kubesphere/cmd/ks-apiserver/app/server.go

/*
Copyright 2019 The KubeSphere Authors.

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 app

import (
	"context"
	"fmt"
	"net/http"

	"github.com/google/gops/agent"
	"github.com/spf13/cobra"
	utilerrors "k8s.io/apimachinery/pkg/util/errors"
	cliflag "k8s.io/component-base/cli/flag"
	"k8s.io/klog/v2"

	"sigs.k8s.io/controller-runtime/pkg/manager/signals"

	"kubesphere.io/kubesphere/cmd/ks-apiserver/app/options"
	apiserverconfig "kubesphere.io/kubesphere/pkg/apiserver/config"
	"kubesphere.io/kubesphere/pkg/utils/term"
	"kubesphere.io/kubesphere/pkg/version"
)

func NewAPIServerCommand() *cobra.Command {
	s := options.NewServerRunOptions()

	// Load configuration from file
	conf, err := apiserverconfig.TryLoadFromDisk()
	if err == nil {
		s.Config = conf
	} else {
		klog.Fatalf("Failed to load configuration from disk: %v", err)
	}

	cmd := &cobra.Command{
		Use: "ks-apiserver",
		Long: `The KubeSphere API server validates and configures data for the API objects. 
The API Server services REST operations and provides the frontend to the
cluster's shared state through which all other components interact.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			if errs := s.Validate(); len(errs) != 0 {
				return utilerrors.NewAggregate(errs)
			}

			if s.GOPSEnabled {
				// Add agent to report additional information such as the current stack trace, Go version, memory stats, etc.
				// Bind to a random port on address 127.0.0.1.
				if err := agent.Listen(agent.Options{}); err != nil {
					klog.Fatal(err)
				}
			}

			return Run(s, apiserverconfig.WatchConfigChange(), signals.SetupSignalHandler())
		},
		SilenceUsage: true,
	}

	fs := cmd.Flags()
	namedFlagSets := s.Flags()
	for _, f := range namedFlagSets.FlagSets {
		fs.AddFlagSet(f)
	}

	usageFmt := "Usage:\n  %s\n"
	cols, _, _ := term.TerminalSize(cmd.OutOrStdout())
	cmd.SetHelpFunc(func(cmd *cobra.Command, args []string) {
		fmt.Fprintf(cmd.OutOrStdout(), "%s\n\n"+usageFmt, cmd.Long, cmd.UseLine())
		cliflag.PrintSections(cmd.OutOrStdout(), namedFlagSets, cols)
	})

	versionCmd := &cobra.Command{
		Use:   "version",
		Short: "Print the version of KubeSphere ks-apiserver",
		Run: func(cmd *cobra.Command, args []string) {
			cmd.Println(version.Get())
		},
	}

	cmd.AddCommand(versionCmd)

	return cmd
}

func Run(s *options.ServerRunOptions, configCh <-chan apiserverconfig.Config, ctx context.Context) error {
	ictx, cancelFunc := context.WithCancel(context.TODO())
	errCh := make(chan error)
	defer close(errCh)
	go func() {
		if err := run(s, ictx); err != nil {
			errCh <- err
		}
	}()

	// The ctx (signals.SetupSignalHandler()) is to control the entire program life cycle,
	// The ictx(internal context)  is created here to control the life cycle of the ks-apiserver(http server, sharedInformer etc.)
	// when config change, stop server and renew context, start new server
	for {
		select {
		case <-ctx.Done():
			cancelFunc()
			return nil
		case cfg := <-configCh:
			cancelFunc()
			s.Config = &cfg
			ictx, cancelFunc = context.WithCancel(context.TODO())
			go func() {
				if errs := s.Validate(); len(errs) != 0 {
					for _, err := range errs {
						errCh <- err
					}
				}
				if err := run(s, ictx); err != nil {
					errCh <- err
				}
			}()
		case err := <-errCh:
			cancelFunc()
			return err
		}
	}
}

func run(s *options.ServerRunOptions, ctx context.Context) error {
	apiserver, err := s.NewAPIServer(ctx.Done())
	if err != nil {
		return err
	}

	err = apiserver.PrepareRun(ctx.Done())
	if err != nil {
		return err
	}

	err = apiserver.Run(ctx)
	if err == http.ErrServerClosed {
		return nil
	}
	return err
}