refactor: build cobra commands with constructors

cmd/download.go

@@ -14,32 +14,33 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var opts downloader.Options
+func newDownloadCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:         "download",
+		Short:       "Download tracks from Deezer",
+		Annotations: map[string]string{updateNoticeAnnotation: "true"},
+	}
 
-var downloadCmd = &cobra.Command{
+	opts := &downloader.Options{}
-	Use:         "download",
+	cmd.PersistentFlags().StringVarP(&opts.Quality, "quality", "q", "mp3_320", "download quality [mp3_128, mp3_320, flac]")
-	Short:       "Download tracks from Deezer",
+	cmd.PersistentFlags().DurationVarP(&opts.Timeout, "timeout", "t", 2*time.Minute, "timeout for each download (e.g. 10s, 1m, 2m30s)")
-	Annotations: map[string]string{updateNoticeAnnotation: "true"},
+	cmd.PersistentFlags().BoolVar(&opts.BPM, "bpm", false, "fetch BPM/key and add to file tags")
-}
+	cmd.PersistentFlags().BoolVar(&opts.Genre, "genre", false, "fetch genre and add to file tags")
+	cmd.PersistentFlags().BoolVar(&opts.Strict, "strict", false, "fail the download if the requested quality is unavailable")
 
-func init() {
+	// Every subcommand shares opts: registering the artist-only --limit flag
-	RootCmd.AddCommand(downloadCmd)
+	// stores its default in the shared struct, which Validate requires for all kinds.
-
+	cmd.AddCommand(
-	downloadCmd.PersistentFlags().StringVarP(&opts.Quality, "quality", "q", "mp3_320", "download quality [mp3_128, mp3_320, flac]")
+		newDownloadSubCmd(deezer.KindAlbum, opts),
-	downloadCmd.PersistentFlags().DurationVarP(&opts.Timeout, "timeout", "t", 2*time.Minute, "timeout for each download (e.g. 10s, 1m, 2m30s)")
+		newDownloadSubCmd(deezer.KindPlaylist, opts),
-	downloadCmd.PersistentFlags().BoolVar(&opts.BPM, "bpm", false, "fetch BPM/key and add to file tags")
+		newDownloadSubCmd(deezer.KindArtist, opts),
-	downloadCmd.PersistentFlags().BoolVar(&opts.Genre, "genre", false, "fetch genre and add to file tags")
+		newDownloadSubCmd(deezer.KindTrack, opts),
-	downloadCmd.PersistentFlags().BoolVar(&opts.Strict, "strict", false, "fail the download if the requested quality is unavailable")
-
-	downloadCmd.AddCommand(
-		newDownloadCmd(deezer.KindAlbum),
-		newDownloadCmd(deezer.KindPlaylist),
-		newDownloadCmd(deezer.KindArtist),
-		newDownloadCmd(deezer.KindTrack),
 	)
+
+	return cmd
 }
 
-func newDownloadCmd(kind deezer.Kind) *cobra.Command {
+func newDownloadSubCmd(kind deezer.Kind, opts *downloader.Options) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   fmt.Sprintf("%s <%s_id>", kind, kind),
 		Short: downloadShort(kind),
@@ -61,7 +62,7 @@ func newDownloadCmd(kind deezer.Kind) *cobra.Command {
 			}
 			defer st.Close()
 
-			err = downloader.New(cfg, st, kind).Run(cmd.Context(), opts, args[0])
+			err = downloader.New(cfg, st, kind).Run(cmd.Context(), *opts, args[0])
 			if errors.Is(err, context.Canceled) {
 				return nil
 			}

cmd/login.go

@@ -7,31 +7,29 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var loginCmd = &cobra.Command{
+func newLoginCmd() *cobra.Command {
-	Use:   "login",
+	return &cobra.Command{
-	Short: "Log in to Deezer with your email and password",
+		Use:   "login",
-	Args:  cobra.NoArgs,
+		Short: "Log in to Deezer with your email and password",
-	RunE: func(cmd *cobra.Command, args []string) error {
+		Args:  cobra.NoArgs,
-		if err := auth.CheckGatewayEnv(); err != nil {
+		RunE: func(cmd *cobra.Command, args []string) error {
-			return err
+			if err := auth.CheckGatewayEnv(); err != nil {
-		}
+				return err
+			}
 
