gossh

Golang ssh library

Example

package main

import (
  "github.com/dynport/gossh"
  "log"
)

// returns a function of type gossh.Writer func(...interface{})
// MakeLogger just adds a prefix (DEBUG, INFO, ERROR)
func MakeLogger(prefix string) gossh.Writer {
  return func(args ...interface{}) {
    log.Println((append([]interface{}{prefix}, args...))...)
  }
}

func main() {
  client := gossh.New("some.host", "user")
  // my default agent authentication is used. use
  // client.SetPassword("<secret>")
  // client.SetPrivateKey("<PrivateKey path>") if not set this path will read this prv key:$HOME/.ssh/id_rsa 
  // for password authentication
  client.DebugWriter = MakeLogger("DEBUG")
  client.InfoWriter = MakeLogger("INFO ")
  client.ErrorWriter = MakeLogger("ERROR")

  defer client.Close()
  rsp, e := client.Execute("uptime")
  if e != nil {
    client.ErrorWriter(e.Error())
  }
  client.InfoWriter(rsp.String())

  rsp, e = client.Execute("echo -n $(cat /proc/loadavg); cat /does/not/exists")
  if e != nil {
    client.ErrorWriter(e.Error())
    client.ErrorWriter("STDOUT: " + rsp.Stdout())
    client.ErrorWriter("STDERR: " + rsp.Stderr())
  }
}

Prints this result:

2013/08/25 00:31:40 DEBUG connecting some.host
2013/08/25 00:31:41 INFO  [EXEC  ] uptime
2013/08/25 00:31:41 DEBUG 22:31:41 up 375 days, 10:44,  0 users,  load average: 0.09, 0.13, 0.22
2013/08/25 00:31:41 INFO  => 0.944143
2013/08/25 00:31:41 INFO  map[stdout:72 bytes stderr:0 bytes runtime:0.944202 status:0]
2013/08/25 00:31:41 DEBUG already connected
2013/08/25 00:31:41 INFO  [EXEC  ] echo -n $(cat /proc/loadavg); cat /does/not/exists
2013/08/25 00:31:41 DEBUG 0.09 0.13 0.22 1/455 23396
2013/08/25 00:31:41 ERROR cat: /does/not/exists
2013/08/25 00:31:41 ERROR : No such file or directory
2013/08/25 00:31:41 INFO  => 0.067075
2013/08/25 00:31:41 ERROR Process exited with: 1. Reason was:  ()
2013/08/25 00:31:41 ERROR STDOUT: 0.09 0.13 0.22 1/455 23396
2013/08/25 00:31:41 ERROR STDERR: cat: /does/not/exists: No such file or directory

Tunnelling HTTP Connections

For services not bound to the public interface of a machine, tunnelling is a quite nice SSH feature. It allows to use a remote service like it is running at the local machine. This concept is used in the HTTP client returned by the NewHttpClient function. It is a common net/http.Client, but all requests are sent through the SSH connection given.