capsule/cmd/manager/main.go

/*
Copyright 2020 Clastix Labs.
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 (
	"context"
	"errors"
	"flag"
	"fmt"
	"os"
	"runtime"
	"strings"

	"github.com/operator-framework/operator-sdk/pkg/k8sutil"
	kubemetrics "github.com/operator-framework/operator-sdk/pkg/kube-metrics"
	"github.com/operator-framework/operator-sdk/pkg/leader"
	"github.com/operator-framework/operator-sdk/pkg/log/zap"
	"github.com/operator-framework/operator-sdk/pkg/metrics"
	sdkVersion "github.com/operator-framework/operator-sdk/version"
	"github.com/spf13/pflag"
	v1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/util/intstr"
	_ "k8s.io/client-go/plugin/pkg/client/auth"
	"k8s.io/client-go/rest"
	"sigs.k8s.io/controller-runtime/pkg/cache"
	"sigs.k8s.io/controller-runtime/pkg/client/config"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/manager"
	"sigs.k8s.io/controller-runtime/pkg/manager/signals"

	"github.com/clastix/capsule/pkg/apis"
	"github.com/clastix/capsule/pkg/controller"
	"github.com/clastix/capsule/pkg/indexer"
	"github.com/clastix/capsule/pkg/webhook"
	"github.com/clastix/capsule/version"
)

// Change below variables to serve metrics on different host or port.
var (
	metricsHost               = "0.0.0.0"
	metricsPort         int32 = 8383
	operatorMetricsPort int32 = 8686
)
var log = logf.Log.WithName("cmd")

func printVersion() {
	log.Info(fmt.Sprintf("Operator Version: %s", version.Version))
	log.Info(fmt.Sprintf("Go Version: %s", runtime.Version()))
	log.Info(fmt.Sprintf("Go OS/Arch: %s/%s", runtime.GOOS, runtime.GOARCH))
	log.Info(fmt.Sprintf("Version of operator-sdk: %v", sdkVersion.Version))
}

func main() {
	// Add the zap logger flag set to the CLI. The flag set must
	// be added before calling pflag.Parse().
	pflag.CommandLine.AddFlagSet(zap.FlagSet())

	// Add flags registered by imported packages (e.g. glog and
	// controller-runtime)
	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)

	var v bool
	pflag.BoolVarP(&v, "version", "v", false, "Print the Capsule version and exit")

	pflag.Parse()

	// Use a zap logr.Logger implementation. If none of the zap
	// flags are configured (or if the zap flag set is not being
	// used), this defaults to a production zap logger.
	//
	// The logger instantiated here can be changed to any logger
	// implementing the logr.Logger interface. This logger will
	// be propagated through the whole operator, generating
	// uniform and structured logs.
	logf.SetLogger(zap.Logger())

	printVersion()
	if v {
		os.Exit(0)
	}

	namespace, err := k8sutil.GetWatchNamespace()
	if err != nil {
		log.Error(err, "Failed to get watch namespace")
		os.Exit(1)
	}

	// Get a config to talk to the apiserver
	cfg, err := config.GetConfig()
	if err != nil {
		log.Error(err, "")
		os.Exit(1)
	}

	ctx := context.TODO()
	// Become the leader before proceeding
	err = leader.Become(ctx, "capsule-lock")
	if err != nil {
		log.Error(err, "")
		os.Exit(1)
	}

	// Set default manager options
	options := manager.Options{
		Namespace:          namespace,
		MetricsBindAddress: fmt.Sprintf("%s:%d", metricsHost, metricsPort),
	}

	// Add support for MultiNamespace set in WATCH_NAMESPACE (e.g ns1,ns2)
	// Note that this is not intended to be used for excluding namespaces, this is better done via a Predicate
	// Also note that you may face performance issues when using this with a high number of namespaces.
	// More Info: https://godoc.org/github.com/kubernetes-sigs/controller-runtime/pkg/cache#MultiNamespacedCacheBuilder
	if strings.Contains(namespace, ",") {
		options.Namespace = ""
		options.NewCache = cache.MultiNamespacedCacheBuilder(strings.Split(namespace, ","))
	}

	stop := signals.SetupSignalHandler()

	// Create a new manager to provide shared dependencies and start components
	mgr, err := manager.New(cfg, options)
	if err != nil {
		log.Error(err, "")
		os.Exit(1)
	}

	log.Info("Registering Components.")

