feat: add support for completer in snaps (#1055)

* feat: add support for completer in snaps

* test: add completer test

internal/pipe/snapcraft/snapcraft.go

@@ -50,9 +50,10 @@ type Metadata struct {
 
 // AppMetadata for the binaries that will be in the snap package
 type AppMetadata struct {
-	Command string
-	Plugs   []string `yaml:",omitempty"`
-	Daemon  string   `yaml:",omitempty"`
+	Command   string
+	Plugs     []string `yaml:",omitempty"`
+	Daemon    string   `yaml:",omitempty"`
+	Completer string   `yaml:",omitempty"`
 }
 
 const defaultNameTemplate = "{{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}{{ if .Arm }}v{{ .Arm }}{{ end }}"
@@ -199,13 +200,18 @@ func create(ctx *context.Context, snap config.Snapcraft, arch string, binaries [
 		appMetadata := AppMetadata{
 			Command: name,
 		}
+		completerPath := ""
 		if configAppMetadata, ok := snap.Apps[name]; ok {
 			appMetadata.Plugs = configAppMetadata.Plugs
 			appMetadata.Daemon = configAppMetadata.Daemon
 			appMetadata.Command = strings.TrimSpace(strings.Join([]string{
 				appMetadata.Command,
 				configAppMetadata.Args,
 			}, " "))
+			if configAppMetadata.Completer != "" {
+				completerPath = configAppMetadata.Completer
+				appMetadata.Completer = filepath.Base(completerPath)
+			}
 		}
 		metadata.Apps[name] = appMetadata
 		metadata.Plugs = snap.Plugs
@@ -220,6 +226,19 @@ func create(ctx *context.Context, snap config.Snapcraft, arch string, binaries [
 		if err := os.Chmod(destBinaryPath, 0555); err != nil {
 			return errors.Wrap(err, "failed to change binary permissions")
 		}
+
+		if completerPath != "" {
+			destCompleterPath := filepath.Join(primeDir, filepath.Base(completerPath))
+			log.WithField("src", completerPath).
+				WithField("dst", destCompleterPath).
+				Debug("linking")
+			if err := os.Link(completerPath, destCompleterPath); err != nil {
+				return errors.Wrap(err, "failed to link completer")
+			}
+			if err := os.Chmod(destCompleterPath, 0444); err != nil {
+				return errors.Wrap(err, "failed to change completer permissions")
+			}
+		}
 	}
 
 	if _, ok := metadata.Apps[metadata.Name]; !ok {

internal/pipe/snapcraft/snapcraft_test.go

@@ -245,7 +245,6 @@ func TestNoSnapcraftInPath(t *testing.T) {
 	assert.EqualError(t, Pipe{}.Run(ctx), ErrNoSnapcraft.Error())
 }
 
-
 func TestRunNoArguments(t *testing.T) {
 	folder, err := ioutil.TempDir("", "archivetest")
 	assert.NoError(t, err)
@@ -282,6 +281,44 @@ func TestRunNoArguments(t *testing.T) {
 	assert.Equal(t, "mybin", metadata.Apps["mybin"].Command)
 }
 
+func TestCompleter(t *testing.T) {
+	folder, err := ioutil.TempDir("", "archivetest")
+	require.NoError(t, err)
+	var dist = filepath.Join(folder, "dist")
+	require.NoError(t, os.Mkdir(dist, 0755))
+	require.NoError(t, err)
+	var ctx = context.New(config.Project{
+		ProjectName: "testprojectname",
+		Dist:        dist,
+		Snapcrafts: []config.Snapcraft{
+			{
+				NameTemplate: "foo_{{.Arch}}",
+				Summary:      "test summary",
+				Description:  "test description",
+				Apps: map[string]config.SnapcraftAppMetadata{
+					"mybin": {
+						Daemon:    "simple",
+						Args:      "",
+						Completer: "mybin-completer.bash",
+					},
+				},
+				Builds: []string{"foo"},
+			},
+		},
+	})
+	ctx.Git.CurrentTag = "v1.2.3"
+	ctx.Version = "v1.2.3"
+	addBinaries(t, ctx, "foo", dist, "mybin")
+	require.NoError(t, Pipe{}.Run(ctx))
+	yamlFile, err := ioutil.ReadFile(filepath.Join(dist, "foo_amd64", "prime", "meta", "snap.yaml"))
+	require.NoError(t, err)
+	var metadata Metadata
+	err = yaml.Unmarshal(yamlFile, &metadata)
+	require.NoError(t, err)
+	assert.Equal(t, "mybin", metadata.Apps["mybin"].Command)
+	assert.Equal(t, "mybin-completer.bash", metadata.Apps["mybin"].Completer)
+}
+
 func TestDefault(t *testing.T) {
 	var ctx = context.New(config.Project{
 		Builds: []config.Build{

pkg/config/config.go

@@ -215,9 +215,10 @@ type Sign struct {
 
 // SnapcraftAppMetadata for the binaries that will be in the snap package
 type SnapcraftAppMetadata struct {
-	Plugs  []string
-	Daemon string
-	Args   string
+	Plugs     []string
+	Daemon    string
+	Args      string
+	Completer string `yaml:",omitempty"`
 }
 
 // Snapcraft config

www/content/snapcraft.md

@@ -112,6 +112,11 @@ snapcrafts:
         # If you any to pass args to your binary, you can add them with the
         # args option.
         args: --foo
+
+        # Bash completion snippet. More information about completion here:
+        # https://docs.snapcraft.io/tab-completion-for-snaps.
+        completer: drumroll-completion.bash
+
     # Allows plugs to be configured. Plugs like system-files and personal-files
     # require this.
     # Default is empty.