dsh.go

package main

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"os/exec"
	"strconv"
	"strings"
	"text/tabwriter"
	"time"

	"github.com/dotcloud/docker/pkg/units"
	"github.com/samalba/dockerclient"
)

var (
	builtins = map[string]func([]string) error{
		"exit": exit,
		"ps":   ps,
		"kill": kill,
		"ls":   ls,
	}

	docker *dockerclient.DockerClient
)

func init() {
	var err error

	if docker, err = dockerclient.NewDockerClient(os.Getenv("DOCKER_HOST"), nil); err != nil {
		log.Fatal(err)
	}
}

func exit(args []string) error {
	code := 0

	if len(args) == 1 {
		c, err := strconv.Atoi(args[0])
		if err != nil {
			return err
		}
		code = c
	}

	os.Exit(code)

	return nil
}

func ps(args []string) error {
	containers, err := docker.ListContainers(false)
	if err != nil {
		return err
	}

	w := tabwriter.NewWriter(os.Stdout, 10, 1, 3, ' ', 0)
	fmt.Fprintf(w, "ID\tIMAGE\tCMD\n")

	for _, c := range containers {
		fmt.Fprintf(w, "%s\t%s\t%s\n", c.Id[0:5], c.Image, c.Command)
	}

	w.Flush()

	return nil
}

func kill(args []string) error {
	return docker.KillContainer(args[0])
}

func ls(args []string) error {
	images, err := docker.ListImages()
	if err != nil {
		return err
	}

	w := tabwriter.NewWriter(os.Stdout, 10, 1, 3, ' ', 0)
	fmt.Fprintf(w, "ID\tSIZE\tDATE\tNAME\n")

	for _, i := range images {
		if strings.Contains(i.RepoTags[0], "<none>") {
			continue
		}

		t := time.Unix(i.Created, 0).Format("Jan 02")

		fmt.Fprintf(w, "%s\t%s\t%s\t%s\n", i.Id[:5], units.HumanSize(i.VirtualSize), t, i.RepoTags[0])
	}

	w.Flush()

	return nil
}

func main() {
	s := bufio.NewScanner(os.Stdin)

	fmt.Fprintln(os.Stdout, "the shell for the 2000nds")
	fmt.Fprintf(os.Stdout, ">")

	for s.Scan() {
		tokens := strings.Split(s.Text(), " ")

		if b, exists := builtins[tokens[0]]; exists {
			if err := b(tokens[1:]); err != nil {
				log.Fatal(err)
			}

			fmt.Fprintf(os.Stdout, ">")

			continue
		}

		cmd := exec.Command(tokens[0], tokens[1:]...)

		cmd.Stdin = os.Stdin
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr

		if err := cmd.Run(); err != nil {
			log.Fatal(err)
		}

		fmt.Fprintf(os.Stdout, ">")
	}
}