Make sure to apply escaping config

cmd/prometheus/main.go

@@ -432,6 +432,8 @@ func main() {
 	a.Flag("scrape.discovery-reload-interval", "Interval used by scrape manager to throttle target groups updates.").
 		Hidden().Default("5s").SetValue(&cfg.scrape.DiscoveryReloadInterval)
 
+	a.Flag("scrape.name-escaping-scheme", "method to escape legacy invalid names when sending to an old version of prometheus.  can be one of values (default), underscores, or dots").Default(model.DefaultNameEscapingScheme.String()).StringVar(&cfg.scrape.NameEscapingScheme)
+
 	a.Flag("enable-feature", "Comma separated feature names to enable. Valid options: agent, exemplar-storage, expand-external-labels, memory-snapshot-on-shutdown, promql-at-modifier, promql-negative-offset, promql-per-step-stats, promql-experimental-functions, remote-write-receiver (DEPRECATED), extra-scrape-metrics, new-service-discovery-manager, auto-gomaxprocs, no-default-scrape-port, native-histograms, otlp-write-receiver, utf8-names. See https://prometheus.io/docs/prometheus/latest/feature_flags/ for more details.").
 		Default("").StringsVar(&cfg.featureList)
 

scrape/manager.go

@@ -81,6 +81,8 @@ type Options struct {
 	// Option to enable the ingestion of the created timestamp as a synthetic zero sample.
 	// See: https://github.com/prometheus/proposals/blob/main/proposals/2023-06-13_created-timestamp.md
 	EnableCreatedTimestampZeroIngestion bool
+	// if UTF8 is not allowed, use this method 
+	NameEscapingScheme string
 
 	// Optional HTTP client options to use when scraping.
 	HTTPClientOptions []config_util.HTTPClientOption
@@ -156,6 +158,15 @@ func (m *Manager) reloader() {
 
 func (m *Manager) reload() {
 	m.mtxScrape.Lock()
+	defer m.mtxScrape.Unlock()
+	var err error
+	model.DefaultNameEscapingScheme, err = model.ToEscapingScheme(m.opts.NameEscapingScheme)
+	level.Info(m.logger).Log("msg", "ESCAPING SCHEME UPDATED", "scheme", m.opts.NameEscapingScheme)
+	if err != nil {
+		level.Error(m.logger).Log("msg", "error setting escaping scheme", "err", err)
+		return
+	}
+
 	var wg sync.WaitGroup
 	for setName, groups := range m.targetSets {
 		if _, ok := m.scrapePools[setName]; !ok {
@@ -182,7 +193,6 @@ func (m *Manager) reload() {
 		}(m.scrapePools[setName], groups)
 
 	}
-	m.mtxScrape.Unlock()
 	wg.Wait()
 }
 

scrape/scrape.go

@@ -672,7 +672,7 @@ func acceptHeader(sps []config.ScrapeProtocol, allowUTF8Names bool) string {
 	weight := len(config.ScrapeProtocolsHeaders) + 1
 	for _, sp := range sps {
 		val := config.ScrapeProtocolsHeaders[sp]
-		if (sp != config.PrometheusProto || sp == config.OpenMetricsText2_0_0 || sp == config.PrometheusText1_0_0) && allowUTF8Names {
+		if (sp == config.PrometheusProto || sp == config.OpenMetricsText2_0_0 || sp == config.PrometheusText1_0_0) && allowUTF8Names {
 			val += ";" + config.UTF8NamesHeader
 		}
 		val += fmt.Sprintf(";q=0.%d", weight)