refactor(internal/surfer): migrate to urfave/cli/v3 (#3106)

The surfer package now uses github.com/urfave/cli/v3 instead of the
internal legacycli package. This is the same CLI framework as the
librarian package, and removes a dependency on legacy code.

Author: julieqiu

cmd/surfer/main.go

@@ -25,7 +25,7 @@ import (
 
 func main() {
 	ctx := context.Background()
-	if err := surfer.Run(ctx, os.Args[1:]); err != nil {
+	if err := surfer.Run(ctx, os.Args...); err != nil {
 		log.Fatal(err)
 	}
 }

internal/surfer/surfer/surfer.go

@@ -19,48 +19,51 @@ import (
 	"context"
 	"fmt"
 
-	cli "github.com/googleapis/librarian/internal/legacylibrarian/legacycli"
 	"github.com/googleapis/librarian/internal/surfer/gcloud"
+	"github.com/urfave/cli/v3"
 )
 
 // Run executes the surfer CLI with the given command line arguments.
-func Run(ctx context.Context, args []string) error {
+func Run(ctx context.Context, args ...string) error {
 	cmd := &cli.Command{
-		Short:     "surfer generates gcloud command YAML files",
-		UsageLine: "surfer generate [arguments]",
-		Long:      "surfer generates gcloud command YAML files",
+		Name:        "surfer",
+		Usage:       "generates gcloud command YAML files",
+		UsageText:   "surfer generate [arguments]",
+		Description: "surfer generates gcloud command YAML files",
 		Commands: []*cli.Command{
-			newCmdGenerate(),
+			generateCommand(),
 		},
 	}
-	cmd.Init()
 	return cmd.Run(ctx, args)
 }
 
-func newCmdGenerate() *cli.Command {
-	var (
-		googleapis string
-		out        string
-	)
-
-	cmdGenerate := &cli.Command{
-		Short:     "generate generates gcloud commands",
-		UsageLine: "surfer generate <path to gcloud.yaml> --googleapis <path> [--out <path>]",
-		Long: `generate generates gcloud commands
-
-generate generates gcloud command files from protobuf API specifications,
+func generateCommand() *cli.Command {
+	return &cli.Command{
+		Name:      "generate",
+		Usage:     "generates gcloud commands",
+		UsageText: "surfer generate <path to gcloud.yaml> --googleapis <path> [--out <path>]",
+		Description: `generate generates gcloud command files from protobuf API specifications,
 service config yaml, and gcloud.yaml.`,
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name:  "googleapis",
+				Value: "https://github.com/googleapis/googleapis",
+				Usage: "URL or directory path to googleapis",
+			},
+			&cli.StringFlag{
+				Name:  "out",
+				Value: ".",
+				Usage: "output directory",
+			},
+		},
 		Action: func(ctx context.Context, cmd *cli.Command) error {
-			args := cmd.Flags.Args()
-			if len(args) == 0 {
+			if cmd.Args().Len() == 0 {
 				return fmt.Errorf("path to gcloud.yaml is required")
 			}
-			config := args[0]
+			config := cmd.Args().First()
+			googleapis := cmd.String("googleapis")
+			out := cmd.String("out")
 			return gcloud.Generate(ctx, googleapis, config, out)
 		},
 	}
-	cmdGenerate.Init()
-	cmdGenerate.Flags.StringVar(&googleapis, "googleapis", "https://github.com/googleapis/googleapis", "URL or directory path to googleapis")
-	cmdGenerate.Flags.StringVar(&out, "out", ".", "output directory")
-	return cmdGenerate
 }

internal/surfer/surfer/surfer_test.go

@@ -28,6 +28,7 @@ func TestRun(t *testing.T) {
 		{
 			name: "valid command",
 			args: []string{
+				"surfer",
 				"generate",
 				"../gcloud/testdata/parallelstore/gcloud.yaml",
 				"--out", "../gcloud/testdata/parallelstore/surface",
@@ -36,19 +37,20 @@ func TestRun(t *testing.T) {
 		{
 			name: "invalid gcloud.yaml filepath",
 			args: []string{
+				"surfer",
 				"generate",
 				"invalidpath/gcloud.yaml",
 			},
 			wantErr: true,
 		},
 		{
 			name:    "missing config arg",
-			args:    []string{"generate"},
+			args:    []string{"surfer", "generate"},
 			wantErr: true,
 		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
-			if err := Run(t.Context(), test.args); err != nil {
+			if err := Run(t.Context(), test.args...); err != nil {
 				// TODO(https://github.com/googleapis/librarian/issues/2817):
 				// remove once the generate functionality has been implemented
 				if strings.Contains(err.Error(), "failed to create API model") {