-		email, password, err := auth.PromptCredentials()
+			email, password, err := auth.PromptCredentials()
-		if err != nil {
+			if err != nil {
-			return err
+				return err
-		}
+			}
 
-		_, username, err := auth.Login(cmd.Context(), email, password)
+			_, username, err := auth.Login(cmd.Context(), email, password)
-		if err != nil {
+			if err != nil {
-			return err
+				return err
-		}
+			}
 
-		fmt.Printf("Successfully logged in as %s.\n", username)
+			fmt.Printf("Successfully logged in as %s.\n", username)
 
-		return nil
+			return nil
-	},
+		},
-}
+	}
-
-func init() {
-	RootCmd.AddCommand(loginCmd)
 }

cmd/logout.go

@@ -7,21 +7,19 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var logoutCmd = &cobra.Command{
+func newLogoutCmd() *cobra.Command {
-	Use:   "logout",
+	return &cobra.Command{
-	Short: "Remove stored Deezer credentials",
+		Use:   "logout",
-	Args:  cobra.NoArgs,
+		Short: "Remove stored Deezer credentials",
-	RunE: func(cmd *cobra.Command, args []string) error {
+		Args:  cobra.NoArgs,
-		if err := auth.Clear(); err != nil {
+		RunE: func(cmd *cobra.Command, args []string) error {
-			return err
+			if err := auth.Clear(); err != nil {
-		}
+				return err
+			}
 
-		fmt.Println("Successfully logged out.")
+			fmt.Println("Successfully logged out.")
 
-		return nil
+			return nil
-	},
+		},
-}
+	}
-
-func init() {
-	RootCmd.AddCommand(logoutCmd)
 }

cmd/root.go

@@ -14,26 +14,40 @@ import (
 
 const updateNoticeAnnotation = "godeez:update-notice"
 
-var RootCmd = &cobra.Command{
-	Use:          "godeez",
-	Short:        "GoDeez is a tool to download music from Deezer",
-	SilenceUsage: true,
-}
-
 func Execute(ctx context.Context) error {
+	root := NewRootCmd()
+
 	var notice <-chan string
-	if wantsUpdateNotice() {
+	if wantsUpdateNotice(root) {
 		notice = updater.StartCheck(ctx)
 	}
 
-	err := RootCmd.ExecuteContext(ctx)
+	err := root.ExecuteContext(ctx)
 
 	printUpdateNotice(notice)
 
 	return err
 }
 
-func wantsUpdateNotice() bool {
+func NewRootCmd() *cobra.Command {
+	root := &cobra.Command{
+		Use:          "godeez",
+		Short:        "GoDeez is a tool to download music from Deezer",
+		SilenceUsage: true,
+	}
+
+	root.AddCommand(
+		newDownloadCmd(),
+		newLoginCmd(),
+		newLogoutCmd(),
+		newUpdateCmd(),
+		newVersionCmd(),
+	)
+
+	return root
+}
+
+func wantsUpdateNotice(root *cobra.Command) bool {
 	if !term.IsTerminal(int(os.Stderr.Fd())) {
 		return false
 	}
@@ -43,7 +57,7 @@ func wantsUpdateNotice() bool {
 		return false
 	}
 
-	target, _, err := RootCmd.Find(args)
+	target, _, err := root.Find(args)
 	if err != nil || target == nil {
 		return false
 	}

cmd/update.go

@@ -11,26 +11,34 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var updateOpts struct {
+type updateOptions struct {
 	checkOnly bool
 	force     bool
 }
 
