Add a CLI option to change output filenames

Makefile

@@ -43,12 +43,16 @@ test: ## run test
 	go test -race -v ./test
 
 testdata: ## generate test models
-	$(MAKE) -j4 testdata/default testdata/customtypes testdata/single
+	$(MAKE) -j4 testdata/default testdata/with-underscores testdata/customtypes testdata/single
 
 testdata/default:
 	rm -rf test/testmodels/default && mkdir -p test/testmodels/default
 	$(YOBIN) $(SPANNER_PROJECT_NAME) $(SPANNER_INSTANCE_NAME) $(SPANNER_DATABASE_NAME) --package models --out test/testmodels/default/
 
+testdata/with-underscores:
+	rm -rf test/testmodels/underscores && mkdir -p test/testmodels/underscores
+	$(YOBIN) $(SPANNER_PROJECT_NAME) $(SPANNER_INSTANCE_NAME) $(SPANNER_DATABASE_NAME) --package models --with-underscores --out test/testmodels/underscores/
+
 testdata/single:
 	rm -rf test/testmodels/single && mkdir -p test/testmodels/single
 	$(YOBIN) $(SPANNER_PROJECT_NAME) $(SPANNER_INSTANCE_NAME) $(SPANNER_DATABASE_NAME) --out test/testmodels/single/single_file.go --single-file

