Add simple reflector-like program for test

webhosting-operator/main.go

@@ -0,0 +1,115 @@
+/*
+Copyright 2023 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 main
+
+import (
+	"context"
+	"log"
+
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/json"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/client-go/dynamic"
+	"sigs.k8s.io/controller-runtime/pkg/client/config"
+	"sigs.k8s.io/controller-runtime/pkg/manager/signals"
+
+	webhostingv1alpha1 "github.com/timebertt/kubernetes-controller-sharding/webhosting-operator/pkg/apis/webhosting/v1alpha1"
+)
+
+func main() {
+	ctx := signals.SetupSignalHandler()
+	cfg := config.GetConfigOrDie()
+
+	d := dynamic.NewForConfigOrDie(cfg)
+
+	lastResourceVersion := ""
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
+
+		log.Printf("Starting watch with resourceVersion %q", lastResourceVersion)
+		w, err := d.Resource(webhostingv1alpha1.SchemeGroupVersion.WithResource("websites")).Watch(ctx, metav1.ListOptions{
+			AllowWatchBookmarks: true,
+			ResourceVersion:     lastResourceVersion,
+		})
+		utilruntime.Must(err)
+
+		lastResourceVersion, err = doWatch(ctx, w)
+		if apierrors.IsResourceExpired(err) {
+			lastResourceVersion = ""
+			log.Printf("watch ended with resource expired, retrying with resourceVersion %q: %v", lastResourceVersion, err)
+			continue
+		}
+	}
+}
+
+func doWatch(ctx context.Context, w watch.Interface) (string, error) {
+	defer w.Stop()
+
+	lastResourceVersion := ""
+
+loop:
+	for {
+		select {
+		case <-ctx.Done():
+			break loop
+		case event, ok := <-w.ResultChan():
+			if !ok {
+				break loop
+			}
+
+			if event.Type == watch.Error {
+				return "", apierrors.FromObject(event.Object)
+			}
+
+			var objBytes []byte
+
+			if event.Object != nil {
+				type resourceVersionGetter interface {
+					GetResourceVersion() string
+				}
+
+				if rv, ok := event.Object.(resourceVersionGetter); ok {
+					lastResourceVersion = rv.GetResourceVersion()
+					log.Printf("last resource version: %q", lastResourceVersion)
+				}
+
+				if obj, ok := event.Object.(metav1.Object); ok {
+					obj.SetManagedFields(nil)
+					ann := obj.GetAnnotations()
+					delete(ann, "kubectl.kubernetes.io/last-applied-configuration")
+					obj.SetAnnotations(ann)
+
+					var err error
+					objBytes, err = json.Marshal(obj)
+					if err != nil {
+						return "", err
+					}
+				}
+			}
+
+			log.Printf("%s: %s", event.Type, objBytes)
+		}
+	}
+
+	return lastResourceVersion, nil
+}