Rethink struct for newly added metrics, adapt and add tests

Signed-off-by: Arianna Vespri <arianna.vespri@yahoo.it>

prometheus/collectors/go_collector_latest.go

@@ -88,6 +88,10 @@ func WithGoCollectorMemStatsMetricsDisabled() func(options *internal.GoCollector
 	}
 }
 
+// WithGoCollectorRuntimeEnvVarsMetricsDisabled disables the following default metrics:
+// go_gogc_percent
+// go_gomemlimit
+// go_gomaxprocs
 func WithGoCollectorRuntimeEnvVarsMetricsDisabled() func(options *internal.GoCollectorOptions) {
 	return func(o *internal.GoCollectorOptions) {
 		o.DisableRuntimeEnvVarsMetrics = true

prometheus/collectors/go_collector_latest_test.go

@@ -54,10 +54,11 @@ func TestGoCollectorMarshalling(t *testing.T) {
 	}
 }
 
-func TestWithGoCollectorMemStatsMetricsDisabled(t *testing.T) {
+func TestWithBaseMetricsOnly(t *testing.T) {
 	reg := prometheus.NewRegistry()
 	reg.MustRegister(NewGoCollector(
 		WithGoCollectorMemStatsMetricsDisabled(),
+		WithGoCollectorRuntimeEnvVarsMetricsDisabled(),
 	))
 	result, err := reg.Gather()
 	if err != nil {
@@ -116,6 +117,7 @@ func TestGoCollectorAllowList(t *testing.T) {
 			reg.MustRegister(NewGoCollector(
 				WithGoCollectorMemStatsMetricsDisabled(),
 				WithGoCollectorRuntimeMetrics(test.rules...),
+				WithGoCollectorRuntimeEnvVarsMetricsDisabled(),
 			))
 			result, err := reg.Gather()
 			if err != nil {
@@ -170,6 +172,7 @@ func TestGoCollectorDenyList(t *testing.T) {
 			reg.MustRegister(NewGoCollector(
 				WithGoCollectorMemStatsMetricsDisabled(),
 				WithoutGoCollectorRuntimeMetrics(test.matchers...),
+				WithGoCollectorRuntimeEnvVarsMetricsDisabled(),
 			))
 			result, err := reg.Gather()
 			if err != nil {
@@ -213,6 +216,7 @@ func ExampleGoCollector_WithAdvancedGoMetrics() {
 				},
 			),
 			WithoutGoCollectorRuntimeMetrics(regexp.MustCompile("^/gc/.*")),
+			WithGoCollectorRuntimeEnvVarsMetricsDisabled(),
 		))
 
 	http.Handle("/metrics", promhttp.HandlerFor(reg, promhttp.HandlerOpts{}))

prometheus/go_collector.go

@@ -289,8 +289,7 @@ func goRuntimeEnvVarsMetrics() runtimeEnvVarsMetrics {
 				"Value of GOGC (percentage).",
 				nil, nil,
 			),
-			eval:    float64(readRunMetrSample("/gc/gogc:percent")[0].Value.Uint64()),
+			origMetricName: "/gc/gogc:percent",
-			valType: GaugeValue,
 		},
 		{
 			desc: NewDesc(
@@ -298,8 +297,7 @@ func goRuntimeEnvVarsMetrics() runtimeEnvVarsMetrics {
 				"Value of GOMEMLIMIT (bytes).",
 				nil, nil,
 			),
-			eval:    float64(readRunMetrSample("/gc/gomemlimit:bytes")[0].Value.Uint64()),
+			origMetricName: "/gc/gomemlimit:bytes",
-			valType: GaugeValue,
 		},
 		{
 			desc: NewDesc(
@@ -307,21 +305,19 @@ func goRuntimeEnvVarsMetrics() runtimeEnvVarsMetrics {
 				"Value of GOMAXPROCS, i.e number of usable threads.",
 				nil, nil,
 			),
-			eval:    float64(runtime.NumCPU()),
+			origMetricName: "/sched/gomaxprocs:threads",
-			valType: GaugeValue,
 		},
 	}
 }
 
-type runtimeEnvVarsMetrics []struct { // how to call this struct?
+type runtimeEnvVarsMetrics []struct { // I couldn't come up with a better name. Any suggestions?
-	desc    *Desc
+	desc           *Desc
-	eval    float64
+	origMetricName string
-	valType ValueType
 }
 
-func readRunMetrSample(metricName string) []runmetr.Sample {
+func readRunMetrSampleBuf(metricName string) []runmetr.Sample {
-	sample := make([]runmetr.Sample, 1)
+	sampleBuf := make([]runmetr.Sample, 1)
-	sample[0].Name = metricName
+	sampleBuf[0].Name = metricName
-	runmetr.Read(sample)
+	runmetr.Read(sampleBuf)
-	return sample
+	return sampleBuf
 }

prometheus/go_collector_latest.go

@@ -81,7 +81,7 @@ var rmNamesForMemStatsMetrics = []string{
 	goMemoryClassesOtherBytes,
 }
 
