main.go

// Author: Zhang Yifa
// Email: yzhang3@linkernetworks.com

package main

import (
	"fmt"
	"log"
	"os"
	"runtime"

	"github.com/fsouza/go-dockerclient"
	"github.com/spf13/cobra"
	"github.com/zyfdegh/go-dockerpty"
)

func main() {
	//call console
	if err := rootCmd.Execute(); err != nil {
		log.Fatalf("execute command error: %v", err)
		os.Exit(-1)
	}
}

// RootCmd is root command of local-docker-exec
var rootCmd = &cobra.Command{
	Use:     "local-docker-exec [ContainerId]",
	Short:   "local-docker-exec can connect to docker container, and act as a docker exec.",
	Long:    "local-docker-exec can connect to docker container, and act as a docker exec.",
	Example: "./local-docker-exec ffcede5a47cb",
	Run: func(cmd *cobra.Command, args []string) {
		if runtime.GOOS != "linux" {
			log.Fatalln("Only linux is supported now.")
			return
		}

		// example
		// local-docker-exec c3598346f0d7
		if cmd.Flags().NArg() == 1 {
			containerId := cmd.Flags().Args()[0]
			localDockerExec(containerId)
		}

		// others
		cmd.SetArgs([]string{"--help"})
		if err := cmd.Execute(); err != nil {
			log.Fatalf("command arguments error: %v", err)
			os.Exit(-1)
		}
		return
	},
}

func localDockerExec(containerId string) {
	fmt.Println("Welcome to local-docker-exec!")

	endpoint := "unix:///var/run/docker.sock"
	fmt.Printf("Connecting to %s, please wait...\n", endpoint)

	client, err := docker.NewClient(endpoint)
	if err != nil {
		log.Fatalf("new client error: %v\n", err)
	}

	fmt.Printf("Connecting to container %s, please wait...\n", containerId)

	// create exec
	createOpts := docker.CreateExecOptions{}
	createOpts.AttachStdin = true
	createOpts.AttachStdout = true
	createOpts.AttachStderr = true
	createOpts.Tty = true
	// select shell sequence
	// bash -> sh -> zsh -> fish -> csh -> tcsh -> scsh -> ksh -> rc
	createOpts.Cmd = []string{"sh", "-c", "bash || sh || zsh || fish || csh || tcsh || scsh || ksh || rc"}
	createOpts.Container = containerId

	exec, err := client.CreateExec(createOpts)
	if err != nil {
		log.Fatalf("create exec error: %v\n", err)
	}

	// start tty
	err = dockerpty.StartExec(client, exec)
	if err != nil {
		log.Printf("start exec error: %v\n", err)
		return
	}
}