Fix docker-app save on single-file application

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

e2e/commands_test.go

@@ -17,6 +17,20 @@ import (
 	"gotest.tools/icmd"
 )
 
+const (
+	singleFileApp = `version: 0.1.0
+name: helloworld
+description: "hello world app"
+namespace: "foo"
+---
+version: '3.5'
+services:
+  hello-world:
+    image: hello-world
+---
+# This section contains the default values for your application settings.`
+)
+
 // just run a command discarding everything
 func runCommand(exe string, args ...string) {
 	cmd := exec.Command(exe, args...)
@@ -303,6 +317,13 @@ func TestImageBinary(t *testing.T) {
 	assertCommand(t, dockerApp, "inspect", "alice/envvariables.dockerapp:0.1.0")
 }
 
+func TestSaveBinary(t *testing.T) {
+	dir := fs.NewDir(t, "save-prepare-build", fs.WithFile("my.dockerapp", singleFileApp))
+	defer dir.Remove()
+	dockerApp, _ := getDockerAppBinary(t)
+	assertCommand(t, dockerApp, "save", dir.Join("my.dockerapp"))
+}
+
 func TestForkBinary(t *testing.T) {
 	dockerApp, _ := getDockerAppBinary(t)
 	r := startRegistry(t)

internal/packager/registry.go

@@ -35,29 +35,45 @@ func Save(app *types.App, namespace, tag string) (string, error) {
 	if namespace != "" && !strings.HasSuffix(namespace, "/") {
 		namespace += "/"
 	}
+	dir, err := prepareDockerBuildDirectory(app, meta, namespace, tag)
+	if err != nil {
+		return "", err
+	}
+	defer os.RemoveAll(dir)
+	imageName := namespace + internal.AppNameFromDir(app.Name) + internal.AppExtension + ":" + tag
+	args := []string{"build", "-t", imageName, dir}
+	cmd := exec.Command("docker", args...)
+	cmd.Stdout = ioutil.Discard
+	cmd.Stderr = os.Stderr
+	err = cmd.Run()
+	return imageName, err
+}
+
+func prepareDockerBuildDirectory(app *types.App, meta metadata.AppMetadata) (string, error) {
 	dockerfile := fmt.Sprintf(`
 FROM scratch
 LABEL %s=%s
 LABEL maintainers="%v"
 COPY / /
 `, internal.ImageLabel, meta.Name, meta.Maintainers)
-	df := filepath.Join(app.Path, "__Dockerfile-docker-app__")
+	dir, err := ioutil.TempDir("", "app-save")
+	if err != nil {
+		return "", errors.Wrap(err, "cannot create temporary directory")
+	}
+	// Write dockerfile
+	df := filepath.Join(dir, "Dockerfile")
 	if err := ioutil.WriteFile(df, []byte(dockerfile), 0644); err != nil {
-		return "", errors.Wrapf(err, "cannot create file %s", df)
+		return dir, errors.Wrapf(err, "cannot create file %s", df)
 	}
-	defer os.Remove(df)
-	di := filepath.Join(app.Path, ".dockerignore")
-	if err := ioutil.WriteFile(di, []byte("__Dockerfile-docker-app__\n.dockerignore"), 0644); err != nil {
-		return "", errors.Wrapf(err, "cannot create file %s", di)
+	di := filepath.Join(dir, ".dockerignore")
+	if err := ioutil.WriteFile(di, []byte("Dockerfile\n.dockerignore"), 0644); err != nil {
+		return dir, errors.Wrapf(err, "cannot create file %s", di)
 	}
-	defer os.Remove(di)
-	imageName := namespace + internal.AppNameFromDir(app.Name) + internal.AppExtension + ":" + tag
-	args := []string{"build", "-t", imageName, "-f", df, app.Path}
-	cmd := exec.Command("docker", args...)
-	cmd.Stdout = ioutil.Discard
-	cmd.Stderr = os.Stderr
-	err = cmd.Run()
-	return imageName, err
+	// Write app content
+	if err := app.Extract(dir); err != nil {
+		return dir, errors.Wrap(err, "cannot extract app")
+	}
+	return dir, nil
 }
 
 // Load loads an app from docker

types/types.go

@@ -39,6 +39,20 @@ func (a *App) Metadata() []byte {
 	return a.metadataContent
 }
 
+// Extract writes the app in the specified folder
+func (a *App) Extract(path string) error {
+	if err := ioutil.WriteFile(filepath.Join(path, internal.MetadataFileName), a.Metadata(), 0644); err != nil {
+		return err
+	}
+	if err := ioutil.WriteFile(filepath.Join(path, internal.ComposeFileName), a.Composes()[0], 0644); err != nil {
+		return err
+	}
+	if err := ioutil.WriteFile(filepath.Join(path, internal.SettingsFileName), a.Settings()[0], 0644); err != nil {
+		return err
+	}
+	return nil
+}
+
 func noop() {}
 
 // NewApp creates a new docker app with the specified path and struct modifiers