main.go

/*
Copyright 2020 Red Hat.

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"
	"fmt"
	apimachinerymetav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	apimachineryruntime "k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
	"os"
	"runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/cache"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"
	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"

	appsv1alpha1 "github.com/3scale/apicast-operator/apis/apps/v1alpha1"
	appscontroller "github.com/3scale/apicast-operator/controllers/apps"
	"github.com/3scale/apicast-operator/pkg/k8sutils"
	"github.com/3scale/apicast-operator/pkg/reconcilers"
	"github.com/3scale/apicast-operator/version"
	// +kubebuilder:scaffold:imports
)

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

func init() {
	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
	utilruntime.Must(appsv1alpha1.AddToScheme(scheme))

	// +kubebuilder:scaffold:scheme
}

func main() {
	var metricsAddr string
	var enableLeaderElection bool

	// https://v1-2-x.sdk.operatorframework.io/docs/building-operators/golang/references/logging/#a-simple-example
	// Add the zap logger flag set to the CLI. The flag set must
	// be added before calling flag.Parse().
	loggerOpts := zap.Options{}
	loggerOpts.BindFlags(flag.CommandLine)

	flag.StringVar(&metricsAddr, "metrics-addr", ":8080", "The address the metric endpoint binds to.")
	flag.BoolVar(&enableLeaderElection, "enable-leader-election", false,
		"Enable leader election for controller manager. "+
			"Enabling this will ensure there is only one active controller manager.")
	flag.Parse()

	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&loggerOpts)))

	printVersion()

	namespace, err := getWatchNamespace()
	if err != nil {
		setupLog.Error(err, "Failed to get watch namespace")
		os.Exit(1)
	}

	// If a watch namespace is detected (i.e. operator is namespace scoped), then pass the NS to cache.Options.DefaultNamespaces
	// If no watch namespace is detected (i.e. operator is cluster scoped), then pass an empty Cache object
	var managerCache = cache.Options{}
	if namespace != "" {
		managerCache = cache.Options{
			DefaultNamespaces: map[string]cache.Config{
				namespace: {},
			},
		}
	}

	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
		Cache:            managerCache,
		Scheme:           scheme,
		Metrics:          metricsserver.Options{BindAddress: metricsAddr},
		LeaderElection:   enableLeaderElection,
		LeaderElectionID: "988b4062.3scale.net",
	})
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	secretLabelSelector, err := apimachinerymetav1.ParseToLabelSelector(k8sutils.ApicastSecretLabel)
	if err != nil {
		setupLog.Error(err, "unable parse apicast secrets label")
		os.Exit(1)
	}

	if secretLabelSelector == nil {
		setupLog.Info("secretLabelSelector is empty")
		os.Exit(1)
	}

	if err = (&appscontroller.APIcastReconciler{
		BaseControllerReconciler: reconcilers.NewBaseControllerReconciler(mgr.GetClient(), mgr.GetAPIReader(), mgr.GetScheme()),
		Log:                      ctrl.Log.WithName("controllers").WithName("APIcast"),
		SecretLabelSelector:      *secretLabelSelector,
		WatchedNamespace:         namespace,
	}).SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "APIcast")
		os.Exit(1)
	}
	// +kubebuilder:scaffold:builder

	setupLog.Info("starting manager")
	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}
}

// 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(fmt.Sprintf("Operator Version: %s", version.Version))
	setupLog.Info(fmt.Sprintf("Go Version: %s", runtime.Version()))
	setupLog.Info(fmt.Sprintf("Go OS/Arch: %s/%s", runtime.GOOS, runtime.GOARCH))
}