can specify the output format as text or json (#106)

previously we would print the contents of the updated formatted build files to stdout as text. It can be useful for linters to be able to output as json for easier parsing especially when multiple files are updated at once.

.github/workflows/golangci-lint.yml

@@ -18,5 +18,5 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v2
         with:
-          version: v1.55.2
+          version: v1.57.2
 

cmd/puku/puku.go

@@ -30,10 +30,12 @@ var opts = struct {
 		} `positional-args:"true"`
 	} `command:"fmt" description:"Format build files in the provided paths"`
 	Sync struct {
-		Write bool `short:"w" long:"write" description:"Whether to write the files back or just print them to stdout"`
+		Format string `short:"f" long:"format" choice:"json" choice:"text" default:"text" description:"output format when outputting to stdout"` //nolint
+		Write  bool   `short:"w" long:"write" description:"Whether to write the files back or just print them to stdout"`
 	} `command:"sync" description:"Synchronises the go.mod to the third party build file"`
 	Lint struct {
-		Args struct {
+		Format string `short:"f" long:"format" choice:"json" choice:"text" default:"text" description:"output format when outputting to stdout"` //nolint
+		Args   struct {
 			Paths []string `positional-arg-name:"packages" description:"The packages to process"`
 		} `positional-args:"true"`
 	} `command:"lint" description:"Lint build files in the provided paths"`
@@ -44,6 +46,7 @@ var opts = struct {
 	} `command:"watch" description:"Watch build files in the provided paths and update them when needed"`
 	Migrate struct {
 		Write          bool     `short:"w" long:"write" description:"Whether to write the files back or just print them to stdout"`
+		Format         string   `short:"f" long:"format" choice:"json" choice:"text" default:"text" description:"output format when outputting to stdout"` //nolint
 		ThirdPartyDirs []string `long:"third_party_dir" description:"Directories to find go_module rules to migrate"`
 		UpdateGoMod    bool     `short:"g" long:"update_go_mod" description:"Update the go mod with the module(s) being migrated"`
 		Args           struct {
@@ -52,8 +55,9 @@ var opts = struct {
 	} `command:"migrate" description:"Migrates from go_module to go_repo"`
 	Licenses struct {
 		Update struct {
-			Write bool `short:"w" long:"write" description:"Whether to write the files back or just print them to stdout"`
-			Args  struct {
+			Format string `short:"f" long:"format" choice:"json" choice:"text" default:"text" description:"output format when outputting to stdout"` //nolint
+			Write  bool   `short:"w" long:"write" description:"Whether to write the files back or just print them to stdout"`
+			Args   struct {
 				Paths []string `positional-arg-name:"packages" description:"The packages to process"`
 			} `positional-args:"true"`
 		} `command:"update" description:"Updates licences in the given paths"`
@@ -67,30 +71,37 @@ puku is a tool used to generate and update Go targets in build files
 var log = logging.GetLogger()
 
 var funcs = map[string]func(conf *config.Config, plzConf *please.Config, orignalWD string) int{
-	"fmt": func(conf *config.Config, plzConf *please.Config, orignalWD string) int {
+	"fmt": func(_ *config.Config, plzConf *please.Config, orignalWD string) int {
 		paths := work.MustExpandPaths(orignalWD, opts.Fmt.Args.Paths)
-		if err := generate.Update(true, plzConf, paths...); err != nil {
+		if err := generate.Update(plzConf, paths...); err != nil {
 			log.Fatalf("%v", err)
 		}
 		return 0
 	},
-	"sync": func(conf *config.Config, plzConf *please.Config, orignalWD string) int {
+	"sync": func(_ *config.Config, plzConf *please.Config, _ string) int {
 		g := graph.New(plzConf.BuildFileNames())
-		if err := sync.Sync(plzConf, g, opts.Sync.Write); err != nil {
-			log.Fatalf("%v", err)
+		if opts.Sync.Write {
+			if err := sync.Sync(plzConf, g); err != nil {
+				log.Fatalf("%v", err)
+			}
+		} else {
+			if err := sync.SyncToStdout(opts.Sync.Format, plzConf, g); err != nil {
+				log.Fatalf("%v", err)
+			}
 		}
 		return 0
 	},
-	"lint": func(conf *config.Config, plzConf *please.Config, orignalWD string) int {
+	"lint": func(_ *config.Config, plzConf *please.Config, orignalWD string) int {
+
 		paths := work.MustExpandPaths(orignalWD, opts.Lint.Args.Paths)
-		if err := generate.Update(false, plzConf, paths...); err != nil {
+		if err := generate.UpdateToStdout(opts.Lint.Format, plzConf, paths...); err != nil {
 			log.Fatalf("%v", err)
 		}
 		return 0
 	},
-	"watch": func(conf *config.Config, plzConf *please.Config, orignalWD string) int {
+	"watch": func(_ *config.Config, plzConf *please.Config, orignalWD string) int {
 		paths := work.MustExpandPaths(orignalWD, opts.Watch.Args.Paths)
-		if err := generate.Update(true, plzConf, paths...); err != nil {
+		if err := generate.Update(plzConf, paths...); err != nil {
 			log.Fatalf("%v", err)
 		}
 
