapeClassicHist  = sp.config.AlwaysScrapeClassicHistograms
 	)
 
 	validationScheme := model.UTF8Validation
@@ -521,7 +521,7 @@ func (sp *scrapePool) sync(targets []*Target) {
 				mrc:                      mrc,
 				interval:                 interval,
 				timeout:                  timeout,
-				scrapeClassicHistograms:  scrapeClassicHistograms,
+				alwaysScrapeClassicHist:  alwaysScrapeClassicHist,
 				validationScheme:         validationScheme,
 			})
 			if err != nil {
@@ -883,7 +883,7 @@ type scrapeLoop struct {
 	labelLimits              *labelLimits
 	interval                 time.Duration
 	timeout                  time.Duration
-	scrapeClassicHistograms  bool
+	alwaysScrapeClassicHist  bool
 	validationScheme         model.ValidationScheme
 
 	// Feature flagged options.
@@ -1183,7 +1183,7 @@ func newScrapeLoop(ctx context.Context,
 	labelLimits *labelLimits,
 	interval time.Duration,
 	timeout time.Duration,
-	scrapeClassicHistograms bool,
+	alwaysScrapeClassicHist bool,
 	enableNativeHistogramIngestion bool,
 	enableCTZeroIngestion bool,
 	reportExtraMetrics bool,
@@ -1237,7 +1237,7 @@ func newScrapeLoop(ctx context.Context,
 		labelLimits:                    labelLimits,
 		interval:                       interval,
 		timeout:                        timeout,
-		scrapeClassicHistograms:        scrapeClassicHistograms,
+		alwaysScrapeClassicHist:        alwaysScrapeClassicHist,
 		enableNativeHistogramIngestion: enableNativeHistogramIngestion,
 		enableCTZeroIngestion:          enableCTZeroIngestion,
 		reportExtraMetrics:             reportExtraMetrics,
@@ -1537,7 +1537,7 @@ type appendErrors struct {
 }
 
 func (sl *scrapeLoop) append(app storage.Appender, b []byte, contentType string, ts time.Time) (total, added, seriesAdded int, err error) {
-	p, err := textparse.New(b, contentType, sl.scrapeClassicHistograms, sl.enableCTZeroIngestion, sl.symbolTable)
+	p, err := textparse.New(b, contentType, sl.alwaysScrapeClassicHist, sl.enableCTZeroIngestion, sl.symbolTable)
 	if err != nil {
 		sl.l.Debug(
 			"Invalid content type on scrape, using prometheus parser as fallback.",

scrape/scrape_test.go

@@ -1846,7 +1846,7 @@ func TestScrapeLoopAppendStalenessIfTrackTimestampStaleness(t *testing.T) {
 func TestScrapeLoopAppendExemplar(t *testing.T) {
 	tests := []struct {
 		title                           string
-		scrapeClassicHistograms         bool
+		alwaysScrapeClassicHist         bool
 		enableNativeHistogramsIngestion bool
 		scrapeText                      string
 		contentType                     string
@@ -2115,7 +2115,7 @@ metric: <
 >
 
 `,
-			scrapeClassicHistograms: true,
+			alwaysScrapeClassicHist: true,
 			contentType:             "application/vnd.google.protobuf",
 			floats: []floatSample{
 				{metric: labels.FromStrings("__name__", "test_histogram_count"), t: 1234568, f: 175},
@@ -2177,7 +2177,7 @@ metric: <
 			sl.reportSampleMutator = func(l labels.Labels) labels.Labels {
 				return mutateReportSampleLabels(l, discoveryLabels)
 			}
-			sl.scrapeClassicHistograms = test.scrapeClassicHistograms
+			sl.alwaysScrapeClassicHist = test.alwaysScrapeClassicHist
 
 			now := time.Now()