	// Setup Scheme for all resources
	if err := apis.AddToScheme(mgr.GetScheme()); err != nil {
		log.Error(err, "")
		os.Exit(1)
	}

	// Setup all Controllers
	if err := controller.AddToManager(mgr); err != nil {
		log.Error(err, "")
		os.Exit(1)
	}

	// Setup all Webhooks
	if err := webhook.AddToServer(mgr); err != nil {
		log.Error(err, "")
		os.Exit(1)
	}

	// Setup all Custom Indexers
	if err := indexer.AddToManager(mgr); err != nil {
		log.Error(err, "")
		os.Exit(1)
	}

	// Add the Metrics Service
	addMetrics(ctx, cfg)

	log.Info("Starting the Cmd.")

	// Start the Cmd
	if err := mgr.Start(stop); err != nil {
		log.Error(err, "Manager exited non-zero")
		os.Exit(1)
	}
}

// addMetrics will create the Services and Service Monitors to allow the operator export the metrics by using
// the Prometheus operator
func addMetrics(ctx context.Context, cfg *rest.Config) {
	// Get the namespace the operator is currently deployed in.
	operatorNs, err := k8sutil.GetOperatorNamespace()
	if err != nil {
		if errors.Is(err, k8sutil.ErrRunLocal) {
			log.Info("Skipping CR metrics server creation; not running in a cluster.")
			return
		}
	}

	if err := serveCRMetrics(cfg, operatorNs); err != nil {
		log.Info("Could not generate and serve custom resource metrics", "error", err.Error())
	}

	// Add to the below struct any other metrics ports you want to expose.
	servicePorts := []v1.ServicePort{
		{Port: metricsPort, Name: metrics.OperatorPortName, Protocol: v1.ProtocolTCP, TargetPort: intstr.IntOrString{Type: intstr.Int, IntVal: metricsPort}},
		{Port: operatorMetricsPort, Name: metrics.CRPortName, Protocol: v1.ProtocolTCP, TargetPort: intstr.IntOrString{Type: intstr.Int, IntVal: operatorMetricsPort}},
	}

	// Create Service object to expose the metrics port(s).
	service, err := metrics.CreateMetricsService(ctx, cfg, servicePorts)
	if err != nil {
		log.Info("Could not create metrics Service", "error", err.Error())
	}

	// CreateServiceMonitors will automatically create the prometheus-operator ServiceMonitor resources
	// necessary to configure Prometheus to scrape metrics from this operator.
	services := []*v1.Service{service}

	// The ServiceMonitor is created in the same namespace where the operator is deployed
	_, err = metrics.CreateServiceMonitors(cfg, operatorNs, services)
	if err != nil {
		log.Info("Could not create ServiceMonitor object", "error", err.Error())
		// If this operator is deployed to a cluster without the prometheus-operator running, it will return
		// ErrServiceMonitorNotPresent, which can be used to safely skip ServiceMonitor creation.
		if err == metrics.ErrServiceMonitorNotPresent {
			log.Info("Install prometheus-operator in your cluster to create ServiceMonitor objects", "error", err.Error())
		}
	}
}

// serveCRMetrics gets the Operator/CustomResource GVKs and generates metrics based on those types.
// It serves those metrics on "http://metricsHost:operatorMetricsPort".
func serveCRMetrics(cfg *rest.Config, operatorNs string) error {
	// The function below returns a list of filtered operator/CR specific GVKs. For more control, override the GVK list below
	// with your own custom logic. Note that if you are adding third party API schemas, probably you will need to
	// customize this implementation to avoid permissions issues.
	filteredGVK, err := k8sutil.GetGVKsFromAddToScheme(apis.AddToScheme)
	if err != nil {
		return err
	}

	// The metrics will be generated from the namespaces which are returned here.
	// NOTE that passing nil or an empty list of namespaces in GenerateAndServeCRMetrics will result in an error.
	ns, err := kubemetrics.GetNamespacesForMetrics(operatorNs)
	if err != nil {
		return err
	}

	// Generate and serve custom resource specific metrics.
	err = kubemetrics.GenerateAndServeCRMetrics(cfg, ns, filteredGVK, metricsHost, operatorMetricsPort)
	if err != nil {
		return err
	}
	return nil
}