main.go

/*
   Copyright The containerd 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 command

import (
	"context"
	"fmt"
	"io/ioutil"
	golog "log"
	"net"
	"os"
	"os/signal"
	"path/filepath"
	"time"

	"github.com/containerd/containerd/log"
	"github.com/containerd/containerd/mount"
	"github.com/containerd/containerd/server"
	"github.com/containerd/containerd/sys"
	"github.com/containerd/containerd/version"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"github.com/urfave/cli"
	gocontext "golang.org/x/net/context"
	"google.golang.org/grpc/grpclog"
)

const usage = `
                    __        _                     __
  _________  ____  / /_____ _(_)___  ___  _________/ /
 / ___/ __ \/ __ \/ __/ __ ` + "`" + `/ / __ \/ _ \/ ___/ __  /
/ /__/ /_/ / / / / /_/ /_/ / / / / /  __/ /  / /_/ /
\___/\____/_/ /_/\__/\__,_/_/_/ /_/\___/_/   \__,_/

high performance container runtime
`

func init() {
	// Discard grpc logs so that they don't mess with our stdio
	grpclog.SetLogger(golog.New(ioutil.Discard, "", golog.LstdFlags))

	cli.VersionPrinter = func(c *cli.Context) {
		fmt.Println(c.App.Name, version.Package, c.App.Version, version.Revision)
	}
}

// App returns a *cli.App instance.
func App() *cli.App {
	app := cli.NewApp()
	app.Name = "containerd"
	app.Version = version.Version
	app.Usage = usage
	app.Flags = []cli.Flag{
		cli.StringFlag{
			Name:  "config,c",
			Usage: "path to the configuration file",
			Value: defaultConfigPath,
		},
		cli.StringFlag{
			Name:  "log-level,l",
			Usage: "set the logging level [trace, debug, info, warn, error, fatal, panic]",
		},
		cli.StringFlag{
			Name:  "address,a",
			Usage: "address for containerd's GRPC server",
		},
		cli.StringFlag{
			Name:  "root",
			Usage: "containerd root directory",
		},
		cli.StringFlag{
			Name:  "state",
			Usage: "containerd state directory",
		},
	}
	app.Commands = []cli.Command{
		configCommand,
		publishCommand,
	}
	app.Action = func(context *cli.Context) error {
		var (
			start   = time.Now()
			signals = make(chan os.Signal, 2048)
			serverC = make(chan *server.Server, 1)
			ctx     = gocontext.Background()
			config  = defaultConfig()
		)

		done := handleSignals(ctx, signals, serverC)
		// start the signal handler as soon as we can to make sure that
		// we don't miss any signals during boot
		signal.Notify(signals, handledSignals...)

		if err := server.LoadConfig(context.GlobalString("config"), config); err != nil && !os.IsNotExist(err) {
			return err
		}
		// apply flags to the config
		if err := applyFlags(context, config); err != nil {
			return err
		}
		// cleanup temp mounts
		if err := mount.SetTempMountLocation(filepath.Join(config.Root, "tmpmounts")); err != nil {
			return errors.Wrap(err, "creating temp mount location")
		}
		// unmount all temp mounts on boot for the server
		if err := mount.CleanupTempMounts(0); err != nil {
			return errors.Wrap(err, "unmounting temp mounts")
		}
		address := config.GRPC.Address
		if address == "" {
			return errors.New("grpc address cannot be empty")
		}
		log.G(ctx).WithFields(logrus.Fields{
			"version":  version.Version,
			"revision": version.Revision,
		}).Info("starting containerd")

		server, err := server.New(ctx, config)
		if err != nil {
			return err
		}
		serverC <- server
		if config.Debug.Address != "" {
			var l net.Listener
			if filepath.IsAbs(config.Debug.Address) {
				if l, err = sys.GetLocalListener(config.Debug.Address, config.Debug.UID, config.Debug.GID); err != nil {
					return errors.Wrapf(err, "failed to get listener for debug endpoint")
				}
			} else {
				if l, err = net.Listen("tcp", config.Debug.Address); err != nil {
					return errors.Wrapf(err, "failed to get listener for debug endpoint")
				}
			}
			serve(ctx, l, server.ServeDebug)
		}
		if config.Metrics.Address != "" {
			l, err := net.Listen("tcp", config.Metrics.Address)
			if err != nil {
				return errors.Wrapf(err, "failed to get listener for metrics endpoint")
			}
			serve(ctx, l, server.ServeMetrics)
		}

		l, err := sys.GetLocalListener(address, config.GRPC.UID, config.GRPC.GID)
		if err != nil {
			return errors.Wrapf(err, "failed to get listener for main endpoint")
		}
		serve(ctx, l, server.ServeGRPC)

		log.G(ctx).Infof("containerd successfully booted in %fs", time.Since(start).Seconds())
		<-done
		return nil
	}
	return app
}

func serve(ctx context.Context, l net.Listener, serveFunc func(net.Listener) error) {
	path := l.Addr().String()
	log.G(ctx).WithField("address", path).Info("serving...")
	go func() {
		defer l.Close()
		if err := serveFunc(l); err != nil {
			log.G(ctx).WithError(err).WithField("address", path).Fatal("serve failure")
		}
	}()
}

func applyFlags(context *cli.Context, config *server.Config) error {
	// the order for config vs flag values is that flags will always override
	// the config values if they are set
	if err := setLevel(context, config); err != nil {
		return err
	}
	for _, v := range []struct {
		name string
		d    *string
	}{
		{
			name: "root",
			d:    &config.Root,
		},
		{
			name: "state",
			d:    &config.State,
		},
		{
			name: "address",
			d:    &config.GRPC.Address,
		},
	} {
		if s := context.GlobalString(v.name); s != "" {
			*v.d = s
		}
	}
	return nil
}

func setLevel(context *cli.Context, config *server.Config) error {
	l := context.GlobalString("log-level")
	if l == "" {
		l = config.Debug.Level
	}
	if l != "" {
		lvl, err := log.ParseLevel(l)
		if err != nil {
			return err
		}
		logrus.SetLevel(lvl)
	}
	return nil
}