@@ -105,15 +116,28 @@ var funcs = map[string]func(conf *config.Config, plzConf *please.Config, orignal
 			paths = []string{conf.GetThirdPartyDir()}
 		}
 		paths = work.MustExpandPaths(orignalWD, paths)
-		if err := migrate.Migrate(conf, plzConf, opts.Migrate.Write, opts.Migrate.UpdateGoMod, opts.Migrate.Args.Modules, paths); err != nil {
-			log.Fatalf("%v", err)
+		if opts.Migrate.Write {
+			if err := migrate.Migrate(conf, plzConf, opts.Migrate.UpdateGoMod, opts.Migrate.Args.Modules, paths); err != nil {
+				log.Fatalf("%v", err)
+			}
+		} else {
+			if err := migrate.MigrateToStdout(opts.Migrate.Format, conf, plzConf, opts.Migrate.UpdateGoMod, opts.Migrate.Args.Modules, paths); err != nil {
+				log.Fatalf("%v", err)
+			}
 		}
 		return 0
 	},
-	"update": func(conf *config.Config, plzConf *please.Config, orignalWD string) int {
+	"update": func(_ *config.Config, plzConf *please.Config, orignalWD string) int {
 		paths := work.MustExpandPaths(orignalWD, opts.Licenses.Update.Args.Paths)
-		if err := licences.New(proxy.New(proxy.DefaultURL), graph.New(plzConf.BuildFileNames())).Update(paths, opts.Licenses.Update.Write); err != nil {
-			log.Fatalf("%v", err)
+		l := licences.New(proxy.New(proxy.DefaultURL), graph.New(plzConf.BuildFileNames()))
+		if opts.Licenses.Update.Write {
+			if err := l.Update(paths); err != nil {
+				log.Fatalf("%v", err)
+			}
+		} else {
+			if err := l.UpdateToStdout(opts.Licenses.Update.Format, paths); err != nil {
+				log.Fatalf("%v", err)
+			}
 		}
 		return 0
 	},

generate/generate.go

@@ -70,28 +70,24 @@ func newUpdater(conf *please.Config) *updater {
 	return newUpdaterWithGraph(g, conf)
 }
 
-func Update(write bool, plzConf *please.Config, paths ...string) error {
+func Update(plzConf *please.Config, paths ...string) error {
 	u := newUpdater(plzConf)
-
-	conf, err := config.ReadConfig(".")
-	if err != nil {
+	if err := u.update(paths...); err != nil {
 		return err
 	}
-	u.paths = paths
-
-	if err := u.readAllModules(conf); err != nil {
-		return fmt.Errorf("failed to read third party rules: %v", err)
-	}
+	return u.graph.FormatFiles()
+}
 