-var rmNamesForEnvVarsMetrics = []string{ // how to call them???
+var rmNamesForEnvVarsMetrics = []string{ // how to name this var???
 	goGCGogcPercent,
 	goGCMemLimit,
 	goSchedMaxProcs,
@@ -389,6 +389,12 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 			ch <- MustNewConstMetric(i.desc, i.valType, i.eval(&ms))
 		}
 	}
+
+	if c.rmEnvVarMetricsEnabled {
+		for _, v := range c.rmEnvVarMetrics {
+			ch <- MustNewConstMetric(v.desc, GaugeValue, float64(readRunMetrSampleBuf(v.origMetricName)[0].Value.Uint64()))
+		}
+	}
 }
 
 // unwrapScalarRMValue unwraps a runtime/metrics value that is assumed

prometheus/go_collector_latest_test.go

@@ -74,6 +74,13 @@ func addExpectedRuntimeMetrics(metrics map[string]struct{}) map[string]struct{}
 	return metrics
 }
 
+func addExpectedEnvVarsMetrics(metrics map[string]struct{}) map[string]struct{} {
+	for _, m := range goRuntimeEnvVarsMetrics() {
+		metrics[m.desc.fqName] = struct{}{}
+	}
+	return metrics
+}
+
 func TestGoCollector_ExposedMetrics(t *testing.T) {
 	for _, tcase := range []struct {
 		opts              internal.GoCollectorOptions
@@ -81,18 +88,27 @@ func TestGoCollector_ExposedMetrics(t *testing.T) {
 	}{
 		{
 			opts: internal.GoCollectorOptions{
-				DisableMemStatsLikeMetrics: true,
+				DisableMemStatsLikeMetrics:   true,
+				DisableRuntimeEnvVarsMetrics: true,
 			},
 			expectedFQNameSet: expectedBaseMetrics(),
 		},
 		{
-			// Default, only MemStats.
+			// Default, only Memstats and RuntimeEnvVars.
+			expectedFQNameSet: addExpectedEnvVarsMetrics(addExpectedRuntimeMemStats(expectedBaseMetrics())),
+		},
+		{
+			// Only MemStats.
+			opts: internal.GoCollectorOptions{
+				DisableRuntimeEnvVarsMetrics: true,
+			},
 			expectedFQNameSet: addExpectedRuntimeMemStats(expectedBaseMetrics()),
 		},
 		{
-			// Get all runtime/metrics without MemStats.
+			// Get all runtime/metrics without MemStats nor RuntimeEnvVars.
 			opts: internal.GoCollectorOptions{
-				DisableMemStatsLikeMetrics: true,
+				DisableMemStatsLikeMetrics:   true,
+				DisableRuntimeEnvVarsMetrics: true,
 				RuntimeMetricRules: []internal.GoCollectorRule{
 					{Matcher: regexp.MustCompile("/.*")},
 				},
@@ -100,13 +116,20 @@ func TestGoCollector_ExposedMetrics(t *testing.T) {
 			expectedFQNameSet: addExpectedRuntimeMetrics(expectedBaseMetrics()),
 		},
 		{
-			// Get all runtime/metrics and MemStats.
+			// Get all runtime/metrics, MemStats and RuntimeEnvVars.
 			opts: internal.GoCollectorOptions{
 				RuntimeMetricRules: []internal.GoCollectorRule{
 					{Matcher: regexp.MustCompile("/.*")},
 				},
 			},
-			expectedFQNameSet: addExpectedRuntimeMemStats(addExpectedRuntimeMetrics(expectedBaseMetrics())),
+			expectedFQNameSet: addExpectedEnvVarsMetrics(addExpectedRuntimeMemStats(addExpectedRuntimeMetrics(expectedBaseMetrics()))),
+		},
+		{
+			// Only RuntimeEnvVars.
+			opts: internal.GoCollectorOptions{
+				DisableMemStatsLikeMetrics: true,
+			},
+			expectedFQNameSet: addExpectedEnvVarsMetrics(expectedBaseMetrics()),
 		},
 	} {
 		if ok := t.Run("", func(t *testing.T) {
@@ -229,6 +252,7 @@ func collectGoMetrics(t *testing.T, opts internal.GoCollectorOptions) []Metric {
 		o.DisableMemStatsLikeMetrics = opts.DisableMemStatsLikeMetrics
 		o.RuntimeMetricSumForHist = opts.RuntimeMetricSumForHist
 		o.RuntimeMetricRules = opts.RuntimeMetricRules
+		o.DisableRuntimeEnvVarsMetrics = opts.DisableRuntimeEnvVarsMetrics
 	}).(*goCollector)
 
 	// Collect all metrics.