moby/cmd/dockerd/docker.go

package main

import (
	"fmt"
	"os"
	"runtime"

	"github.com/docker/docker/cli"
	"github.com/docker/docker/daemon/config"
	"github.com/docker/docker/dockerversion"
	"github.com/docker/docker/pkg/reexec"
	"github.com/docker/docker/pkg/term"
	"github.com/sirupsen/logrus"
	"github.com/spf13/cobra"
)

func newDaemonCommand() *cobra.Command {
	opts := newDaemonOptions(config.New())

	cmd := &cobra.Command{
		Use:           "dockerd [OPTIONS]",
		Short:         "A self-sufficient runtime for containers.",
		SilenceUsage:  true,
		SilenceErrors: true,
		Args:          cli.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			if opts.version {
				showVersion()
				return nil
			}
			opts.flags = cmd.Flags()
			return runDaemon(opts)
		},
	}
	cli.SetupRootCommand(cmd)

	flags := cmd.Flags()
	flags.BoolVarP(&opts.version, "version", "v", false, "Print version information and quit")
	flags.StringVar(&opts.configFile, "config-file", defaultDaemonConfigFile, "Daemon configuration file")
	opts.InstallFlags(flags)
	installConfigFlags(opts.daemonConfig, flags)
	installServiceFlags(flags)

	return cmd
}

func showVersion() {
	fmt.Printf("Docker version %s, build %s\n", dockerversion.Version, dockerversion.GitCommit)
}

func main() {
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	_, stdout, stderr := term.StdStreams()

	// @jhowardmsft - maybe there is a historic reason why on non-Windows, stderr is used
	// here. However, on Windows it makes no sense and there is no need.
	if runtime.GOOS == "windows" {
		logrus.SetOutput(stdout)
	} else {
		logrus.SetOutput(stderr)
	}

	cmd := newDaemonCommand()
	cmd.SetOutput(stdout)
	if err := cmd.Execute(); err != nil {
		fmt.Fprintf(stderr, "%s\n", err)
		os.Exit(1)
	}
}