WIP: Add registry metrics collectors

controllers/hcpvaultsecretsapp_controller.go

@@ -32,6 +32,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/controller"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 	"sigs.k8s.io/controller-runtime/pkg/log"
+	ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
 
 	"github.com/hashicorp/vault-secrets-operator/credentials"
 	"github.com/hashicorp/vault-secrets-operator/credentials/hcp"
@@ -302,9 +303,16 @@ func (r *HCPVaultSecretsAppReconciler) updateStatus(ctx context.Context, o *secr
 // SetupWithManager sets up the controller with the Manager.
 func (r *HCPVaultSecretsAppReconciler) SetupWithManager(mgr ctrl.Manager, opts controller.Options) error {
 	r.referenceCache = newResourceReferenceCache()
+	ctrlmetrics.Registry.MustRegister(
+		newResourceReferenceCacheCollector(r.referenceCache, "hcpvaultsecretsapp"),
+	)
+
 	if r.BackOffRegistry == nil {
 		r.BackOffRegistry = NewBackOffRegistry()
 	}
+	ctrlmetrics.Registry.MustRegister(
+		newBackoffRegistryCacheCollector(r.BackOffRegistry, "hcpvaultsecretsapp"),
+	)
 
 	return ctrl.NewControllerManagedBy(mgr).
 		For(&secretsv1beta1.HCPVaultSecretsApp{}).

controllers/registry.go

@@ -8,7 +8,10 @@ import (
 	"time"
 
 	"github.com/cenkalti/backoff/v4"
+	"github.com/prometheus/client_golang/prometheus"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+
+	"github.com/hashicorp/vault-secrets-operator/internal/metrics"
 )
 
 type ResourceKind int
@@ -49,6 +52,7 @@ type ResourceReferenceCache interface {
 	Get(ResourceKind, client.ObjectKey) []client.ObjectKey
 	Remove(ResourceKind, client.ObjectKey) bool
 	Prune(ResourceKind, client.ObjectKey) int
+	Len() int
 }
 
 var _ ResourceReferenceCache = (*resourceReferenceCache)(nil)
@@ -80,6 +84,20 @@ type resourceReferenceCache struct {
 	mu sync.RWMutex
 }
 
+func (c *resourceReferenceCache) Len() int {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	var l int
+	for _, scope := range c.m {
+		for _, refs := range scope {
+			l += len(refs)
+		}
+	}
+
+	return l
+}
+
 // Set references of kind for referrer.
 func (c *resourceReferenceCache) Set(kind ResourceKind, referrer client.ObjectKey, references ...client.ObjectKey) {
 	c.mu.Lock()
@@ -274,6 +292,13 @@ func (r *BackOffRegistry) Get(objKey client.ObjectKey) (*BackOff, bool) {
 	return entry, !ok
 }
 
+func (r *BackOffRegistry) Len() int {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	return len(r.m)
+}
+
 // BackOff is a wrapper around backoff.BackOff that does not implement
 // BackOff.Reset, since elements in BackOffRegistry are meant to be ephemeral.
 type BackOff struct {
@@ -304,3 +329,57 @@ func NewBackOffRegistry(opts ...backoff.ExponentialBackOffOpts) *BackOffRegistry
 		opts: opts,
 	}
 }
+
+// registryCacheCollector provides a prometheus.Collector for ClientCache metrics.
+type registryCacheCollector struct {
+	cache   ResourceReferenceCache
+	size    float64
+	lenDesc *prometheus.Desc
+}
+
+func (c registryCacheCollector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- c.lenDesc
+}
+
+func (c registryCacheCollector) Collect(ch chan<- prometheus.Metric) {
+	ch <- prometheus.MustNewConstMetric(c.lenDesc, prometheus.GaugeValue, float64(c.cache.Len()))
+}
+
+func newResourceReferenceCacheCollector(cache ResourceReferenceCache, name string) prometheus.Collector {
+	metricsFQNClientCacheLength := prometheus.BuildFQName(
+		metrics.Namespace, "rsc_ref_cache", metrics.NameLength)
+	return &registryCacheCollector{
+		cache: cache,
+		lenDesc: prometheus.NewDesc(
+			metricsFQNClientCacheLength,
+			"Number of object references in the cache.",
+			nil, map[string]string{"name": name}),
+	}
+}
+
+// backoffRegistryCacheCollector
+type backoffRegistryCacheCollector struct {
+	cache   *BackOffRegistry
+	size    float64
+	lenDesc *prometheus.Desc
+}
+
+func (c backoffRegistryCacheCollector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- c.lenDesc
+}
+
+func (c backoffRegistryCacheCollector) Collect(ch chan<- prometheus.Metric) {
+	ch <- prometheus.MustNewConstMetric(c.lenDesc, prometheus.GaugeValue, float64(c.cache.Len()))
+}
+
+func newBackoffRegistryCacheCollector(cache *BackOffRegistry, name string) prometheus.Collector {
+	metricsFQNClientCacheLength := prometheus.BuildFQName(
+		metrics.Namespace, "backoff_registry_cache", metrics.NameLength)
+	return &backoffRegistryCacheCollector{
+		cache: cache,
+		lenDesc: prometheus.NewDesc(
+			metricsFQNClientCacheLength,
+			"Number of backoff objects in the cache.",
+			nil, map[string]string{"name": name}),
+	}
+}

