Move metrics package one level up

Author: timebertt

cmd/sharder/app/app.go

@@ -32,6 +32,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/controller"
+	shardingmetrics "github.com/timebertt/kubernetes-controller-sharding/pkg/metrics"
 	healthzutils "github.com/timebertt/kubernetes-controller-sharding/pkg/utils/healthz"
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/webhook"
 )
@@ -104,6 +105,11 @@ func run(ctx context.Context, log logr.Logger, opts *options) error {
 		return fmt.Errorf("failed adding webhooks to manager: %w", err)
 	}
 
+	log.Info("Adding metrics to manager")
+	if err = shardingmetrics.AddToManager(mgr); err != nil {
+		return fmt.Errorf("failed adding metrics to manager: %w", err)
+	}
+
 	log.Info("Starting manager")
 	return mgr.Start(ctx)
 }

pkg/controller/sharder/reconciler.go

@@ -38,10 +38,10 @@ import (
 
 	configv1alpha1 "github.com/timebertt/kubernetes-controller-sharding/pkg/apis/config/v1alpha1"
 	shardingv1alpha1 "github.com/timebertt/kubernetes-controller-sharding/pkg/apis/sharding/v1alpha1"
+	shardingmetrics "github.com/timebertt/kubernetes-controller-sharding/pkg/metrics"
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/consistenthash"
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/key"
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/leases"
-	shardingmetrics "github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/metrics"
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/ring"
 	utilclient "github.com/timebertt/kubernetes-controller-sharding/pkg/utils/client"
 	utilerrors "github.com/timebertt/kubernetes-controller-sharding/pkg/utils/errors"

pkg/metrics/add.go

@@ -0,0 +1,43 @@
+/*
+Copyright 2025 Tim Ebert.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package metrics
+
+import (
+	"fmt"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/manager"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+const Namespace = "controller_sharding"
+
+// AddToManager adds all metrics exporters for sharding objects to the manager.
+func AddToManager(mgr manager.Manager) error {
+	for _, collector := range []prometheus.Collector{
+		AssignmentsTotal,
+		MovementsTotal,
+		DrainsTotal,
+		RingCalculationsTotal,
+	} {
+		if err := metrics.Registry.Register(collector); err != nil {
+			return fmt.Errorf("failed to add sharding operations metrics: %w", err)
+		}
+	}
+
+	return nil
+}

pkg/sharding/metrics/metrics.go renamed to pkg/metrics/operations.go

@@ -18,12 +18,8 @@ package metrics
 
 import (
 	"github.com/prometheus/client_golang/prometheus"
-
-	"sigs.k8s.io/controller-runtime/pkg/metrics"
 )
 
-const Namespace = "controller_sharding"
-
 var (
 	// AssignmentsTotal is a prometheus counter metric which holds the total number of shard assignments by the sharder
 	// webhook per ControllerRing and GroupResource.
@@ -61,12 +57,3 @@ var (
 		Help:      "Total number of hash ring calculations per ControllerRing",
 	}, []string{"controllerring"})
 )
-
-func init() {
-	metrics.Registry.MustRegister(
-		AssignmentsTotal,
-		MovementsTotal,
-		DrainsTotal,
-		RingCalculationsTotal,
-	)
-}

pkg/sharding/ring/ring.go

@@ -22,9 +22,9 @@ import (
 	coordinationv1 "k8s.io/api/coordination/v1"
 
 	shardingv1alpha1 "github.com/timebertt/kubernetes-controller-sharding/pkg/apis/sharding/v1alpha1"
+	shardingmetrics "github.com/timebertt/kubernetes-controller-sharding/pkg/metrics"
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/consistenthash"
 	"github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/leases"
-	shardingmetrics "github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/metrics"
 )
 
 // FromLeases creates a ring from the given membership information (shard leases). It transforms shard leases into a

pkg/webhook/sharder/metrics.go

@@ -19,7 +19,7 @@ package sharder
 import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
-	shardingmetrics "github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/metrics"
+	shardingmetrics "github.com/timebertt/kubernetes-controller-sharding/pkg/metrics"
 )
 
 type Metrics interface {