Interpolate vagrantfile_template on Vagrant post-processor (#9923)

builder/docker/builder.go

@@ -5,6 +5,7 @@ import (
 	"log"
 
 	"github.com/hashicorp/hcl/v2/hcldec"
+	"github.com/hashicorp/packer/builder"
 	"github.com/hashicorp/packer/common"
 	"github.com/hashicorp/packer/helper/communicator"
 	"github.com/hashicorp/packer/helper/multistep"
@@ -29,7 +30,9 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, []string, error) {
 		return nil, warnings, errs
 	}
 
-	return nil, warnings, nil
+	return []string{
+		"ImageSha256",
+	}, warnings, nil
 }
 
 func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (packer.Artifact, error) {
@@ -44,6 +47,16 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 	}
 	log.Printf("[DEBUG] Docker version: %s", version.String())
 
+	// Setup the state bag and initial state for the steps
+	state := new(multistep.BasicStateBag)
+	state.Put("config", &b.config)
+	state.Put("hook", hook)
+	state.Put("ui", ui)
+	generatedData := &builder.GeneratedData{State: state}
+
+	// Setup the driver that will talk to Docker
+	state.Put("driver", driver)
+
 	steps := []multistep.Step{
 		&StepTempDir{},
 		&StepPull{},
@@ -67,7 +80,11 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 		log.Print("[DEBUG] Container will be discarded")
 	} else if b.config.Commit {
 		log.Print("[DEBUG] Container will be committed")
-		steps = append(steps, new(StepCommit))
+		steps = append(steps,
+			new(StepCommit),
+			&StepSetGeneratedData{ // Adds ImageSha256 variable available after StepCommit
+				GeneratedData: generatedData,
+			})
 	} else if b.config.ExportPath != "" {
 		log.Printf("[DEBUG] Container will be exported to %s", b.config.ExportPath)
 		steps = append(steps, new(StepExport))
@@ -75,15 +92,6 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 		return nil, errArtifactNotUsed
 	}
 
-	// Setup the state bag and initial state for the steps
-	state := new(multistep.BasicStateBag)
-	state.Put("config", &b.config)
-	state.Put("hook", hook)
-	state.Put("ui", ui)
-
-	// Setup the driver that will talk to Docker
-	state.Put("driver", driver)
-
 	// Run!
 	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
 	b.runner.Run(ctx, state)

builder/docker/driver.go

@@ -26,6 +26,9 @@ type Driver interface {
 	// for external access.
 	IPAddress(id string) (string, error)
 
+	// Sha256 returns the sha256 id of the image
+	Sha256(id string) (string, error)
+
 	// Login. This will lock the driver from performing another Login
 	// until Logout is called. Therefore, any users MUST call Logout.
 	Login(repo, username, password string) error

builder/docker/driver_docker.go

@@ -159,6 +159,23 @@ func (d *DockerDriver) IPAddress(id string) (string, error) {
 	return strings.TrimSpace(stdout.String()), nil
 }
 
+func (d *DockerDriver) Sha256(id string) (string, error) {
+	var stderr, stdout bytes.Buffer
+	cmd := exec.Command(
+		"docker",
+		"inspect",
+		"--format",
+		"{{ .Id }}",
+		id)
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		return "", fmt.Errorf("Error: %s\n\nStderr: %s", err, stderr.String())
+	}
+
+	return strings.TrimSpace(stdout.String()), nil
+}
+
 func (d *DockerDriver) Login(repo, user, pass string) error {
 	d.l.Lock()
 

builder/docker/driver_mock.go

@@ -28,6 +28,11 @@ type MockDriver struct {
 	IPAddressResult string
 	IPAddressErr    error
 
+	Sha256Called bool
+	Sha256Id     string
+	Sha256Result string
+	Sha256Err    error
+
 	KillCalled bool
 	KillID     string
 	KillError  error
@@ -118,6 +123,12 @@ func (d *MockDriver) IPAddress(id string) (string, error) {
 	return d.IPAddressResult, d.IPAddressErr
 }
 
+func (d *MockDriver) Sha256(id string) (string, error) {
+	d.Sha256Called = true
+	d.Sha256Id = id
+	return d.Sha256Result, d.Sha256Err
+}
+
 func (d *MockDriver) Login(r, u, p string) error {
 	d.LoginCalled = true
 	d.LoginRepo = r

