add example on initializing workspaces

Signed-off-by: Karol Szwaj <[email protected]>

On-behalf-of: @SAP [email protected]

Author: cnvergence

examples/apiexport/main.go

@@ -19,7 +19,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"net/http"
 	"os"
 
 	"github.com/spf13/pflag"
@@ -139,9 +138,3 @@ func main() {
 		os.Exit(1)
 	}
 }
-
-type RoundTripperFunc func(*http.Request) (*http.Response, error)
-
-func (f RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
-	return f(r)
-}

examples/initializingworkspaces/main.go

@@ -0,0 +1,170 @@
+/*
+Copyright 2025 The KCP Authors.
+
+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 main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"slices"
+
+	"github.com/spf13/pflag"
+
+	apisv1alpha1 "github.com/kcp-dev/kcp/sdk/apis/apis/v1alpha1"
+
+	corev1alpha1 "github.com/kcp-dev/kcp/sdk/apis/core/v1alpha1"
+	"github.com/kcp-dev/kcp/sdk/apis/tenancy/initialization"
+	tenancyv1alpha1 "github.com/kcp-dev/kcp/sdk/apis/tenancy/v1alpha1"
+	"github.com/kcp-dev/multicluster-provider/initializingworkspaces"
+	ctrlclient "sigs.k8s.io/controller-runtime/pkg/client"
+	mcbuilder "sigs.k8s.io/multicluster-runtime/pkg/builder"
+	mcmanager "sigs.k8s.io/multicluster-runtime/pkg/manager"
+	mcreconcile "sigs.k8s.io/multicluster-runtime/pkg/reconcile"
+
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/client-go/kubernetes/scheme"
+	"k8s.io/client-go/rest"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/log/zap"
+	"sigs.k8s.io/controller-runtime/pkg/manager"
+	"sigs.k8s.io/controller-runtime/pkg/manager/signals"
+	"sigs.k8s.io/controller-runtime/pkg/reconcile"
+)
+
+func init() {
+	runtime.Must(corev1alpha1.AddToScheme(scheme.Scheme))
+	runtime.Must(tenancyv1alpha1.AddToScheme(scheme.Scheme))
+	runtime.Must(apisv1alpha1.AddToScheme(scheme.Scheme))
+}
+
+func main() {
+	initializerName := "initializer:example"
+	log.SetLogger(zap.New(zap.UseDevMode(true)))
+
+	ctx := signals.SetupSignalHandler()
+	entryLog := log.Log.WithName("entrypoint")
+
+	var (
+		server   string
+		provider *initializingworkspaces.Provider
+	)
+
+	pflag.StringVar(&server, "server", "", "Override for kubeconfig server URL")
+	pflag.Parse()
+
+	cfg := ctrl.GetConfigOrDie()
+	cfg = rest.CopyConfig(cfg)
+
+	if server != "" {
+		cfg.Host = server
+	}
+
+	// Setup a Manager, note that this not yet engages clusters, only makes them available.
+	entryLog.Info("Setting up manager")
+	opts := manager.Options{}
+
+	var err error
+	provider, err = initializingworkspaces.New(cfg, initializingworkspaces.Options{})
+	if err != nil {
+		entryLog.Error(err, "unable to construct cluster provider")
+		os.Exit(1)
+	}
+
+	mgr, err := mcmanager.New(cfg, provider, opts)
+	if err != nil {
+		entryLog.Error(err, "unable to set up overall controller manager")
+		os.Exit(1)
+	}
+
+	if err := mcbuilder.ControllerManagedBy(mgr).
+		Named("kcp-initializer-configmap-controller").
+		For(&corev1.ConfigMap{}).
+		Complete(mcreconcile.Func(
+			func(ctx context.Context, req mcreconcile.Request) (ctrl.Result, error) {
+				log := log.FromContext(ctx).WithValues("cluster", req.ClusterName)
+
+				cl, err := mgr.GetCluster(ctx, req.ClusterName)
+				if err != nil {
+					return reconcile.Result{}, fmt.Errorf("failed to get cluster: %w", err)
+				}
+				client := cl.GetClient()
+
+				lc := &corev1alpha1.LogicalCluster{}
+				if err := client.Get(ctx, req.NamespacedName, lc); err != nil {
+					return reconcile.Result{}, err
+				}
+
+				// check if your initializer is still set on the logicalcluster
+				if slices.Contains(lc.Status.Initializers, corev1alpha1.LogicalClusterInitializer(initializerName)) {
+
+					log.Info("Starting to initialize cluster")
+
+					s := &corev1.ConfigMap{
+						ObjectMeta: ctrl.ObjectMeta{
+							Name:      "kcp-initializer-cm",
+							Namespace: req.NamespacedName.Namespace,
+						},
+						Data: map[string]string{
+							"test-data": "example-value",
+						},
+					}
+					if err := client.Create(ctx, s); err != nil {
+						return reconcile.Result{}, fmt.Errorf("failed to create configmap: %w", err)
+					}
+					log.Info("Created ConfigMap", "name", s.Name, "uuid", s.UID)
+					// Remove the initializer from the logical cluster status
+					// so that it won't be processed again.
+
+					initializerName := corev1alpha1.LogicalClusterInitializer(initializerName)
+					if !slices.Contains(lc.Status.Initializers, initializerName) {
+						log.Info("Initializer already absent, skipping patch")
+						return reconcile.Result{}, nil
+					}
+					log.Info("Reconciling ConfigMap", "name", s.Name, "uuid", s.UID)
+
+					patch := ctrlclient.MergeFrom(lc.DeepCopy())
+					lc.Status.Initializers = initialization.EnsureInitializerAbsent(initializerName, lc.Status.Initializers)
+					if err := client.Status().Patch(ctx, lc, patch); err != nil {
+						return reconcile.Result{}, err
+					}
+					log.Info("Removed initializer from LogicalCluster status", "name", lc.Name, "uuid", lc.UID)
+				}
+				return reconcile.Result{}, nil
+			},
+		)); err != nil {
+		entryLog.Error(err, "failed to build controller")
+		os.Exit(1)
+	}
+
+	if provider != nil {
+		entryLog.Info("Starting provider")
+		go func() {
+			if err := provider.Run(ctx, mgr); err != nil {
+				entryLog.Error(err, "unable to run provider")
+				os.Exit(1)
+			}
+		}()
+	}
+
+	entryLog.Info("Starting manager")
+	if err := mgr.Start(ctx); err != nil {
+		entryLog.Error(err, "unable to run manager")
+		os.Exit(1)
+	}
+}