-	if err := u.update(conf); err != nil {
+func UpdateToStdout(format string, plzConf *please.Config, paths ...string) error {
+	u := newUpdater(plzConf)
+	if err := u.update(paths...); err != nil {
 		return err
 	}
-
-	return u.graph.FormatFiles(write, os.Stdout)
+	return u.graph.FormatFilesWithWriter(os.Stdout, format)
 }
 
 func (u *updater) readAllModules(conf *config.Config) error {
-	return filepath.WalkDir(conf.GetThirdPartyDir(), func(path string, info fs.DirEntry, err error) error {
+	return filepath.WalkDir(conf.GetThirdPartyDir(), func(path string, info fs.DirEntry, _ error) error {
 		for _, buildFileName := range u.plzConf.BuildFileNames() {
 			if info.Name() == buildFileName {
 				file, err := u.graph.LoadFile(filepath.Dir(path))
@@ -144,7 +140,17 @@ func (u *updater) readModules(file *build.File) error {
 }
 
 // update loops through the provided paths, updating and creating any build rules it finds.
-func (u *updater) update(conf *config.Config) error {
+func (u *updater) update(paths ...string) error {
+	conf, err := config.ReadConfig(".")
+	if err != nil {
+		return err
+	}
+	u.paths = paths
+
+	if err := u.readAllModules(conf); err != nil {
+		return fmt.Errorf("failed to read third party rules: %v", err)
+	}
+
 	for _, path := range u.paths {
 		conf, err := config.ReadConfig(path)
 		if err != nil {

graph/graph.go

@@ -2,6 +2,7 @@ package graph
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"os"
@@ -122,12 +123,24 @@ func (g *Graph) loadFile(path string) (*build.File, error) {
 	return build.ParseBuild(validFilename, nil)
 }
 
-func (g *Graph) FormatFiles(write bool, out io.Writer) error {
+func (g *Graph) FormatFilesWithWriter(out io.Writer, format string) error {
 	if err := g.ensureVisibilities(); err != nil {
 		return err
 	}
 	for _, file := range g.files {
-		if err := saveAndFormatBuildFile(file, write, out); err != nil {
+		if err := writeFormattedBuildFile(file, out, format); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (g *Graph) FormatFiles() error {
+	if err := g.ensureVisibilities(); err != nil {
+		return err
+	}
+	for _, file := range g.files {
+		if err := saveFormattedBuildFile(file); err != nil {
 			return err
 		}
 	}
@@ -218,24 +231,11 @@ func checkVisibility(target labels.Label, visibilities []string) bool {
 	return false
 }
 
-func saveAndFormatBuildFile(buildFile *build.File, write bool, out io.Writer) error {
+func writeFormattedBuildFile(buildFile *build.File, out io.Writer, format string) error {
 	if len(buildFile.Stmt) == 0 {
 		return nil
 	}
-
-	if write {
-		f, err := os.Create(buildFile.Path)
-		if err != nil {
-			return err
-		}
-		defer f.Close()
-
-		_, err = f.Write(build.FormatWithoutRewriting(buildFile))
-		return err
-	}
-
 	target := build.FormatWithoutRewriting(buildFile)
-
 	actual, err := os.ReadFile(buildFile.Path)
 	if err != nil {
 		if !os.IsNotExist(err) {
@@ -245,9 +245,29 @@ func saveAndFormatBuildFile(buildFile *build.File, write bool, out io.Writer) er
 	}
 
 	if !bytes.Equal(target, actual) {
-		_, err := out.Write(target)
+		switch format {
+		case "text":
+			_, err := out.Write(target)
+			return err
+		case "json":
+			e := json.NewEncoder(out)
+			return e.Encode(struct{ Path, Content string }{Path: buildFile.Path, Content: string(target)})
+		}
+	}
+	return nil
+}
+
+func saveFormattedBuildFile(buildFile *build.File) error {
+	if len(buildFile.Stmt) == 0 {
+		return nil
+	}
+
+	f, err := os.Create(buildFile.Path)
+	if err != nil {
 		return err
 	}
+	defer f.Close()
 
-	return nil
+	_, err = f.Write(build.FormatWithoutRewriting(buildFile))
+	return err
 }

graph/graph_test.go

@@ -78,7 +78,7 @@ go_library(
 	})
 
 	bs := new(bytes.Buffer)
-	err = g.FormatFiles(false, bs)
+	err = g.FormatFilesWithWriter(bs, "text")
 	require.NoError(t, err)
 
 	fooT := edit.FindTargetByName(g.files["foo"], "foo")

licences/licences.go

@@ -67,7 +67,21 @@ func getLicences(modPaths []string) (map[string][]string, error) {
 	return ret, nil
 }
 