builder/docker/step_set_generated_data.go

@@ -0,0 +1,30 @@
+package docker
+
+import (
+	"context"
+
+	"github.com/hashicorp/packer/builder"
+	"github.com/hashicorp/packer/helper/multistep"
+)
+
+type StepSetGeneratedData struct {
+	GeneratedData *builder.GeneratedData
+}
+
+func (s *StepSetGeneratedData) Run(_ context.Context, state multistep.StateBag) multistep.StepAction {
+	driver := state.Get("driver").(Driver)
+
+	sha256 := "ERR_IMAGE_SHA256_NOT_FOUND"
+	if imageId, ok := state.GetOk("image_id"); ok {
+		s256, err := driver.Sha256(imageId.(string))
+		if err == nil {
+			sha256 = s256
+		}
+	}
+	s.GeneratedData.Put("ImageSha256", sha256)
+	return multistep.ActionContinue
+}
+
+func (s *StepSetGeneratedData) Cleanup(_ multistep.StateBag) {
+	// No cleanup...
+}

builder/docker/step_set_generated_data_test.go

@@ -0,0 +1,51 @@
+package docker
+
+import (
+	"context"
+	"testing"
+
+	"github.com/hashicorp/packer/builder"
+	"github.com/hashicorp/packer/helper/multistep"
+)
+
+func TestStepSetGeneratedData_Run(t *testing.T) {
+	state := testState(t)
+	step := new(StepSetGeneratedData)
+	step.GeneratedData = &builder.GeneratedData{State: state}
+	driver := state.Get("driver").(*MockDriver)
+	driver.Sha256Result = "80B3BB1B1696E73A9B19DEEF92F664F8979F948DF348088B61F9A3477655AF64"
+	state.Put("image_id", "12345")
+
+	if action := step.Run(context.TODO(), state); action != multistep.ActionContinue {
+		t.Fatalf("Should not halt")
+	}
+	if !driver.Sha256Called {
+		t.Fatalf("driver.SHA256 should be called")
+	}
+	if driver.Sha256Id != "12345" {
+		t.Fatalf("driver.SHA256 got wrong image it: %s", driver.Sha256Id)
+	}
+	genData := state.Get("generated_data").(map[string]interface{})
+	imgSha256 := genData["ImageSha256"].(string)
+	if imgSha256 != driver.Sha256Result {
+		t.Fatalf("Expected ImageSha256 to be %s but was %s", driver.Sha256Result, imgSha256)
+	}
+
+	// Image ID not implement
+	state = testState(t)
+	step.GeneratedData = &builder.GeneratedData{State: state}
+	driver = state.Get("driver").(*MockDriver)
+	notImplementedMsg := "ERR_IMAGE_SHA256_NOT_FOUND"
+
+	if action := step.Run(context.TODO(), state); action != multistep.ActionContinue {
+		t.Fatalf("Should not halt")
+	}
+	if driver.Sha256Called {
+		t.Fatalf("driver.SHA256 should not be called")
+	}
+	genData = state.Get("generated_data").(map[string]interface{})
+	imgSha256 = genData["ImageSha256"].(string)
+	if imgSha256 != notImplementedMsg {
+		t.Fatalf("Expected ImageSha256 to be %s but was %s", notImplementedMsg, imgSha256)
+	}
+}

post-processor/vagrant/post-processor.go

@@ -175,7 +175,10 @@ func (p *PostProcessor) PostProcessProvider(name string, provider Provider, ui p
 			return nil, false, err
 		}
 
-		customVagrantfile = string(customBytes)
+		customVagrantfile, err = interpolate.Render(string(customBytes), &config.ctx)
+		if err != nil {
+			return nil, false, err
+		}
 	}
 
 	f, err := os.Create(filepath.Join(dir, "Vagrantfile"))

website/pages/docs/builders/docker.mdx

@@ -215,6 +215,16 @@ You must specify (only) one of `commit`, `discard`, or `export_path`.
 
 @include 'builder/docker/Config-not-required.mdx'
 
+## Build Shared Information Variables
+
+This build shares generated data with provisioners and post-processors via [template engines](/docs/templates/engine)
+for JSON and [contextual variables](/docs/from-1.5/contextual-variables) for HCL2.
+
+The generated variable available for this builder is:
+
+- `ImageSha256` - When committing a container to an image, this will give the image SHA256. Because the image is not available at the provision step,
+this variable is only available for post-processors.
+
 ## Using the Artifact: Export
 
 Once the tar artifact has been generated, you will likely want to import, tag,

website/pages/docs/post-processors/vagrant.mdx

@@ -102,7 +102,8 @@ more details about certain options in following sections.
   `lxc`, `scaleway`, `hyperv`, `parallels`, `aws`, or `google`.
 
 - `vagrantfile_template` (string) - Path to a template to use for the
-  Vagrantfile that is packaged with the box.
+  Vagrantfile that is packaged with the box. This option supports the usage of the [template engine](/docs/templates/engine)
+  for JSON and the [contextual variables](/docs/from-1.5/contextual-variables) for HCL2.
 
 - `vagrantfile_template_generated` (boolean) - By default, Packer will
   exit with an error if the file specified using the