main.go

//
// Copyright (c) 2012-2021 Red Hat, Inc.
// This program and the accompanying materials are made
// available under the terms of the Eclipse Public License 2.0
// which is available at https://www.eclipse.org/legal/epl-2.0/
//
// SPDX-License-Identifier: EPL-2.0
//
// Contributors:
//   Red Hat, Inc. - initial API and implementation
//

package main

import (
	"flag"
	"fmt"
	"os"

	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/selection"
	"sigs.k8s.io/controller-runtime/pkg/cache"

	// 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"

	go_runtime "runtime"

	"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"

	orgv1alpha1 "github.com/che-incubator/kubernetes-image-puller-operator/api/v1alpha1"
	"github.com/che-incubator/kubernetes-image-puller-operator/controllers"
	//+kubebuilder:scaffold:imports
)

var (
	scheme   = runtime.NewScheme()
	setupLog = ctrl.Log.WithName("setup")
)

func init() {
	utilruntime.Must(clientgoscheme.AddToScheme(scheme))

	utilruntime.Must(orgv1alpha1.AddToScheme(scheme))
	//+kubebuilder:scaffold:scheme
}

// getWatchNamespace returns the Namespace the operator should be watching for changes
func getWatchNamespace() (string, error) {
	// WatchNamespaceEnvVar is the constant for env variable WATCH_NAMESPACE
	// which specifies the Namespace to watch.
	// An empty value means the operator is running with cluster scope.
	var watchNamespaceEnvVar = "WATCH_NAMESPACE"

	ns, found := os.LookupEnv(watchNamespaceEnvVar)
	if !found {
		return "", fmt.Errorf("%s must be set", watchNamespaceEnvVar)
	}

	return ns, nil
}

func printVersion() {
	setupLog.Info("Go", "Version: ", go_runtime.Version())
	setupLog.Info("Go ", "OS", go_runtime.GOOS, "Arch:", go_runtime.GOARCH)
}

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)))
	printVersion()

	watchNamespace, err := getWatchNamespace()
	if err != nil {
		setupLog.Error(err, "unable to get WatchNamespace, "+
			"the manager will watch and manage resources in all Namespaces")
	}

	cacheFunction, err := getCacheFunc()
	if err != nil {
		setupLog.Error(err, "failed to create cache function")
		os.Exit(1)
	}

	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
		Scheme:                 scheme,
		MetricsBindAddress:     metricsAddr,
		Port:                   9443,
		HealthProbeBindAddress: probeAddr,
		LeaderElection:         enableLeaderElection,
		LeaderElectionID:       "06ff708d.eclipse.che",
		Namespace:              watchNamespace,
		NewCache:               cacheFunction,
	})
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	imagePullerController := &controllers.KubernetesImagePullerReconciler{
		Client: mgr.GetClient(),
		Log:    ctrl.Log.WithName("controllers").WithName("KubernetesImagePuller"),
		Scheme: mgr.GetScheme(),
	}

	if err = imagePullerController.SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "KubernetesImagePuller")
		os.Exit(1)
	}

	if err = (&orgv1alpha1.KubernetesImagePuller{}).SetupWebhookWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create webhook", "webhook", "KubernetesImagePuller")
		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)
	}
}

// getCacheFunc allows to limit cache for objects by label selector.
func getCacheFunc() (cache.NewCacheFunc, error) {
	kubernetesImagePullerApp, err := labels.NewRequirement("app", selection.Equals, []string{"kubernetes-image-puller"})
	if err != nil {
		return nil, err
	}
	kubernetesImagePullerAppSelector := labels.NewSelector().Add(*kubernetesImagePullerApp)

	setupLog.Info("Cache with selector", "app", "kubernetes-image-puller")

	selectors := cache.SelectorsByObject{
		&appsv1.Deployment{}: {
			Label: kubernetesImagePullerAppSelector,
		},
		&corev1.Pod{}: {
			Label: kubernetesImagePullerAppSelector,
		},
		&corev1.ConfigMap{}: {
			Label: kubernetesImagePullerAppSelector,
		},
	}

	return cache.BuilderWithOptions(cache.Options{
		SelectorsByObject: selectors,
	}), nil
}