main.go

/*
Copyright 2023 Solace Corporation

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"
	"os"
	ctrlruntime_cache "sigs.k8s.io/controller-runtime/pkg/cache"
	"sigs.k8s.io/controller-runtime/pkg/metrics/server"
	"strings"

	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
	// to ensure that exec-entrypoint and run can make use of them.
	"go.uber.org/zap/zapcore"
	"k8s.io/client-go/discovery"
	_ "k8s.io/client-go/plugin/pkg/client/auth"
	"k8s.io/client-go/rest"

	"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"

	pubsubplusv1beta1 "github.com/SolaceProducts/pubsubplus-operator/api/v1beta1"
	"github.com/SolaceProducts/pubsubplus-operator/controllers"
	//+kubebuilder:scaffold:imports
)

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

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

	utilruntime.Must(pubsubplusv1beta1.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.")
	// Followings are default options for the logger, can be overwritten by comand-line options
	opts := zap.Options{
		Development: true,
		TimeEncoder: zapcore.RFC3339NanoTimeEncoder,
	}
	opts.BindFlags(flag.CommandLine)
	flag.Parse()

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

	// Create Manager
	options := ctrl.Options{
		Scheme: scheme,
		Metrics: server.Options{
			BindAddress: metricsAddr,
		},
		HealthProbeBindAddress: probeAddr,
		LeaderElection:         enableLeaderElection,
		LeaderElectionID:       "cb271b96.solace.com",
	}
	// Add support for multiple namespaces given in WATCH_NAMESPACE (e.g. ns1,ns2)
	watchNs, err := getWatchNamespace()
	if err != nil {
		setupLog.Error(err, "Failed to get watch namespace")
		os.Exit(1)
	}
	if watchNs != "" {
		setupLog.Info(fmt.Sprintf("Watching following namespace(s): %s", watchNs))
		if strings.Contains(watchNs, ",") {
			nsList := strings.Split(watchNs, ",")
			options.Cache.DefaultNamespaces = make(map[string]ctrlruntime_cache.Config)
			for _, namespace := range nsList {
				options.Cache.DefaultNamespaces[namespace] = ctrlruntime_cache.Config{}
			}
		} else {
			options.Cache = ctrlruntime_cache.Options{
				DefaultNamespaces: map[string]ctrlruntime_cache.Config{watchNs: {}},
			}
		}
	} else {
		setupLog.Info("Watching all namespaces")
	}

	cfg := ctrl.GetConfigOrDie()
	mgr, err := ctrl.NewManager(cfg, options)
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}
	if err = (&controllers.PubSubPlusEventBrokerReconciler{
		Client:      mgr.GetClient(),
		Scheme:      mgr.GetScheme(),
		Recorder:    mgr.GetEventRecorderFor("PubSubPlusEventBroker"),
		IsOpenShift: detectOpenShift(cfg),
	}).SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "PubSubPlusEventBroker")
		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)
	}
}

// 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
}

// detectOpenShift returns true if OpenShift environment has been identified
func detectOpenShift(cfg *rest.Config) bool {
	// Note: there could be additional checks here or env variable to force.
	dclient, err := getDiscoveryClient(cfg)
	if err == nil && dclient != nil {
		apiGroupList, err := dclient.ServerGroups()
		if err == nil {
			openShiftAPIGroupOccurrenceCount := 0 // Let's ensure to have a number of (>5) evidences that this is indeed OpenShift
			for i := 0; i < len(apiGroupList.Groups); i++ {
				if strings.HasSuffix(apiGroupList.Groups[i].Name, ".openshift.io") {
					openShiftAPIGroupOccurrenceCount++
					if openShiftAPIGroupOccurrenceCount > 5 {
						setupLog.Info("Identified OpenShift environment")
						return true
					}
				}
			}
		}
	}
	setupLog.Info("Identified general Kubernetes environment")
	return false
}

// getDiscoveryClient returns a discovery client for the current reconciler
func getDiscoveryClient(config *rest.Config) (*discovery.DiscoveryClient, error) {
	return discovery.NewDiscoveryClientForConfig(config)
}