main.go

/*
Copyright 2022.

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 (
	"crypto/tls"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"runtime"

	"go.uber.org/zap/zapcore"

	pkgruntime "k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"

	// 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"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/healthz"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"
	"sigs.k8s.io/controller-runtime/pkg/webhook"

	fenceagentsremediationv1alpha1 "github.com/medik8s/fence-agents-remediation/api/v1alpha1"
	"github.com/medik8s/fence-agents-remediation/controllers"

	//+kubebuilder:scaffold:imports
	"github.com/medik8s/fence-agents-remediation/pkg/cli"
	"github.com/medik8s/fence-agents-remediation/pkg/validation"
	"github.com/medik8s/fence-agents-remediation/version"
)

const (
	WebhookCertDir  = "/apiserver.local.config/certificates"
	WebhookCertName = "apiserver.crt"
	WebhookKeyName  = "apiserver.key"
	operatorName    = "FenceAgentsRemediation"
)

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

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

	utilruntime.Must(fenceagentsremediationv1alpha1.AddToScheme(scheme))
	//+kubebuilder:scaffold:scheme
}

func main() {
	var (
		metricsAddr          string
		enableLeaderElection bool
		probeAddr            string
		enableHTTP2          bool
		webhookOpts          webhook.Options
	)
	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.")
	flag.BoolVar(&enableHTTP2, "enable-http2", false, "If HTTP/2 should be enabled for the metrics and webhook servers.")

	opts := zap.Options{
		Development: true,
		TimeEncoder: zapcore.RFC3339NanoTimeEncoder,
	}
	opts.BindFlags(flag.CommandLine)
	flag.Parse()

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

	printVersion()

	configureWebhookOpts(&webhookOpts, enableHTTP2)

	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
		Scheme:                 scheme,
		WebhookServer:          webhook.NewServer(webhookOpts),
		HealthProbeBindAddress: probeAddr,
		LeaderElection:         enableLeaderElection,
		LeaderElectionID:       "cb305759.medik8s.io",
	})
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	outOfServiceTaintValidator, err := validation.NewOutOfServiceTaintValidator(mgr.GetConfig())
	if err != nil {
		setupLog.Error(err, "unable to verify Kubernetes version for indicating the out-of-service taint support. out-of-service taint isn't supported")
	}
	isOutOfServiceTaintSupported := outOfServiceTaintValidator.IsOutOfServiceTaintSupported()
	if isOutOfServiceTaintSupported {
		setupLog.Info("out-of-service taint is supported on this cluster")
	}
	fenceagentsremediationv1alpha1.InitOutOfServiceTaintSupportedFlag(isOutOfServiceTaintSupported)

	executer, err := cli.NewExecuter(mgr.GetClient(), mgr.GetEventRecorderFor(operatorName+"-executer"))
	if err != nil {
		setupLog.Error(err, "unable to create executer")
		os.Exit(1)
	}

	if err = (&controllers.FenceAgentsRemediationReconciler{
		Client:   mgr.GetClient(),
		Log:      ctrl.Log.WithName("controllers").WithName(operatorName),
		Scheme:   mgr.GetScheme(),
		Recorder: mgr.GetEventRecorderFor(operatorName),
		Executor: executer,
	}).SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", operatorName)
		os.Exit(1)
	}

	if err = (&fenceagentsremediationv1alpha1.FenceAgentsRemediation{}).SetupWebhookWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create webhook", "webhook", "FenceAgentsRemediation")
		os.Exit(1)
	}
	if err = (&fenceagentsremediationv1alpha1.FenceAgentsRemediationTemplate{}).SetupWebhookWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create webhook", "webhook", "FenceAgentsRemediationTemplate")
		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)
	}
}

func printVersion() {
	setupLog.Info(fmt.Sprintf("Go Version: %s", runtime.Version()))
	setupLog.Info(fmt.Sprintf("Go OS/Arch: %s/%s", runtime.GOOS, runtime.GOARCH))
	setupLog.Info(fmt.Sprintf("Operator Version: %s", version.Version))
	setupLog.Info(fmt.Sprintf("Git Commit: %s", version.GitCommit))
	setupLog.Info(fmt.Sprintf("Build Date: %s", version.BuildDate))
}

func configureWebhookOpts(webhookOpts *webhook.Options, enableHTTP2 bool) {

	certs := []string{filepath.Join(WebhookCertDir, WebhookCertName), filepath.Join(WebhookCertDir, WebhookKeyName)}
	certsInjected := true
	for _, fname := range certs {
		if _, err := os.Stat(fname); err != nil {
			certsInjected = false
			break
		}
	}
	if certsInjected {
		webhookOpts.CertDir = WebhookCertDir
		webhookOpts.CertName = WebhookCertName
		webhookOpts.KeyName = WebhookKeyName
		webhookOpts.TLSOpts = []func(*tls.Config){}
	} else {
		setupLog.Info("OLM injected certs for webhooks not found")
	}
	// disable http/2 for mitigating relevant CVEs
	if !enableHTTP2 {
		webhookOpts.TLSOpts = append(webhookOpts.TLSOpts,
			func(c *tls.Config) {
				c.NextProtos = []string{"http/1.1"}
			},
		)
		setupLog.Info("HTTP/2 for webhooks disabled")
	} else {
		setupLog.Info("HTTP/2 for webhooks enabled")
	}

}