-func (l *Licenses) Update(paths []string, write bool) error {
+func (l *Licenses) Update(paths []string) error {
+	if err := l.update(paths); err != nil {
+		return err
+	}
+	return l.graph.FormatFiles()
+}
+
+func (l *Licenses) UpdateToStdout(format string, paths []string) error {
+	if err := l.update(paths); err != nil {
+		return err
+	}
+	return l.graph.FormatFilesWithWriter(os.Stdout, format)
+}
+
+func (l *Licenses) update(paths []string) error {
 	var mods []string
 	rules := make(map[string]*build.Rule)
 
@@ -115,8 +129,7 @@ func (l *Licenses) Update(paths []string, write bool) error {
 			rules[mod].SetAttr("licences", edit.NewStringList(license))
 		}
 	}
-
-	return l.graph.FormatFiles(write, os.Stdout)
+	return nil
 }
 
 func (l *Licenses) Get(mod, ver string) ([]string, error) {

licences/licences_test.go

@@ -49,7 +49,7 @@ go_repo(
 		graph: g,
 	}
 
-	err = l.Update([]string{"third_party/go"}, false)
+	err = l.UpdateToStdout("text", []string{"third_party/go"})
 	require.NoError(t, err)
 
 	testify := edit.FindTargetByName(thirdPartFile, "testify")

migrate/migrate.go

@@ -30,18 +30,32 @@ type migrator struct {
 	licences          *licences.Licenses
 }
 
-func Migrate(conf *config.Config, plzConf *please.Config, write, updateGoMod bool, modules, paths []string) error {
+func newMigrator(plzConf *please.Config, conf *config.Config) *migrator {
 	g := graph.New(plzConf.BuildFileNames())
-	m := &migrator{
+	return &migrator{
 		plzConf:           plzConf,
 		graph:             g,
 		thirdPartyFolder:  conf.GetThirdPartyDir(),
 		moduleRules:       map[string]*moduleParts{},
 		licences:          licences.New(proxy.New(proxy.DefaultURL), g),
 		existingRepoRules: map[string]*build.Rule{},
 	}
+}
+
+func Migrate(conf *config.Config, plzConf *please.Config, updateGoMod bool, modules, paths []string) error {
+	m := newMigrator(plzConf, conf)
+	if err := m.migrate(modules, paths, updateGoMod); err != nil {
+		return err
+	}
+	return m.graph.FormatFiles()
+}
 
-	return m.migrate(modules, paths, write, updateGoMod)
+func MigrateToStdout(format string, conf *config.Config, plzConf *please.Config, updateGoMod bool, modules, paths []string) error { //nolint
+	m := newMigrator(plzConf, conf)
+	if err := m.migrate(modules, paths, updateGoMod); err != nil {
+		return err
+	}
+	return m.graph.FormatFilesWithWriter(os.Stdout, format)
 }
 
 // pkgRule represents the rule expr in a pkg
@@ -125,7 +139,7 @@ func binaryAlias(module, thirdPartyDir string, part *pkgRule) (*build.Rule, erro
 	return rule, nil
 }
 
-func (m *migrator) migrate(modules, paths []string, write, updateGoMod bool) error {
+func (m *migrator) migrate(modules, paths []string, updateGoMod bool) error {
 	// Read all the BUILD files under the provided paths to find go_module and go_mod_download rules
 	for _, path := range paths {
 		f, err := m.graph.LoadFile(path)
@@ -144,7 +158,7 @@ func (m *migrator) migrate(modules, paths []string, write, updateGoMod bool) err
 	if err := m.replaceRulesForModules(updateGoMod, modules); err != nil {
 		return err
 	}
-	return m.graph.FormatFiles(write, os.Stdout)
+	return nil
 }
 
 // replaceRulesForModules takes a list of modules and replaces those modules and their dependencies