Fix shutdown_command bug

Fixes the somewhat embarrassing bug where the shutdown_command would be
run on the host rather than the guest.

This commit also rejigs things so that it is easier to do SSH commands
on either the host or the guest

builder/xenserver/common/ssh.go

@@ -20,9 +20,11 @@ func SSHAddress(state multistep.StateBag) (string, error) {
 }
 
 func SSHLocalAddress(state multistep.StateBag) (string, error) {
-	sshLocalPort := state.Get("local_ssh_port").(uint)
+	sshLocalPort, ok := state.Get("local_ssh_port").(uint)
+	if !ok {
+		return "", fmt.Errorf("SSH port forwarding hasn't been set up yet")
+	}
 	conn_str := fmt.Sprintf("%s:%d", "127.0.0.1", sshLocalPort)
-	log.Printf("sshLocalAddress: %s", conn_str)
 	return conn_str, nil
 }
 
@@ -49,24 +51,14 @@ func SSHConfig(state multistep.StateBag) (*gossh.ClientConfig, error) {
 	}, nil
 }
 
-func execute_ssh_cmd(cmd, host, port, username, password string) (stdout string, err error) {
+func doExecuteSSHCmd(cmd, target string, config *gossh.ClientConfig) (stdout string, err error) {
-	// Setup connection config
+	client, err := gossh.Dial("tcp", target, config)
-	config := &gossh.ClientConfig{
-		User: username,
-		Auth: []gossh.AuthMethod{
-			gossh.Password(password),
-		},
-	}
-
-	client, err := gossh.Dial("tcp", host+":"+port, config)
-
 	if err != nil {
 		return "", err
 	}
 
 	//Create session
 	session, err := client.NewSession()
-
 	if err != nil {
 		return "", err
 	}
@@ -82,6 +74,31 @@ func execute_ssh_cmd(cmd, host, port, username, password string) (stdout string,
 	return strings.Trim(b.String(), "\n"), nil
 }
 
+func ExecuteHostSSHCmd(state multistep.StateBag, cmd string) (stdout string, err error) {
+	config := state.Get("commonconfig").(CommonConfig)
+	// Setup connection config
+	sshConfig := &gossh.ClientConfig{
+		User: config.Username,
+		Auth: []gossh.AuthMethod{
+			gossh.Password(config.Password),
+		},
+	}
+	return doExecuteSSHCmd(cmd, config.HostIp+":22", sshConfig)
+}
+
+func ExecuteGuestSSHCmd(state multistep.StateBag, cmd string) (stdout string, err error) {
+	localAddress, err := SSHLocalAddress(state)
+	if err != nil {
+		return
+	}
+	sshConfig, err := SSHConfig(state)
+	if err != nil {
+		return
+	}
+
+	return doExecuteSSHCmd(cmd, localAddress, sshConfig)
+}
+
 func forward(local_conn net.Conn, config *gossh.ClientConfig, server, remote_dest string, remote_port uint) error {
 	defer local_conn.Close()
 

builder/xenserver/common/step_get_vnc_port.go

@@ -10,8 +10,6 @@ import (
 type StepGetVNCPort struct{}
 
 func (self *StepGetVNCPort) Run(state multistep.StateBag) multistep.StepAction {
-
-	config := state.Get("commonconfig").(CommonConfig)
 	ui := state.Get("ui").(packer.Ui)
 
 	ui.Say("Step: forward the instances VNC port over SSH")
@@ -19,7 +17,7 @@ func (self *StepGetVNCPort) Run(state multistep.StateBag) multistep.StepAction {
 	domid := state.Get("domid").(string)
 	cmd := fmt.Sprintf("xenstore-read /local/domain/%s/console/vnc-port", domid)
 
-	remote_vncport, err := execute_ssh_cmd(cmd, config.HostIp, "22", config.Username, config.Password)
+	remote_vncport, err := ExecuteHostSSHCmd(state, cmd)
 	if err != nil {
 		ui.Error(fmt.Sprintf("Unable to get VNC port (is the VM running?): %s", err.Error()))
 		return multistep.ActionHalt

builder/xenserver/common/step_shutdown_and_export.go

@@ -63,7 +63,7 @@ func (StepShutdownAndExport) Run(state multistep.StateBag) multistep.StepAction
 		if config.ShutdownCommand != "" {
 			ui.Say("Executing shutdown command...")
 
-			_, err := execute_ssh_cmd(config.ShutdownCommand, config.HostIp, "22", config.Username, config.Password)
+			_, err := ExecuteGuestSSHCmd(state, config.ShutdownCommand)
 			if err != nil {
 				ui.Error(fmt.Sprintf("Shutdown command failed: %s", err.Error()))
 				return false

builder/xenserver/common/step_start_on_himn.go

@@ -23,7 +23,6 @@ func (self *StepStartOnHIMN) Run(state multistep.StateBag) multistep.StepAction
 
 	ui := state.Get("ui").(packer.Ui)
 	client := state.Get("client").(XenAPIClient)
-	config := state.Get("commonconfig").(CommonConfig)
 
 	ui.Say("Step: Start VM on the Host Internal Mangement Network")
 
@@ -96,7 +95,7 @@ func (self *StepStartOnHIMN) Run(state multistep.StateBag) multistep.StepAction
 	err = InterruptibleWait{
 		Predicate: func() (success bool, err error) {
 			ui.Message(fmt.Sprintf("Attempting to ping interface: %s", ping_cmd))
-			_, err = execute_ssh_cmd(ping_cmd, config.HostIp, "22", config.Username, config.Password)
+			_, err = ExecuteHostSSHCmd(state, ping_cmd)
 
 			switch err.(type) {
 			case nil:

builder/xenserver/common/step_type_boot_command.go

@@ -61,7 +61,7 @@ func (self *StepTypeBootCommand) Run(state multistep.StateBag) multistep.StepAct
 	log.Printf("Connected to the VNC console: %s", c.DesktopName)
 
 	// find local ip
-	envVar, err := execute_ssh_cmd("echo $SSH_CLIENT", config.HostIp, "22", config.Username, config.Password)
+	envVar, err := ExecuteHostSSHCmd(state, "echo $SSH_CLIENT")
 	if err != nil {
 		ui.Error(fmt.Sprintf("Error detecting local IP: %s", err))
 		return multistep.ActionHalt