feat(internal/gapicgen): support generating only gapics with genlocal (#3383)

This can speed up generation and removes the edge case where an
error gets returned if there are no new proto stubs to generate
since the last regen.

Author: codyoss

internal/gapicgen/cmd/genbot/generate.go

@@ -67,7 +67,13 @@ func generate(ctx context.Context, githubClient *GithubClient) error {
 	}
 
 	// Regen.
-	changes, err := generator.Generate(ctx, googleapisDir, genprotoDir, gocloudDir, protoDir, "")
+	conf := &generator.Config{
+		GoogleapisDir: googleapisDir,
+		GenprotoDir:   genprotoDir,
+		GapicDir:      gocloudDir,
+		ProtoDir:      protoDir,
+	}
+	changes, err := generator.Generate(ctx, conf)
 	if err != nil {
 		return err
 	}

internal/gapicgen/cmd/genlocal/main.go

@@ -55,6 +55,7 @@ func main() {
 	genprotoDir := flag.String("genproto-dir", filepath.Join(tmpDir, "genproto"), "Directory where sources of googleapis/go-genproto resides. If unset the sources will be cloned to a temporary directory that is not cleaned up.")
 	protoDir := flag.String("proto-dir", filepath.Join(tmpDir, "proto"), "Directory where sources of google/protobuf resides. If unset the sources will be cloned to a temporary directory that is not cleaned up.")
 	gapicToGenerate := flag.String("gapic", "", `Specifies which gapic to generate. The value should be in the form of an import path (Ex: cloud.google.com/go/pubsub/apiv1). The default "" generates all gapics.`)
+	onlyGapics := flag.Bool("only-gapics", false, "Enabling stops regenerating genproto.")
 	verbose := flag.Bool("verbose", false, "Enables verbose logging.")
 	flag.Parse()
 
@@ -71,7 +72,15 @@ func main() {
 	}
 
 	// Regen.
-	changes, err := generator.Generate(ctx, *googleapisDir, *genprotoDir, *gocloudDir, *protoDir, *gapicToGenerate)
+	conf := &generator.Config{
+		GoogleapisDir:     *googleapisDir,
+		GenprotoDir:       *genprotoDir,
+		GapicDir:          *gocloudDir,
+		ProtoDir:          *protoDir,
+		GapicToGenerate:   *gapicToGenerate,
+		OnlyGenerateGapic: *onlyGapics,
+	}
+	changes, err := generator.Generate(ctx, conf)
 	if err != nil {
 		log.Printf("Generator ran (and failed) in %s\n", tmpDir)
 		log.Fatal(err)

internal/gapicgen/generator/gapics.go

@@ -28,31 +28,33 @@ import (
 
 // GapicGenerator is used to regenerate gapic libraries.
 type GapicGenerator struct {
-	googleapisDir  string
-	protoDir       string
-	googleCloudDir string
-	genprotoDir    string
+	googleapisDir   string
+	protoDir        string
+	googleCloudDir  string
+	genprotoDir     string
+	gapicToGenerate string
 }
 
 // NewGapicGenerator creates a GapicGenerator.
-func NewGapicGenerator(googleapisDir, protoDir, googleCloudDir, genprotoDir string) *GapicGenerator {
+func NewGapicGenerator(googleapisDir, protoDir, googleCloudDir, genprotoDir string, gapicToGenerate string) *GapicGenerator {
 	return &GapicGenerator{
-		googleapisDir:  googleapisDir,
-		protoDir:       protoDir,
-		googleCloudDir: googleCloudDir,
-		genprotoDir:    genprotoDir,
+		googleapisDir:   googleapisDir,
+		protoDir:        protoDir,
+		googleCloudDir:  googleCloudDir,
+		genprotoDir:     genprotoDir,
+		gapicToGenerate: gapicToGenerate,
 	}
 }
 
 // Regen generates gapics.
-func (g *GapicGenerator) Regen(ctx context.Context, gapicToGenerate string) error {
+func (g *GapicGenerator) Regen(ctx context.Context) error {
 	log.Println("regenerating gapics")
 	for _, c := range microgenGapicConfigs {
 		// Skip generation if generating all of the gapics and the associated
 		// config has a block on it. Or if generating a single gapic and it does
 		// not match the specified import path.
-		if (c.stopGeneration && gapicToGenerate == "") ||
-			(gapicToGenerate != "" && gapicToGenerate != c.importPath) {
+		if (c.stopGeneration && g.gapicToGenerate == "") ||
+			(g.gapicToGenerate != "" && g.gapicToGenerate != c.importPath) {
 			continue
 		}
 		if err := g.microgen(c); err != nil {

internal/gapicgen/generator/generator.go

@@ -26,23 +26,35 @@ import (
 	"strings"
 )
 
+// Config contains inputs needed to generate sources.
+type Config struct {
+	GoogleapisDir     string
+	GenprotoDir       string
+	GapicDir          string
+	ProtoDir          string
+	GapicToGenerate   string
+	OnlyGenerateGapic bool
+}
+
 // Generate generates genproto and gapics.
-func Generate(ctx context.Context, googleapisDir, genprotoDir, gocloudDir, protoDir string, gapicToGenerate string) ([]*ChangeInfo, error) {
-	protoGenerator := NewGenprotoGenerator(genprotoDir, googleapisDir, protoDir)
-	gapicGenerator := NewGapicGenerator(googleapisDir, protoDir, gocloudDir, genprotoDir)
-	if err := protoGenerator.Regen(ctx); err != nil {
-		return nil, fmt.Errorf("error generating genproto (may need to check logs for more errors): %v", err)
+func Generate(ctx context.Context, conf *Config) ([]*ChangeInfo, error) {
+	if !conf.OnlyGenerateGapic {
+		protoGenerator := NewGenprotoGenerator(conf.GenprotoDir, conf.GoogleapisDir, conf.ProtoDir)
+		if err := protoGenerator.Regen(ctx); err != nil {
+			return nil, fmt.Errorf("error generating genproto (may need to check logs for more errors): %v", err)
+		}
 	}
-	if err := gapicGenerator.Regen(ctx, gapicToGenerate); err != nil {
+	gapicGenerator := NewGapicGenerator(conf.GoogleapisDir, conf.ProtoDir, conf.GapicDir, conf.GenprotoDir, conf.GapicToGenerate)
+	if err := gapicGenerator.Regen(ctx); err != nil {
 		return nil, fmt.Errorf("error generating gapics (may need to check logs for more errors): %v", err)
 	}
 
-	changes, err := gatherChanges(googleapisDir, genprotoDir)
+	changes, err := gatherChanges(conf.GoogleapisDir, conf.GenprotoDir)
 	if err != nil {
 		return nil, fmt.Errorf("error gathering commit info")
 	}
 
-	if err := recordGoogleapisHash(googleapisDir, genprotoDir); err != nil {
+	if err := recordGoogleapisHash(conf.GoogleapisDir, conf.GenprotoDir); err != nil {
 		return nil, err
 	}