Avoid nil point when config.Metrics is nil and expose all metrics if none are configured

cmd/ghalistener/app/app.go

@@ -69,8 +69,8 @@ func New(config config.Config) (*App, error) {
 			Repository:        ghConfig.Repository,
 			ServerAddr:        config.MetricsAddr,
 			ServerEndpoint:    config.MetricsEndpoint,
+			Metrics:           config.Metrics,
 			Logger:            app.logger.WithName("metrics exporter"),
-			Metrics:           *config.Metrics,
 		})
 	}
 

cmd/ghalistener/metrics/metrics.go

@@ -152,13 +152,148 @@ type ExporterConfig struct {
 	ServerAddr        string
 	ServerEndpoint    string
 	Logger            logr.Logger
-	Metrics           v1alpha1.MetricsConfig
+	Metrics           *v1alpha1.MetricsConfig
+}
+
+var defaultMetrics = v1alpha1.MetricsConfig{
+	Counters: map[string]*v1alpha1.CounterMetric{
+		MetricStartedJobsTotal: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyJobName,
+				labelKeyEventName,
+			},
+		},
+		MetricCompletedJobsTotal: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyJobName,
+				labelKeyEventName,
+				labelKeyJobResult,
+			},
+		},
+	},
+	Gauges: map[string]*v1alpha1.GaugeMetric{
+		MetricAssignedJobs: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+		MetricRunningJobs: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+		MetricRegisteredRunners: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+		MetricBusyRunners: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+		MetricMinRunners: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+		MetricMaxRunners: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+		MetricDesiredRunners: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+		MetricIdleRunners: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyRunnerScaleSetName,
+				labelKeyRunnerScaleSetNamespace,
+			},
+		},
+	},
+	Histograms: map[string]*v1alpha1.HistogramMetric{
+		MetricJobStartupDurationSeconds: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyJobName,
+				labelKeyEventName,
+			},
+			Buckets: defaultRuntimeBuckets,
+		},
+		MetricJobExecutionDurationSeconds: {
+			Labels: []string{
+				labelKeyEnterprise,
+				labelKeyOrganization,
+				labelKeyRepository,
+				labelKeyJobName,
+				labelKeyEventName,
+				labelKeyJobResult,
+			},
+			Buckets: defaultRuntimeBuckets,
+		},
+	},
+}
+
+func (e *ExporterConfig) defaults() {
+	if e.ServerAddr == "" {
+		e.ServerAddr = ":8080"
+	}
+	if e.ServerEndpoint == "" {
+		e.ServerEndpoint = "/metrics"
+	}
+	if e.Metrics == nil {
+		defaultMetrics := defaultMetrics
+		e.Metrics = &defaultMetrics
+	}
 }
 
 func NewExporter(config ExporterConfig) ServerExporter {
+	config.defaults()
 	reg := prometheus.NewRegistry()
 
-	metrics := installMetrics(config.Metrics, reg, config.Logger)
+	metrics := installMetrics(*config.Metrics, reg, config.Logger)
 
