Expose WriteMetadataIfNeeded() function

go_metrics.go

@@ -82,7 +82,7 @@ func writeGoMetrics(w io.Writer) {
 	}
 	phis := []float64{0, 0.25, 0.5, 0.75, 1}
 	quantiles := make([]float64, 0, len(phis))
-	writeMetadataIfNeeded(w, "go_gc_duration_seconds", "summary")
+	WriteMetadataIfNeeded(w, "go_gc_duration_seconds", "summary")
 	for i, q := range gcPauses.Quantiles(quantiles[:0], phis) {
 		fmt.Fprintf(w, `go_gc_duration_seconds{quantile="%g"} %g`+"\n", phis[i], q)
 	}
@@ -97,10 +97,10 @@ func writeGoMetrics(w io.Writer) {
 	WriteGaugeUint64(w, "go_threads", uint64(numThread))
 
 	// Export build details.
-	writeMetadataIfNeeded(w, "go_info", "gauge")
+	WriteMetadataIfNeeded(w, "go_info", "gauge")
 	fmt.Fprintf(w, "go_info{version=%q} 1\n", runtime.Version())
 
-	writeMetadataIfNeeded(w, "go_info_ext", "gauge")
+	WriteMetadataIfNeeded(w, "go_info_ext", "gauge")
 	fmt.Fprintf(w, "go_info_ext{compiler=%q, GOARCH=%q, GOOS=%q, GOROOT=%q} 1\n",
 		runtime.Compiler, runtime.GOARCH, runtime.GOOS, runtime.GOROOT())
 }
@@ -165,7 +165,7 @@ func writeRuntimeHistogramMetric(w io.Writer, name string, h *runtimemetrics.Flo
 
 	totalCount := uint64(0)
 	iNext := 0.0
-	writeMetadataIfNeeded(w, name, "histogram")
+	WriteMetadataIfNeeded(w, name, "histogram")
 	for i, count := range counts {
 		totalCount += count
 		if float64(i) >= iNext {

metrics.go

@@ -290,16 +290,19 @@ func WriteCounterFloat64(w io.Writer, name string, value float64) {
 }
 
 func writeMetricUint64(w io.Writer, metricName, metricType string, value uint64) {
-	writeMetadataIfNeeded(w, metricName, metricType)
+	WriteMetadataIfNeeded(w, metricName, metricType)
 	fmt.Fprintf(w, "%s %d\n", metricName, value)
 }
 
 func writeMetricFloat64(w io.Writer, metricName, metricType string, value float64) {
-	writeMetadataIfNeeded(w, metricName, metricType)
+	WriteMetadataIfNeeded(w, metricName, metricType)
 	fmt.Fprintf(w, "%s %g\n", metricName, value)
 }
 
-func writeMetadataIfNeeded(w io.Writer, metricName, metricType string) {
+// WriteMetadataIfNeeded writes HELP and TYPE metadata for the given metricName and metricType if this is globally enabled via ExposeMetadata().
+//
+// If the metadata exposition isn't enabled, then this function is no-op.
+func WriteMetadataIfNeeded(w io.Writer, metricName, metricType string) {
 	if !isMetadataEnabled() {
 		return
 	}

set.go

@@ -53,7 +53,7 @@ func (s *Set) WritePrometheus(w io.Writer) {
 		if metricFamily != prevMetricFamily {
 			// write meta info only once per metric family
 			metricType := nm.metric.metricType()
-			writeMetadataIfNeeded(&bb, nm.name, metricType)
+			WriteMetadataIfNeeded(&bb, nm.name, metricType)
 			prevMetricFamily = metricFamily
 		}
 		// Call marshalTo without the global lock, since certain metric types such as Gauge