Enable controller-runtime backwards-compatibility

Make kdp backwards-compatible with versions of controller-runtime before
v0.16, which introduced the metrics/server package.

examples/guestbook-operator/main11.go

@@ -0,0 +1,108 @@
+//go:build controllerruntime_11 || controllerruntime_12 || controllerruntime_13 || controllerruntime_14 || controllerruntime_15
+
+/*
+Copyright 2020 The Kubernetes 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 (
+	"flag"
+	"os"
+
+	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
+	// to ensure that exec-entrypoint and run can make use of them.
+	_ "k8s.io/client-go/plugin/pkg/client/auth"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/healthz"
+	"sigs.k8s.io/controller-runtime/pkg/log/zap"
+	"sigs.k8s.io/kubebuilder-declarative-pattern/pkg/patterns/addon"
+
+	addonsv1alpha1 "sigs.k8s.io/kubebuilder-declarative-pattern/examples/guestbook-operator/api/v1alpha1"
+	"sigs.k8s.io/kubebuilder-declarative-pattern/examples/guestbook-operator/controllers"
+	//+kubebuilder:scaffold:imports
+)
+
+var (
+	scheme   = runtime.NewScheme()
+	setupLog = ctrl.Log.WithName("setup")
+)
+
+func init() {
+	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
+
+	utilruntime.Must(addonsv1alpha1.AddToScheme(scheme))
+	//+kubebuilder:scaffold:scheme
+}
+
+func main() {
+	var metricsAddr string
+	var enableLeaderElection bool
+	var probeAddr string
+	flag.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the metric endpoint binds to.")
+	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
+	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
+		"Enable leader election for controller manager. "+
+			"Enabling this will ensure there is only one active controller manager.")
+	opts := zap.Options{
+		Development: true,
+	}
+	opts.BindFlags(flag.CommandLine)
+	flag.Parse()
+
+	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))
+	addon.Init()
+
+	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
+		Scheme:                 scheme,
+		MetricsBindAddress:     metricsAddr,
+		Port:                   9443,
+		HealthProbeBindAddress: probeAddr,
+		LeaderElection:         enableLeaderElection,
+		LeaderElectionID:       "c3cffa1a.example.org",
+	})
+	if err != nil {
+		setupLog.Error(err, "unable to start manager")
+		os.Exit(1)
+	}
+
+	if err = (&controllers.GuestbookReconciler{
+		Client: mgr.GetClient(),
+		Scheme: mgr.GetScheme(),
+	}).SetupWithManager(mgr); err != nil {
+		setupLog.Error(err, "unable to create controller", "controller", "Guestbook")
+		os.Exit(1)
+	}
+	//+kubebuilder:scaffold:builder
+
+	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {
+		setupLog.Error(err, "unable to set up health check")
+		os.Exit(1)
+	}
+	if err := mgr.AddReadyzCheck("readyz", healthz.Ping); err != nil {
+		setupLog.Error(err, "unable to set up ready check")
+		os.Exit(1)
+	}
+
+	setupLog.Info("starting manager")
+	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
+		setupLog.Error(err, "problem running manager")
+		os.Exit(1)
+	}
+}

examples/guestbook-operator/main.go → examples/guestbook-operator/main16.go

@@ -1,3 +1,5 @@
+//go:build !(controllerruntime_11 || controllerruntime_12 || controllerruntime_13 || controllerruntime_14 || controllerruntime_15)
+
 /*
 Copyright 2020 The Kubernetes Authors.