gistfile1.go

package main

import (
	"bytes"
	"code.google.com/p/go.crypto/ssh"
	"fmt"
	"io/ioutil"
	"os"
	"time"
)

func makeSigner(keyname string) (signer ssh.Signer, err error) {
	fp, err := os.Open(keyname)
	if err != nil {
		return
	}
	defer fp.Close()

	buf, _ := ioutil.ReadAll(fp)
	signer, _ = ssh.ParsePrivateKey(buf)
	return
}

func executeCmd(cmd, hostname string, config *ssh.ClientConfig) (string, error) {
	conn, err := ssh.Dial("tcp", hostname+":22", config)
	if err != nil {
		return "", err
	}
	session, err := conn.NewSession()
	if err != nil {
		return "", err
	}
	defer session.Close()

	var stdoutBuf bytes.Buffer
	session.Stdout = &stdoutBuf
	session.Run(cmd)

	return hostname + ": " + stdoutBuf.String(), nil
}

func main() {
	cmd := os.Args[1]
	hosts := os.Args[2:]

	keyPath := os.Getenv("HOME") + "/.ssh/id_rsa"
	results := make(chan string, 10)
	timeout := time.After(5 * time.Second)
	signer, err := makeSigner(keyPath)
	if err != nil {
		fmt.Println("Couldn't get private key")
		return
	}
	config := &ssh.ClientConfig{
		User: os.Getenv("LOGNAME"),
		Auth: []ssh.AuthMethod{ssh.PublicKeys(signer)},
	}

	for _, hostname := range hosts {
		go func(hostname string) {
			result, err := executeCmd(cmd, hostname, config)
			if err != nil {
				fmt.Println("error: ", err)
				return
			}
			results <- result
		}(hostname)
	}

	for i := 0; i < len(hosts); i++ {
		select {
		case res := <-results:
			fmt.Print(res)
		case <-timeout:
			fmt.Println("Timed out!")
			return
		}
	}
}