controllers/registry_test.go

@@ -60,7 +60,7 @@ func Test_resourceReferenceCache(t *testing.T) {
 				{
 					action:     0,
 					referrer:   referrer1,
-					references: []client.ObjectKey{reference1},
+					references: []client.ObjectKey{reference1, reference1, reference1},
 				},
 			},
 			m: refCacheMap{

controllers/vaultauth_controller.go

@@ -21,6 +21,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 	"sigs.k8s.io/controller-runtime/pkg/log"
+	ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 
 	secretsv1beta1 "github.com/hashicorp/vault-secrets-operator/api/v1beta1"
@@ -241,6 +242,10 @@ func (r *VaultAuthReconciler) handleFinalizer(ctx context.Context, o *secretsv1b
 // SetupWithManager sets up the controller with the Manager.
 func (r *VaultAuthReconciler) SetupWithManager(mgr ctrl.Manager) error {
 	r.referenceCache = newResourceReferenceCache()
+	ctrlmetrics.Registry.MustRegister(
+		newResourceReferenceCacheCollector(r.referenceCache, "vaultauth"),
+	)
+
 	return ctrl.NewControllerManagedBy(mgr).
 		For(&secretsv1beta1.VaultAuth{}).
 		Watches(

controllers/vaultdynamicsecret_controller.go

@@ -22,9 +22,10 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/client-go/tools/record"
+	"sigs.k8s.io/controller-runtime/pkg/builder"
+	ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
 
 	ctrl "sigs.k8s.io/controller-runtime"
-	"sigs.k8s.io/controller-runtime/pkg/builder"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
@@ -596,9 +597,15 @@ func (r *VaultDynamicSecretReconciler) renewLease(
 // SetupWithManager sets up the controller with the Manager.
 func (r *VaultDynamicSecretReconciler) SetupWithManager(mgr ctrl.Manager, opts controller.Options) error {
 	r.referenceCache = newResourceReferenceCache()
+	ctrlmetrics.Registry.MustRegister(
+		newResourceReferenceCacheCollector(r.referenceCache, "vaultdynamicsecret"),
+	)
 	if r.BackOffRegistry == nil {
 		r.BackOffRegistry = NewBackOffRegistry()
 	}
+	ctrlmetrics.Registry.MustRegister(
+		newBackoffRegistryCacheCollector(r.BackOffRegistry, "vaultdynamicsecret"),
+	)
 
 	r.ClientFactory.RegisterClientCallbackHandler(
 		vault.ClientCallbackHandler{

controllers/vaultpkisecret_controller.go

@@ -25,6 +25,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/controller"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 	"sigs.k8s.io/controller-runtime/pkg/log"
+	ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
 
 	secretsv1beta1 "github.com/hashicorp/vault-secrets-operator/api/v1beta1"
 	"github.com/hashicorp/vault-secrets-operator/consts"
@@ -347,8 +348,15 @@ func (r *VaultPKISecretReconciler) handleDeletion(ctx context.Context, o *secret
 
 func (r *VaultPKISecretReconciler) SetupWithManager(mgr ctrl.Manager, opts controller.Options) error {
 	r.referenceCache = newResourceReferenceCache()
+	ctrlmetrics.Registry.MustRegister(
+		newResourceReferenceCacheCollector(r.referenceCache, "vaultpkisecret"),
+	)
+
 	if r.BackOffRegistry == nil {
 		r.BackOffRegistry = NewBackOffRegistry()
+		ctrlmetrics.Registry.MustRegister(
+			newBackoffRegistryCacheCollector(r.BackOffRegistry, "vaultpkisecret"),
+		)
 	}
 	return ctrl.NewControllerManagedBy(mgr).
 		For(&secretsv1beta1.VaultPKISecret{}).

controllers/vaultstaticsecret_controller.go

@@ -24,6 +24,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 	"sigs.k8s.io/controller-runtime/pkg/event"
 	"sigs.k8s.io/controller-runtime/pkg/log"
+	ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
 	"sigs.k8s.io/controller-runtime/pkg/source"
 
 	"github.com/cenkalti/backoff/v4"
@@ -500,9 +501,17 @@ func (r *VaultStaticSecretReconciler) streamStaticSecretEvents(ctx context.Conte
 
 func (r *VaultStaticSecretReconciler) SetupWithManager(mgr ctrl.Manager, opts controller.Options) error {
 	r.referenceCache = newResourceReferenceCache()
+	ctrlmetrics.Registry.MustRegister(
+		newResourceReferenceCacheCollector(r.referenceCache, "vaultstaticsecret"),
+	)
+
 	if r.BackOffRegistry == nil {
 		r.BackOffRegistry = NewBackOffRegistry()
 	}
+	ctrlmetrics.Registry.MustRegister(
+		newBackoffRegistryCacheCollector(r.BackOffRegistry, "vaultstaticsecret"),
+	)
+
 	r.SourceCh = make(chan event.GenericEvent)
 	r.eventWatcherRegistry = newEventWatcherRegistry()