builder/common: add common StepConnectSSH for builders

builder/common/step_connect_ssh.go

+package common
+
+import (
+	gossh "code.google.com/p/go.crypto/ssh"
+	"errors"
+	"fmt"
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/communicator/ssh"
+	"github.com/mitchellh/packer/packer"
+	"log"
+	"time"
+)
+
+// StepConnectSSH is a multistep Step implementation that waits for SSH
+// to become available. It gets the connection information from a single
+// configuration when creating the step.
+//
+// Uses:
+//   ui packer.Ui
+//
+// Produces:
+//   communicator packer.Communicator
+type StepConnectSSH struct {
+	// SSHAddress is a function that returns the TCP address to connect to
+	// for SSH. This is a function so that you can query information
+	// if necessary for this address.
+	SSHAddress func() (string, error)
+
+	// SSHConfig is a function that returns the proper client configuration
+	// for SSH access.
+	SSHConfig func() (*gossh.ClientConfig, error)
+
+	// SSHWaitTimeout is the total timeout to wait for SSH to become available.
+	SSHWaitTimeout time.Duration
+
+	cancel bool
+	comm   packer.Communicator
+}
+
+func (s *StepConnectSSH) Run(state map[string]interface{}) multistep.StepAction {
+	ui := state["ui"].(packer.Ui)
+
+	var comm packer.Communicator
+	var err error
+
+	waitDone := make(chan bool, 1)
+	go func() {
+		ui.Say("Waiting for SSH to become available...")
+		comm, err = s.waitForSSH()
+		waitDone <- true
+	}()
+
+	log.Printf("Waiting for SSH, up to timeout: %s", s.SSHWaitTimeout)
+	timeout := time.After(s.SSHWaitTimeout)
+WaitLoop:
+	for {
+		// Wait for either SSH to become available, a timeout to occur,
+		// or an interrupt to come through.
+		select {
+		case <-waitDone:
+			if err != nil {
+				ui.Error(fmt.Sprintf("Error waiting for SSH: %s", err))
+				return multistep.ActionHalt
+			}
+
+			ui.Say("Connected to SSH!")
+			s.comm = comm
+			state["communicator"] = comm
+			break WaitLoop
+		case <-timeout:
+			ui.Error("Timeout waiting for SSH.")
+			s.cancel = true
+			return multistep.ActionHalt
+		case <-time.After(1 * time.Second):
+			if _, ok := state[multistep.StateCancelled]; ok {
+				log.Println("Interrupt detected, quitting waiting for SSH.")
+				return multistep.ActionHalt
+			}
+		}
+	}
+
+	return multistep.ActionContinue
+}
+
+func (s *StepConnectSSH) Cleanup(map[string]interface{}) {
+}
+
+func (s *StepConnectSSH) waitForSSH() (packer.Communicator, error) {
+	handshakeAttempts := 0
+
+	var comm packer.Communicator
+	for {
+		time.Sleep(5 * time.Second)
+
+		if s.cancel {
+			log.Println("SSH wait cancelled. Exiting loop.")
+			return nil, errors.New("SSH wait cancelled")
+		}
+
+		// First we request the TCP connection information
+		address, err := s.SSHAddress()
+		if err != nil {
+			log.Printf("Error getting SSH address: %s", err)
+			continue
+		}
+
+		// Retrieve the SSH configuration
+		sshConfig, err := s.SSHConfig()
+		if err != nil {
+			log.Printf("Error getting SSH config: %s", err)
+			continue
+		}
+
+		// Attempt to connect to SSH port
+		connFunc := ssh.ConnectFunc("tcp", address, 5*time.Minute)
+		nc, err := connFunc()
+		if err != nil {
+			log.Printf("TCP connection to SSH ip/port failed: %s", err)
+			continue
+		}
+		nc.Close()
+
+		// Then we attempt to connect via SSH
+		config := &ssh.Config{
+			Connection: connFunc,
+			SSHConfig:  sshConfig,
+		}
+
+		comm, err = ssh.New(config)
+		if err != nil {
+			log.Printf("SSH handshake err: %s", err)
+
+			handshakeAttempts += 1
+			if handshakeAttempts < 10 {
+				// Try to connect via SSH a handful of times
+				continue
+			}
+
+			return nil, err
+		}
+
+		break
+	}
+
+	return comm, nil
+}

builder/common/step_connect_ssh_test.go

+package common
+
+import (
+	"github.com/mitchellh/multistep"
+	"testing"
+)
+
+func TestStepConnectSSH_Impl(t *testing.T) {
+	var raw interface{}
+	raw = new(StepConnectSSH)
+	if _, ok := raw.(multistep.Step); !ok {
+		t.Fatalf("connect ssh should be a step")
+	}
+}