README.md

@@ -60,6 +60,7 @@ Flags:
       --suffix string                output file suffix (default ".yo.go")
       --tags string                  build tags to add to package header
       --template-path string         user supplied template path
+      --with-underscores             toggle underscores in file names
 ```
 
 ## Generated code

cmd/generate.go

@@ -90,14 +90,15 @@ var (
 			}
 
 			g := generator.NewGenerator(loader, inflector, generator.GeneratorOption{
-				PackageName:       generateOpts.Package,
-				Tags:              generateOpts.Tags,
-				TemplatePath:      generateOpts.TemplatePath,
-				CustomTypePackage: generateOpts.CustomTypePackage,
-				FilenameSuffix:    generateOpts.Suffix,
-				SingleFile:        generateOpts.SingleFile,
-				Filename:          generateOpts.Filename,
-				Path:              generateOpts.Path,
+				PackageName:             generateOpts.Package,
+				Tags:                    generateOpts.Tags,
+				TemplatePath:            generateOpts.TemplatePath,
+				CustomTypePackage:       generateOpts.CustomTypePackage,
+				FilenameSuffix:          generateOpts.Suffix,
+				SingleFile:              generateOpts.SingleFile,
+				Filename:                generateOpts.Filename,
+				FilenameWithUnderscores: generateOpts.FilenameWithUnderscores,
+				Path:                    generateOpts.Path,
 			})
 			if err := g.Generate(tableMap, ixMap); err != nil {
 				return fmt.Errorf("error: %v", err)

cmd/root.go

@@ -89,14 +89,15 @@ var (
 			}
 
 			g := generator.NewGenerator(loader, inflector, generator.GeneratorOption{
-				PackageName:       rootOpts.Package,
-				Tags:              rootOpts.Tags,
-				TemplatePath:      rootOpts.TemplatePath,
-				CustomTypePackage: rootOpts.CustomTypePackage,
-				FilenameSuffix:    rootOpts.Suffix,
-				SingleFile:        rootOpts.SingleFile,
-				Filename:          rootOpts.Filename,
-				Path:              rootOpts.Path,
+				PackageName:             rootOpts.Package,
+				Tags:                    rootOpts.Tags,
+				TemplatePath:            rootOpts.TemplatePath,
+				CustomTypePackage:       rootOpts.CustomTypePackage,
+				FilenameSuffix:          rootOpts.Suffix,
+				SingleFile:              rootOpts.SingleFile,
+				Filename:                rootOpts.Filename,
+				FilenameWithUnderscores: rootOpts.FilenameWithUnderscores,
+				Path:                    rootOpts.Path,
 			})
 			if err := g.Generate(tableMap, ixMap); err != nil {
 				return fmt.Errorf("error: %v", err)
@@ -123,6 +124,7 @@ func setRootOpts(cmd *cobra.Command, opts *internal.ArgType) {
 	cmd.Flags().StringVarP(&opts.Out, "out", "o", "", "output path or file name")
 	cmd.Flags().StringVar(&opts.Suffix, "suffix", defaultSuffix, "output file suffix")
 	cmd.Flags().BoolVar(&opts.SingleFile, "single-file", false, "toggle single file output")
+	cmd.Flags().BoolVar(&opts.FilenameWithUnderscores, "with-underscores", false, "toggle underscores in file names")
 	cmd.Flags().StringVarP(&opts.Package, "package", "p", "", "package name used in generated Go code")
 	cmd.Flags().StringVar(&opts.CustomTypePackage, "custom-type-package", "", "Go package name to use for custom or unknown types")
 	cmd.Flags().StringArrayVar(&opts.TargetTables, "target-tables", nil, "tables to include from the generated Go code")

generator/generator.go

@@ -30,6 +30,7 @@ import (
 	"sort"
 	"strings"
 	"text/template"
+	"unicode"
 
 	"golang.org/x/tools/imports"
 
@@ -45,30 +46,32 @@ type Loader interface {
 }
 
 type GeneratorOption struct {
-	PackageName       string
-	Tags              string
-	TemplatePath      string
-	CustomTypePackage string
-	FilenameSuffix    string
-	SingleFile        bool
-	Filename          string
-	Path              string
+	PackageName             string
+	Tags                    string
+	TemplatePath            string
+	CustomTypePackage       string
+	FilenameSuffix          string
+	SingleFile              bool
+	Filename                string
+	FilenameWithUnderscores bool
+	Path                    string
 }
 
 func NewGenerator(loader Loader, inflector internal.Inflector, opt GeneratorOption) *Generator {
 	return &Generator{
-		loader:             loader,
-		inflector:          inflector,
-		templatePath:       opt.TemplatePath,
-		nameConflictSuffix: "z",
-		packageName:        opt.PackageName,
-		tags:               opt.Tags,
-		customTypePackage:  opt.CustomTypePackage,
-		filenameSuffix:     opt.FilenameSuffix,
-		singleFile:         opt.SingleFile,
-		filename:           opt.Filename,
-		path:               opt.Path,
-		files:              make(map[string]*os.File),
+		loader:                  loader,
+		inflector:               inflector,
+		templatePath:            opt.TemplatePath,
+		nameConflictSuffix:      "z",
+		packageName:             opt.PackageName,
+		tags:                    opt.Tags,
+		customTypePackage:       opt.CustomTypePackage,
+		filenameSuffix:          opt.FilenameSuffix,
+		singleFile:              opt.SingleFile,
+		filename:                opt.Filename,
+		filenameWithUnderscores: opt.FilenameWithUnderscores,
+		path:                    opt.Path,
+		files:                   make(map[string]*os.File),
 	}
 }
 
@@ -83,13 +86,14 @@ type Generator struct {
 	// generated is the generated templates after a run.
 	generated []TBuf
 
-	packageName       string
-	tags              string
-	customTypePackage string
-	filenameSuffix    string
-	singleFile        bool
-	filename          string
-	path              string
+	packageName             string
+	tags                    string
+	customTypePackage       string
+	filenameSuffix          string
+	singleFile              bool
+	filename                string
+	filenameWithUnderscores bool
+	path                    string
 
 	nameConflictSuffix string
 }
@@ -152,9 +156,14 @@ func (g *Generator) Generate(tableMap map[string]*internal.Type, ixMap map[strin
 // the os.OpenFile with the correct parameters depending on the state of args.
 func (g *Generator) getFile(ds *basicDataSet, t *TBuf) (*os.File, error) {
 	// determine filename
-	var filename = strings.ToLower(t.Name) + g.filenameSuffix
-	if g.singleFile {
+	var filename string
+	switch {
+	case g.singleFile:
 		filename = g.filename
+	case g.filenameWithUnderscores:
+		filename = toSnakeCase(t.Name) + g.filenameSuffix
+	default:
+		filename = strings.ToLower(t.Name) + g.filenameSuffix
 	}
 	filename = path.Join(g.path, filename)
 
@@ -174,7 +183,7 @@ func (g *Generator) getFile(ds *basicDataSet, t *TBuf) (*os.File, error) {
 	}
 
 	// open file
-	f, err = os.OpenFile(filename, mode, 0666)
+	f, err = os.OpenFile(filename, mode, 0o666)
 	if err != nil {
 		return nil, err
 	}
@@ -195,6 +204,23 @@ func (g *Generator) getFile(ds *basicDataSet, t *TBuf) (*os.File, error) {
 	return f, nil
 }
 
+func toSnakeCase(s string) string {
+	b := &strings.Builder{}
+	for i, r := range s {
+		if i == 0 {
+			b.WriteRune(unicode.ToLower(r))
+			continue
+		}
+		if unicode.IsUpper(r) {
+			b.WriteRune('_')
+			b.WriteRune(unicode.ToLower(r))
+			continue
+		}
+		b.WriteRune(r)
+	}
+	return b.String()
+}
+
 // importsOptions is the same as x/tools/cmd/goimports options except Fragment.
 var importsOptions = &imports.Options{
 	TabWidth:  8,

internal/argtype.go

@@ -70,8 +70,9 @@ type ArgType struct {
 	// Tags is the list of build tags to add to generated Go files.
 	Tags string
 
-	Path     string
-	Filename string
+	Path                    string
+	Filename                string
+	FilenameWithUnderscores bool
 
 	// DDLFilepath is the filepath of the ddl file.
 	DDLFilepath string

test/integration_test.go

@@ -261,7 +261,7 @@ func TestDefaultCompositePrimaryKey(t *testing.T) {
 	})
 
 	t.Run("ReadByError3", func(t *testing.T) {
-		got, err := models.ReadCompositePrimaryKeysByZYError(ctx, client.Single(), spanner.Key{cpk.Error})
+		got, err := models.ReadCompositePrimaryKeysByYZError(ctx, client.Single(), spanner.Key{cpk.Error})
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}