runc/main.go

package main

import (
	"fmt"
	"os"

	"github.com/Sirupsen/logrus"
	"github.com/codegangsta/cli"
	"github.com/opencontainers/specs"
)

const (
	version    = "0.0.8"
	specConfig = "config.json"
	usage      = `Open Container Initiative runtime
	
runc is a command line client for running applications packaged according to
the Open Container Format (OCF) and is a compliant implementation of the
Open Container Initiative specification.

runc integrates well with existing process supervisors to provide a production
container runtime environment for applications. It can be used with your
existing process monitoring tools and the container will be spawned as a
direct child of the process supervisor.

Containers are configured using bundles. A bundle for a container is a directory
that includes a specification file named "` + specConfig + `" and a root filesystem.
The root filesystem contains the contents of the container. 

To start a new instance of a container:

    # runc start [ -b bundle ] <container-id>

Where "<container-id>" is your name for the instance of the container that you
are starting. The name you provide for the container instance must be unique on
your host. Providing the bundle directory using "-b" is optional. The default
value for "bundle" is the current directory.`
)

func main() {
	app := cli.NewApp()
	app.Name = "runc"
	app.Usage = usage
	app.Version = fmt.Sprintf("%s\nspec version %s", version, specs.Version)
	app.Flags = []cli.Flag{
		cli.BoolFlag{
			Name:  "debug",
			Usage: "enable debug output for logging",
		},
		cli.StringFlag{
			Name:  "log",
			Usage: "set the log file path where internal debug information is written",
		},
		cli.StringFlag{
			Name:  "log-format",
			Value: "text",
			Usage: "set the format used by logs ('text' (default), or 'json')",
		},
		cli.StringFlag{
			Name:  "root",
			Value: specs.LinuxStateDirectory,
			Usage: "root directory for storage of container state (this should be located in tmpfs)",
		},
		cli.StringFlag{
			Name:  "criu",
			Value: "criu",
			Usage: "path to the criu binary used for checkpoint and restore",
		},
	}
	app.Commands = []cli.Command{
		checkpointCommand,
		deleteCommand,
		eventsCommand,
		execCommand,
		killCommand,
		listCommand,
		pauseCommand,
		restoreCommand,
		resumeCommand,
		specCommand,
		startCommand,
	}
	app.Before = func(context *cli.Context) error {
		if context.GlobalBool("debug") {
			logrus.SetLevel(logrus.DebugLevel)
		}
		if path := context.GlobalString("log"); path != "" {
			f, err := os.Create(path)
			if err != nil {
				return err
			}
			logrus.SetOutput(f)
		}
		switch context.GlobalString("log-format") {
		case "text":
			// retain logrus's default.
		case "json":
			logrus.SetFormatter(new(logrus.JSONFormatter))
		default:
			logrus.Fatalf("unknown log-format %q", context.GlobalString("log-format"))
		}
		return nil
	}
	if err := app.Run(os.Args); err != nil {
		logrus.Fatal(err)
	}
}