feat(internal/cli): add version command (#2894)

Refactor command initialization, make `version` command as a default
command in each command set.

For #2416

Author: JoeWang1127

cmd/automation/doc.go

@@ -54,5 +54,13 @@ Flags:
 
 	-project string
 	  	Google Cloud Platform project ID (default "cloud-sdk-librarian-prod")
+
+# version
+
+Version prints version information for the automation binary.
+
+Usage:
+
+	automation version
 */
 package main

internal/automation/automation.go

@@ -21,18 +21,16 @@ import (
 )
 
 func newAutomationCommand() *cli.Command {
-	cmd := &cli.Command{
-		Short:     "automation manages Cloud Build resources to run Librarian CLI.",
-		UsageLine: "automation <command> [arguments]",
-		Long:      automationLongHelp,
-		Commands: []*cli.Command{
-			newCmdGenerate(),
-			newCmdPublishRelease(),
-		},
+	commands := []*cli.Command{
+		newCmdGenerate(),
+		newCmdPublishRelease(),
 	}
 
-	cmd.Init()
-	return cmd
+	return cli.NewCommandSet(
+		commands,
+		"automation manages Cloud Build resources to run Librarian CLI.",
+		"automation <command> [arguments]",
+		automationLongHelp)
 }
 
 func newCmdGenerate() *cli.Command {

internal/automation/automation_test.go

@@ -0,0 +1,24 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package automation
+
+import "testing"
+
+func TestAutomationCmdRun(t *testing.T) {
+	cmd := newAutomationCommand()
+	if err := cmd.Run(t.Context(), []string{"version"}); err != nil {
+		t.Fatal(err)
+	}
+}

internal/automation/help.go

@@ -20,5 +20,4 @@ any repository listed in internal/automation/prod/repositories.yaml.`
 	generateLongHelp = `The generate command runs a Cloud Build job to generate Cloud Client Libraries.`
 	publishLongHelp  = `The publish-release command runs a Cloud Build job to create a tag on a merged release pull
 request.`
-	versionLongHelp = "Version prints version information for the automation binary."
 )

internal/cli/cli.go

@@ -53,6 +53,37 @@ type Command struct {
 	Config *config.Config
 }
 
+// NewCommandSet creates and initializes a root *Command object. It automatically appends a "version" subcommand to
+// the list.
+func NewCommandSet(commands []*Command, short, usageLine, long string) *Command {
+	cmd := &Command{
+		Short:     short,
+		UsageLine: usageLine,
+		Long:      long,
+	}
+	verifyCommandDocs(cmd)
+	pkg := strings.Split(cmd.Short, " ")[0]
+	cmd.Commands = append(make([]*Command, 0, len(commands)+1), commands...)
+	cmd.Commands = append(cmd.Commands, newCmdVersion(pkg))
+
+	cmd.Init()
+	return cmd
+}
+
+func newCmdVersion(pkg string) *Command {
+	cmdVersion := &Command{
+		Short:     "version prints the version information",
+		UsageLine: fmt.Sprintf("%s version", pkg),
+		Long:      fmt.Sprintf("Version prints version information for the %s binary.", pkg),
+		Action: func(ctx context.Context, cmd *Command) error {
+			fmt.Println(Version())
+			return nil
+		},
+	}
+	cmdVersion.Init()
+	return cmdVersion
+}
+
 // Run executes the command with the provided arguments.
 func (c *Command) Run(ctx context.Context, args []string) error {
 	cmd, remaining, err := lookupCommand(c, args)
@@ -87,10 +118,7 @@ func (c *Command) Name() string {
 }
 
 func (c *Command) usage(w io.Writer) {
-	if c.Short == "" || c.UsageLine == "" || c.Long == "" {
-		panic(fmt.Sprintf("command %q is missing documentation", c.Name()))
-	}
-
+	verifyCommandDocs(c)
 	fmt.Fprintf(w, "%s\n\n", c.Long)
 	fmt.Fprintf(w, "Usage:\n\n  %s", c.UsageLine)
 	if len(c.Commands) > 0 {
@@ -129,6 +157,12 @@ func hasFlags(fs *flag.FlagSet) bool {
 	return visited
 }
 
+func verifyCommandDocs(c *Command) {
+	if c.Short == "" || c.UsageLine == "" || c.Long == "" {
+		panic(fmt.Sprintf("command %q is missing documentation", c.Name()))
+	}
+}
+
 // lookupCommand looks up the command specified by the given arguments.
 // It returns the command, the remaining arguments, and an error if the command
 // is not found.

internal/cli/cli_test.go

@@ -370,3 +370,10 @@ func TestRun(t *testing.T) {
 		})
 	}
 }
+
+func TestNewCommandSet(t *testing.T) {
+	cmd := NewCommandSet(nil, "short", "usage", "long usageLine")
+	if len(cmd.Commands) != 1 || cmd.Commands[0].Name() != "version" {
+		t.Errorf("NewCommandSet(nil) did not produce a single 'version' command")
+	}
+}

internal/librarian/help.go

@@ -17,8 +17,6 @@ package librarian
 const (
 	librarianLongHelp = "Librarian manages client libraries for Google APIs."
 
-	versionLongHelp = "Version prints version information for the librarian binary."
-
 	releaseLongHelp = "Manages releases of libraries."
 
 	generateLongHelp = `The generate command is the primary tool for all code generation

internal/librarian/librarian.go

@@ -41,41 +41,17 @@ func setupLogger(verbose bool) {
 }
 
 func newLibrarianCommand() *cli.Command {
-	cmdVersion := &cli.Command{
-		Short:     "version prints the version information",
-		UsageLine: "librarian version",
-		Long:      versionLongHelp,
-		Action: func(ctx context.Context, cmd *cli.Command) error {
-			fmt.Println(cli.Version())
-			return nil
-		},
-	}
-	cmdVersion.Init()
-
-	cmdRelease := &cli.Command{
-		Short:     "release manages releases of libraries.",
-		UsageLine: "librarian release <command> [arguments]",
-		Long:      releaseLongHelp,
-		Commands: []*cli.Command{
-			newCmdStage(),
-			newCmdTag(),
-		},
+	commands := []*cli.Command{
+		newCmdGenerate(),
+		newCmdRelease(),
+		newCmdUpdateImage(),
 	}
-	cmdRelease.Init()
 
-	cmd := &cli.Command{
-		Short:     "librarian manages client libraries for Google APIs",
-		UsageLine: "librarian <command> [arguments]",
-		Long:      librarianLongHelp,
-		Commands: []*cli.Command{
-			newCmdGenerate(),
-			cmdRelease,
-			newCmdUpdateImage(),
-			cmdVersion,
-		},
-	}
-	cmd.Init()
-	return cmd
+	return cli.NewCommandSet(
+		commands,
+		"librarian manages client libraries for Google APIs",
+		"librarian <command> [arguments]",
+		librarianLongHelp)
 }
 
 func newCmdGenerate() *cli.Command {
@@ -116,6 +92,20 @@ func newCmdGenerate() *cli.Command {
 	return cmdGenerate
 }
 
+func newCmdRelease() *cli.Command {
+	cmdRelease := &cli.Command{
+		Short:     "release manages releases of libraries.",
+		UsageLine: "librarian release <command> [arguments]",
+		Long:      releaseLongHelp,
+		Commands: []*cli.Command{
+			newCmdStage(),
+			newCmdTag(),
+		},
+	}
+	cmdRelease.Init()
+	return cmdRelease
+}
+
 func newCmdTag() *cli.Command {
 	var verbose bool
 	cmdTag := &cli.Command{