-var updateCmd = &cobra.Command{
+func newUpdateCmd() *cobra.Command {
-	Use:   "update",
+	opts := &updateOptions{}
-	Short: "Update GoDeez to the latest version",
+	cmd := &cobra.Command{
-	Args:  cobra.NoArgs,
+		Use:   "update",
-	RunE: func(cmd *cobra.Command, args []string) error {
+		Short: "Update GoDeez to the latest version",
-		err := runUpdate(cmd.Context())
+		Args:  cobra.NoArgs,
-		if errors.Is(err, context.Canceled) {
+		RunE: func(cmd *cobra.Command, args []string) error {
-			return nil
+			err := runUpdate(cmd.Context(), opts)
-		}
+			if errors.Is(err, context.Canceled) {
+				return nil
+			}
 
-		return err
+			return err
-	},
+		},
+	}
+
+	cmd.Flags().BoolVar(&opts.checkOnly, "check", false, "only report whether an update is available")
+	cmd.Flags().BoolVar(&opts.force, "force", false, "reinstall even if already up to date")
+
+	return cmd
 }
 
-func runUpdate(ctx context.Context) error {
+func runUpdate(ctx context.Context, opts *updateOptions) error {
 	if err := updater.CheckUpdatable(); err != nil {
 		return err
 	}
@@ -47,13 +55,13 @@ func runUpdate(ctx context.Context) error {
 	latest := release.Version()
 	fmt.Printf("Current: %s\nLatest:  %s\n", current, latest)
 
-	if !updater.IsNewer(current, latest) && !updateOpts.force {
+	if !updater.IsNewer(current, latest) && !opts.force {
 		fmt.Println("Already up to date.")
 
 		return nil
 	}
 
-	if updateOpts.checkOnly {
+	if opts.checkOnly {
 		fmt.Printf("Run `godeez update` to install %s.\n", latest)
 
 		return nil
@@ -66,10 +74,3 @@ func runUpdate(ctx context.Context) error {
 
 	return nil
 }
-
-func init() {
-	RootCmd.AddCommand(updateCmd)
-
-	updateCmd.Flags().BoolVar(&updateOpts.checkOnly, "check", false, "only report whether an update is available")
-	updateCmd.Flags().BoolVar(&updateOpts.force, "force", false, "reinstall even if already up to date")
-}

cmd/version.go

@@ -8,25 +8,23 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var versionCmd = &cobra.Command{
+func newVersionCmd() *cobra.Command {
-	Use:   "version",
+	return &cobra.Command{
-	Short: "Print the current version of GoDeez",
+		Use:   "version",
-	Args:  cobra.NoArgs,
+		Short: "Print the current version of GoDeez",
-	Run: func(cmd *cobra.Command, args []string) {
+		Args:  cobra.NoArgs,
-		fmt.Printf("godeez %s\n", buildinfo.Version())
+		Run: func(cmd *cobra.Command, args []string) {
+			fmt.Printf("godeez %s\n", buildinfo.Version())
 
-		if commit := buildinfo.Commit(); commit != "" {
+			if commit := buildinfo.Commit(); commit != "" {
-			fmt.Printf("  commit:   %s\n", commit)
+				fmt.Printf("  commit:   %s\n", commit)
-		}
+			}
-		if date := buildinfo.Date(); date != "" {
+			if date := buildinfo.Date(); date != "" {
-			fmt.Printf("  built:    %s\n", date)
+				fmt.Printf("  built:    %s\n", date)
-		}
+			}
 
-		fmt.Printf("  go:       %s\n", runtime.Version())
+			fmt.Printf("  go:       %s\n", runtime.Version())
-		fmt.Printf("  platform: %s/%s\n", runtime.GOOS, runtime.GOARCH)
+			fmt.Printf("  platform: %s/%s\n", runtime.GOOS, runtime.GOARCH)
-	},
+		},
-}
+	}
-
-func init() {
-	RootCmd.AddCommand(versionCmd)
 }