builder/docker: ability to disable pull

builder/docker/config.go

@@ -11,6 +11,7 @@ type Config struct {
 
 	ExportPath string `mapstructure:"export_path"`
 	Image      string
+	Pull       bool
 
 	tpl *packer.ConfigTemplate
 }
@@ -27,6 +28,19 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		return nil, nil, err
 	}
 
+	// Default Pull if it wasn't set
+	hasPull := false
+	for _, k := range md.Keys {
+		if k == "Pull" {
+			hasPull = true
+			break
+		}
+	}
+
+	if !hasPull {
+		c.Pull = true
+	}
+
 	errs := common.CheckUnusedConfig(md)
 
 	templates := map[string]*string{

builder/docker/config_test.go

@@ -23,28 +23,36 @@ func testConfigStruct(t *testing.T) *Config {
 	return c
 }
 
+func testConfigErr(t *testing.T, warns []string, err error) {
+	if len(warns) > 0 {
+		t.Fatalf("bad: %#v", warns)
+	}
+	if err == nil {
+		t.Fatal("should error")
+	}
+}
+
+func testConfigOk(t *testing.T, warns []string, err error) {
+	if len(warns) > 0 {
+		t.Fatalf("bad: %#v", warns)
+	}
+	if err != nil {
+		t.Fatalf("bad: %s", err)
+	}
+}
+
 func TestConfigPrepare_exportPath(t *testing.T) {
 	raw := testConfig()
 
 	// No export path
 	delete(raw, "export_path")
 	_, warns, errs := NewConfig(raw)
-	if len(warns) > 0 {
-		t.Fatalf("bad: %#v", warns)
-	}
-	if errs == nil {
-		t.Fatal("should error")
-	}
+	testConfigErr(t, warns, errs)
 
 	// Good export path
 	raw["export_path"] = "good"
 	_, warns, errs = NewConfig(raw)
-	if len(warns) > 0 {
-		t.Fatalf("bad: %#v", warns)
-	}
-	if errs != nil {
-		t.Fatalf("bad: %s", errs)
-	}
+	testConfigOk(t, warns, errs)
 }
 
 func TestConfigPrepare_image(t *testing.T) {
@@ -53,20 +61,30 @@ func TestConfigPrepare_image(t *testing.T) {
 	// No image
 	delete(raw, "image")
 	_, warns, errs := NewConfig(raw)
-	if len(warns) > 0 {
-		t.Fatalf("bad: %#v", warns)
-	}
-	if errs == nil {
-		t.Fatal("should error")
-	}
+	testConfigErr(t, warns, errs)
 
 	// Good image
 	raw["image"] = "path"
 	_, warns, errs = NewConfig(raw)
-	if len(warns) > 0 {
-		t.Fatalf("bad: %#v", warns)
+	testConfigOk(t, warns, errs)
+}
+
+func TestConfigPrepare_pull(t *testing.T) {
+	raw := testConfig()
+
+	// No pull set
+	delete(raw, "pull")
+	c, warns, errs := NewConfig(raw)
+	testConfigOk(t, warns, errs)
+	if !c.Pull {
+		t.Fatal("should pull by default")
 	}
-	if errs != nil {
-		t.Fatalf("bad: %s", errs)
+
+	// Pull set
+	raw["pull"] = false
+	c, warns, errs = NewConfig(raw)
+	testConfigOk(t, warns, errs)
+	if c.Pull {
+		t.Fatal("should not pull")
 	}
 }

builder/docker/step_pull.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
+	"log"
 )
 
 type StepPull struct{}
@@ -13,6 +14,11 @@ func (s *StepPull) Run(state multistep.StateBag) multistep.StepAction {
 	driver := state.Get("driver").(Driver)
 	ui := state.Get("ui").(packer.Ui)
 
+	if !config.Pull {
+		log.Println("Pull disabled, won't docker pull")
+		return multistep.ActionContinue
+	}
+
 	ui.Say(fmt.Sprintf("Pulling Docker image: %s", config.Image))
 	if err := driver.Pull(config.Image); err != nil {
 		err := fmt.Errorf("Error pulling Docker image: %s", err)

builder/docker/step_pull_test.go

@@ -50,3 +50,24 @@ func TestStepPull_error(t *testing.T) {
 		t.Fatal("should have error")
 	}
 }
+
+func TestStepPull_noPull(t *testing.T) {
+	state := testState(t)
+	step := new(StepPull)
+	defer step.Cleanup(state)
+
+	config := state.Get("config").(*Config)
+	config.Pull = false
+
+	driver := state.Get("driver").(*MockDriver)
+
+	// run the step
+	if action := step.Run(state); action != multistep.ActionContinue {
+		t.Fatalf("bad action: %#v", action)
+	}
+
+	// verify we did the right thing
+	if driver.PullCalled {
+		t.Fatal("shouldn't have pulled")
+	}
+}