helper/communicator: can be disabled

helper/communicator/config.go

@@ -10,6 +10,7 @@ import (
 // Config is the common configuration that communicators allow within
 // a builder.
 type Config struct {
+	Type          string        `mapstructure:"communicator"`
 	SSHHost       string        `mapstructure:"ssh_host"`
 	SSHPort       int           `mapstructure:"ssh_port"`
 	SSHUsername   string        `mapstructure:"ssh_username"`
@@ -20,6 +21,10 @@ type Config struct {
 }
 
 func (c *Config) Prepare(ctx *interpolate.Context) []error {
+	if c.Type == "" {
+		c.Type = "ssh"
+	}
+
 	if c.SSHPort == 0 {
 		c.SSHPort = 22
 	}

helper/communicator/config_test.go

@@ -0,0 +1,28 @@
+package communicator
+
+import (
+	"testing"
+
+	"github.com/mitchellh/packer/template/interpolate"
+)
+
+func testConfig() *Config {
+	return &Config{
+		SSHUsername: "root",
+	}
+}
+
+func TestConfigType(t *testing.T) {
+	c := testConfig()
+	if err := c.Prepare(testContext(t)); len(err) > 0 {
+		t.Fatalf("bad: %#v", err)
+	}
+
+	if c.Type != "ssh" {
+		t.Fatal("bad: %#v", c)
+	}
+}
+
+func testContext(t *testing.T) *interpolate.Context {
+	return nil
+}

helper/communicator/step_connect.go

@@ -1,6 +1,9 @@
 package communicator
 
 import (
+	"fmt"
+	"log"
+
 	"github.com/mitchellh/multistep"
 	gossh "golang.org/x/crypto/ssh"
 )
@@ -26,14 +29,27 @@ type StepConnect struct {
 }
 
 func (s *StepConnect) Run(state multistep.StateBag) multistep.StepAction {
-	// Eventually we might switch between multiple of these depending
-	// on the communicator type.
-	s.substep = &StepConnectSSH{
-		Config:     s.Config,
-		SSHAddress: s.SSHAddress,
-		SSHConfig:  s.SSHConfig,
+	typeMap := map[string]multistep.Step{
+		"none": nil,
+		"ssh": &StepConnectSSH{
+			Config:     s.Config,
+			SSHAddress: s.SSHAddress,
+			SSHConfig:  s.SSHConfig,
+		},
 	}
 
+	step, ok := typeMap[s.Config.Type]
+	if !ok {
+		state.Put("error", fmt.Errorf("unknown communicator type: %s", s.Config.Type))
+		return multistep.ActionHalt
+	}
+
+	if step == nil {
+		log.Printf("[INFO] communicator disabled, will not connect")
+		return multistep.ActionContinue
+	}
+
+	s.substep = step
 	return s.substep.Run(state)
 }
 

helper/communicator/step_connect_test.go

@@ -0,0 +1,39 @@
+package communicator
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+)
+
+func TestStepConnect_impl(t *testing.T) {
+	var _ multistep.Step = new(StepConnect)
+}
+
+func TestStepConnect_none(t *testing.T) {
+	state := testState(t)
+
+	step := &StepConnect{
+		Config: &Config{
+			Type: "none",
+		},
+	}
+	defer step.Cleanup(state)
+
+	// run the step
+	if action := step.Run(state); action != multistep.ActionContinue {
+		t.Fatalf("bad action: %#v", action)
+	}
+}
+
+func testState(t *testing.T) multistep.StateBag {
+	state := new(multistep.BasicStateBag)
+	state.Put("hook", &packer.MockHook{})
+	state.Put("ui", &packer.BasicUi{
+		Reader: new(bytes.Buffer),
+		Writer: new(bytes.Buffer),
+	})
+	return state
+}