 	mux := http.NewServeMux()
 	mux.Handle(

cmd/ghalistener/metrics/metrics_test.go

@@ -7,6 +7,7 @@ import (
 	"github.com/go-logr/logr"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestInstallMetrics(t *testing.T) {
@@ -86,3 +87,179 @@ func TestInstallMetrics(t *testing.T) {
 	assert.Equal(t, duration.config.Labels, metricsConfig.Histograms[MetricJobStartupDurationSeconds].Labels)
 	assert.Equal(t, duration.config.Buckets, defaultRuntimeBuckets)
 }
+
+func TestNewExporter(t *testing.T) {
+	t.Run("with defaults metrics applied", func(t *testing.T) {
+		config := ExporterConfig{
+			ScaleSetName:      "test-scale-set",
+			ScaleSetNamespace: "test-namespace",
+			Enterprise:        "",
+			Organization:      "org",
+			Repository:        "repo",
+			ServerAddr:        ":6060",
+			ServerEndpoint:    "/metrics",
+			Logger:            logr.Discard(),
+			Metrics:           nil, // when metrics is nil, all default metrics should be registered
+		}
+
+		exporter, ok := NewExporter(config).(*exporter)
+		require.True(t, ok, "expected exporter to be of type *exporter")
+		require.NotNil(t, exporter)
+
+		reg := prometheus.NewRegistry()
+		wantMetrics := installMetrics(defaultMetrics, reg, config.Logger)
+
+		assert.Equal(t, len(wantMetrics.counters), len(exporter.counters))
+		for k, v := range wantMetrics.counters {
+			assert.Contains(t, exporter.counters, k)
+			assert.Equal(t, v.config, exporter.counters[k].config)
+		}
+
+		assert.Equal(t, len(wantMetrics.gauges), len(exporter.gauges))
+		for k, v := range wantMetrics.gauges {
+			assert.Contains(t, exporter.gauges, k)
+			assert.Equal(t, v.config, exporter.gauges[k].config)
+		}
+
+		assert.Equal(t, len(wantMetrics.histograms), len(exporter.histograms))
+		for k, v := range wantMetrics.histograms {
+			assert.Contains(t, exporter.histograms, k)
+			assert.Equal(t, v.config, exporter.histograms[k].config)
+		}
+
+		require.NotNil(t, exporter.srv)
+		assert.Equal(t, config.ServerAddr, exporter.srv.Addr)
+	})
+
+	t.Run("with default server URL", func(t *testing.T) {
+		config := ExporterConfig{
+			ScaleSetName:      "test-scale-set",
+			ScaleSetNamespace: "test-namespace",
+			Enterprise:        "",
+			Organization:      "org",
+			Repository:        "repo",
+			ServerAddr:        "", // empty ServerAddr should default to ":8080"
+			ServerEndpoint:    "",
+			Logger:            logr.Discard(),
+			Metrics:           nil, // when metrics is nil, all default metrics should be registered
+		}
+
+		exporter, ok := NewExporter(config).(*exporter)
+		require.True(t, ok, "expected exporter to be of type *exporter")
+		require.NotNil(t, exporter)
+
+		reg := prometheus.NewRegistry()
+		wantMetrics := installMetrics(defaultMetrics, reg, config.Logger)
+
+		assert.Equal(t, len(wantMetrics.counters), len(exporter.counters))
+		for k, v := range wantMetrics.counters {
+			assert.Contains(t, exporter.counters, k)
+			assert.Equal(t, v.config, exporter.counters[k].config)
+		}
+
+		assert.Equal(t, len(wantMetrics.gauges), len(exporter.gauges))
+		for k, v := range wantMetrics.gauges {
+			assert.Contains(t, exporter.gauges, k)
+			assert.Equal(t, v.config, exporter.gauges[k].config)
+		}
+
+		assert.Equal(t, len(wantMetrics.histograms), len(exporter.histograms))
+		for k, v := range wantMetrics.histograms {
+			assert.Contains(t, exporter.histograms, k)
+			assert.Equal(t, v.config, exporter.histograms[k].config)
+		}
+
+		require.NotNil(t, exporter.srv)
+		assert.Equal(t, exporter.srv.Addr, ":8080")
+	})
+
+	t.Run("with metrics configured", func(t *testing.T) {
+		metricsConfig := v1alpha1.MetricsConfig{
+			Counters: map[string]*v1alpha1.CounterMetric{
+				MetricStartedJobsTotal: {
+					Labels: []string{labelKeyRepository},
+				},
+			},
+			Gauges: map[string]*v1alpha1.GaugeMetric{
+				MetricAssignedJobs: {
+					Labels: []string{labelKeyRepository},
+				},
+			},
+			Histograms: map[string]*v1alpha1.HistogramMetric{
+				MetricJobExecutionDurationSeconds: {
+					Labels:  []string{labelKeyRepository},
+					Buckets: []float64{0.1, 1},
+				},
+			},
+		}
+
+		config := ExporterConfig{
+			ScaleSetName:      "test-scale-set",
+			ScaleSetNamespace: "test-namespace",
+			Enterprise:        "",
+			Organization:      "org",
+			Repository:        "repo",
+			ServerAddr:        ":6060",
+			ServerEndpoint:    "/metrics",
+			Logger:            logr.Discard(),
+			Metrics:           &metricsConfig,
+		}
+
+		exporter, ok := NewExporter(config).(*exporter)
+		require.True(t, ok, "expected exporter to be of type *exporter")
+		require.NotNil(t, exporter)
+
+		reg := prometheus.NewRegistry()
+		wantMetrics := installMetrics(metricsConfig, reg, config.Logger)
+
+		assert.Equal(t, len(wantMetrics.counters), len(exporter.counters))
+		for k, v := range wantMetrics.counters {
+			assert.Contains(t, exporter.counters, k)
+			assert.Equal(t, v.config, exporter.counters[k].config)
+		}
+
+		assert.Equal(t, len(wantMetrics.gauges), len(exporter.gauges))
+		for k, v := range wantMetrics.gauges {
+			assert.Contains(t, exporter.gauges, k)
+			assert.Equal(t, v.config, exporter.gauges[k].config)
+		}
+
+		assert.Equal(t, len(wantMetrics.histograms), len(exporter.histograms))
+		for k, v := range wantMetrics.histograms {
+			assert.Contains(t, exporter.histograms, k)
+			assert.Equal(t, v.config, exporter.histograms[k].config)
+		}
+
+		require.NotNil(t, exporter.srv)
+		assert.Equal(t, config.ServerAddr, exporter.srv.Addr)
+	})
+}
+
+func TestExporterConfigDefaults(t *testing.T) {
+	config := ExporterConfig{
+		ScaleSetName:      "test-scale-set",
+		ScaleSetNamespace: "test-namespace",
+		Enterprise:        "",
+		Organization:      "org",
+		Repository:        "repo",
+		ServerAddr:        "",
+		ServerEndpoint:    "",
+		Logger:            logr.Discard(),
+		Metrics:           nil, // when metrics is nil, all default metrics should be registered
+	}
+
+	config.defaults()
+	want := ExporterConfig{
+		ScaleSetName:      "test-scale-set",
+		ScaleSetNamespace: "test-namespace",
+		Enterprise:        "",
+		Organization:      "org",
+		Repository:        "repo",
+		ServerAddr:        ":8080",    // default server address
+		ServerEndpoint:    "/metrics", // default server endpoint
+		Logger:            logr.Discard(),
+		Metrics:           &defaultMetrics, // when metrics is nil, all default metrics should be registered
+	}
+
+	assert.Equal(t, want, config)
+}