restructure metrics implementation per review feedback

Signed-off-by: Rajat Jindal <[email protected]>

cmd/main.go

@@ -32,6 +32,7 @@ import (
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/healthz"
 	"sigs.k8s.io/controller-runtime/pkg/log/zap"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
 	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
 
 	spinv1 "github.com/spinkube/spin-operator/api/v1"
@@ -102,16 +103,18 @@ func main() {
 	}
 
 	if err = (&controller.SpinAppReconciler{
-		Client:   mgr.GetClient(),
-		Scheme:   mgr.GetScheme(),
-		Recorder: mgr.GetEventRecorderFor("spinapp-reconciler"),
+		Client:          mgr.GetClient(),
+		Scheme:          mgr.GetScheme(),
+		Recorder:        mgr.GetEventRecorderFor("spinapp-reconciler"),
+		MetricsRegistry: metrics.Registry,
 	}).SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "unable to create controller", "controller", "SpinApp")
 		os.Exit(1)
 	}
 	if err = (&controller.SpinAppExecutorReconciler{
-		Client: mgr.GetClient(),
-		Scheme: mgr.GetScheme(),
+		Client:          mgr.GetClient(),
+		Scheme:          mgr.GetScheme(),
+		MetricsRegistry: metrics.Registry,
 	}).SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "unable to create controller", "controller", "SpinAppExecutor")
 		os.Exit(1)

go.mod

@@ -6,6 +6,7 @@ toolchain go1.22.0
 
 require (
 	github.com/go-logr/logr v1.4.1
+	github.com/prometheus/client_golang v1.18.0
 	github.com/prometheus/common v0.48.0
 	github.com/stretchr/testify v1.8.4
 	k8s.io/api v0.29.2
@@ -41,7 +42,6 @@ require (
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/prometheus/client_golang v1.18.0 // indirect
 	github.com/prometheus/client_model v0.5.0 // indirect
 	github.com/prometheus/procfs v0.12.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect

internal/controller/spinapp_controller.go

@@ -30,6 +30,7 @@ import (
 	"k8s.io/client-go/tools/record"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
 
 	"github.com/prometheus/client_golang/prometheus"
 	spinv1 "github.com/spinkube/spin-operator/api/v1"
@@ -50,9 +51,11 @@ const (
 
 // SpinAppReconciler reconciles a SpinApp object
 type SpinAppReconciler struct {
-	Client   client.Client
-	Scheme   *runtime.Scheme
-	Recorder record.EventRecorder
+	Client          client.Client
+	Scheme          *runtime.Scheme
+	Recorder        record.EventRecorder
+	MetricsRegistry metrics.RegistererGatherer
+	metrics         *spinAppMetrics
 }
 
 //+kubebuilder:rbac:groups=core.spinoperator.dev,resources=spinapps,verbs=get;list;watch;create;update;patch;delete
@@ -63,6 +66,8 @@ type SpinAppReconciler struct {
 
 // SetupWithManager sets up the controller with the Manager.
 func (r *SpinAppReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	r.setupMetrics()
+
 	return ctrl.NewControllerManagedBy(mgr).
 		For(&spinv1.SpinApp{}).
 		// Owns allows watching dependency resources for any changes
@@ -92,7 +97,7 @@ func (r *SpinAppReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ct
 	}
 
 	// record spin_operator_spinapp_info metric
-	spinOperatorSpinAppInfo.With(prometheus.Labels{
+	r.metrics.infoGauge.With(prometheus.Labels{
 		"name":      spinApp.Name,
 		"namespace": spinApp.Namespace,
 		"executor":  spinApp.Spec.Executor,

internal/controller/spinapp_controller_test.go

@@ -22,6 +22,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/envtest"
 	"sigs.k8s.io/controller-runtime/pkg/log/zap"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
 	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
 )
 
