func makeSSHTunnel(user string, signer ssh.Signer, host string) (*SSHTunnel, error) {
config := ssh.ClientConfig{
User: user,
Auth: []ssh.AuthMethod{ssh.PublicKeys(signer)},
}
return &SSHTunnel{
Config: &config,
Host: host,
SSHPort: "22",
}, nil
}
// Internal implementation of runSSHCommand, for testing
func runSSHCommand(dialer sshDialer, cmd, user, host string, signer ssh.Signer) (string, string, int, error) {
if user == "" {
user = os.Getenv("USER")
}
// Setup the config, dial the server, and open a session.
config := &ssh.ClientConfig{
User: user,
Auth: []ssh.AuthMethod{ssh.PublicKeys(signer)},
}
client, err := dialer.Dial("tcp", host, config)
if err != nil {
return "", "", 0, fmt.Errorf("error getting SSH client to %s@%s: '%v'", user, host, err)
}
session, err := client.NewSession()
if err != nil {
return "", "", 0, fmt.Errorf("error creating session to %s@%s: '%v'", user, host, err)
}
defer session.Close()
// Run the command.
code := 0
var bout, berr bytes.Buffer
session.Stdout, session.Stderr = &bout, &berr
if err = session.Run(cmd); err != nil {
// Check whether the command failed to run or didn't complete.
if exiterr, ok := err.(*ssh.ExitError); ok {
// If we got an ExitError and the exit code is nonzero, we'll
// consider the SSH itself successful (just that the command run
// errored on the host).
if code = exiterr.ExitStatus(); code != 0 {
err = nil
}
} else {
// Some other kind of error happened (e.g. an IOError); consider the
// SSH unsuccessful.
err = fmt.Errorf("failed running `%s` on %s@%s: '%v'", cmd, user, host, err)
}
}
return bout.String(), berr.String(), code, err
}