@@ -103,9 +104,10 @@ func setupController(t *testing.T) (*envTestState, ctrl.Manager, *SpinAppReconci
 	require.NoError(t, err)
 
 	ctrlr := &SpinAppReconciler{
-		Client:   envTest.k8sClient,
-		Scheme:   envTest.scheme,
-		Recorder: mgr.GetEventRecorderFor("spinapp-reconciler"),
+		Client:          envTest.k8sClient,
+		Scheme:          envTest.scheme,
+		Recorder:        mgr.GetEventRecorderFor("spinapp-reconciler"),
+		MetricsRegistry: metrics.Registry,
 	}
 
 	require.NoError(t, ctrlr.SetupWithManager(mgr))

internal/controller/spinapp_executor_metrics.go

@@ -0,0 +1,36 @@
+package controller
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+type spinAppExecutorMetrics struct {
+	infoGauge *prometheus.GaugeVec
+}
+
+func newSpinAppExecutorMetrics() *spinAppExecutorMetrics {
+	return &spinAppExecutorMetrics{
+		infoGauge: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Name: "spin_operator_spinapp_executor_info",
+				Help: "info about spinapp executor labeled by name, namespace, create_deployment and runtime_class_name",
+			},
+			[]string{
+				"name",
+				"namespace",
+				"create_deployment",
+				"runtime_class_name",
+			},
+		),
+	}
+}
+
+func (m *spinAppExecutorMetrics) Register(registry metrics.RegistererGatherer) {
+	registry.MustRegister(m.infoGauge)
+}
+
+func (r *SpinAppExecutorReconciler) setupMetrics() {
+	r.metrics = newSpinAppExecutorMetrics()
+	r.metrics.Register(r.MetricsRegistry)
+}

internal/controller/spinapp_metrics.go

@@ -0,0 +1,35 @@
+package controller
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+type spinAppMetrics struct {
+	infoGauge *prometheus.GaugeVec
+}
+
+func newSpinAppMetrics() *spinAppMetrics {
+	return &spinAppMetrics{
+		infoGauge: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Name: "spin_operator_spinapp_info",
+				Help: "info about spinapp labeled by name, namespace, executor",
+			},
+			[]string{
+				"name",
+				"namespace",
+				"executor",
+			},
+		),
+	}
+}
+
+func (m *spinAppMetrics) Register(registry metrics.RegistererGatherer) {
+	registry.MustRegister(m.infoGauge)
+}
+
+func (r *SpinAppReconciler) setupMetrics() {
+	r.metrics = newSpinAppMetrics()
+	r.metrics.Register(r.MetricsRegistry)
+}

internal/controller/spinappexecutor_controller.go

@@ -25,6 +25,7 @@ import (
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
 
 	"github.com/prometheus/client_golang/prometheus"
 	spinv1 "github.com/spinkube/spin-operator/api/v1"
@@ -34,7 +35,9 @@ import (
 // SpinAppExecutorReconciler reconciles a SpinAppExecutor object
 type SpinAppExecutorReconciler struct {
 	client.Client
-	Scheme *runtime.Scheme
+	Scheme          *runtime.Scheme
+	MetricsRegistry metrics.RegistererGatherer
+	metrics         *spinAppExecutorMetrics
 }
 
 //+kubebuilder:rbac:groups=core.spinoperator.dev,resources=spinappexecutors,verbs=get;list;watch;create;update;patch;delete
@@ -43,6 +46,8 @@ type SpinAppExecutorReconciler struct {
 
 // SetupWithManager sets up the controller with the Manager.
 func (r *SpinAppExecutorReconciler) SetupWithManager(mgr ctrl.Manager) error {
+	r.setupMetrics()
+
 	return ctrl.NewControllerManagedBy(mgr).
 		For(&spinv1.SpinAppExecutor{}).
 		Complete(r)
@@ -84,7 +89,7 @@ func (r *SpinAppExecutorReconciler) Reconcile(ctx context.Context, req ctrl.Requ
 	}
 
 	// record spin_operator_spinapp_executor_info metric
-	spinOperatorSpinAppExecutorInfo.With(prometheus.Labels{
+	r.metrics.infoGauge.With(prometheus.Labels{
 		"name":               executor.Name,
 		"namespace":          executor.Namespace,
 		"create_deployment":  fmt.Sprintf("%t", executor.Spec.CreateDeployment),