Async write to files

cmd/ditto.go

@@ -7,6 +7,9 @@ import (
 	"path"
 	"path/filepath"
 
+	"golang.org/x/sync/errgroup"
+
+	"github.com/juanvillacortac/ditto/pkg/generators"
 	"github.com/juanvillacortac/ditto/pkg/program"
 )
 
@@ -22,6 +25,17 @@ var (
 	verbose     = flag.Bool("V", false, "Verbose output")
 )
 
+func writeFile(file generators.OutputFile) error {
+	path := filepath.Dir(file.Filename)
+	if err := os.MkdirAll(path, os.ModePerm); err != nil {
+		return err
+	}
+	if err := os.WriteFile(file.Filename, []byte(file.Body), os.ModePerm); err != nil {
+		return err
+	}
+	return nil
+}
+
 func run() int {
 	flag.Parse()
 
@@ -82,16 +96,18 @@ func run() int {
 		}
 	}
 
+	errg := new(errgroup.Group)
+	errg.SetLimit(len(files))
+
 	for _, f := range files {
-		path := filepath.Dir(f.Filename)
-		if err := os.MkdirAll(path, os.ModePerm); err != nil {
-			fmt.Fprintf(os.Stderr, "%v\n", err)
-			return 1
-		}
-		if err := os.WriteFile(f.Filename, []byte(f.Body), os.ModePerm); err != nil {
-			fmt.Fprintf(os.Stderr, "%v\n", err)
-			return 1
-		}
+		f := f
+		errg.Go(func() error {
+			return writeFile(f)
+		})
+	}
+
+	if err := errg.Wait(); err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
 	}
 	fmt.Println("Done!")
 	return 0

go.mod

@@ -19,4 +19,5 @@ require (
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	golang.org/x/crypto v0.0.0-20220321153916-2c7772ba3064 // indirect
+	golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f // indirect
 )

go.sum

@@ -24,6 +24,8 @@ github.com/yoheimuta/go-protoparser/v4 v4.5.4 h1:0/uEpkzBeSmC591cHIm+M7WIfHaP5FO
 github.com/yoheimuta/go-protoparser/v4 v4.5.4/go.mod h1:AHNNnSWnb0UoL4QgHPiOAg2BniQceFscPI5X/BZNHl8=
 golang.org/x/crypto v0.0.0-20220321153916-2c7772ba3064 h1:S25/rfnfsMVgORT4/J61MJ7rdyseOZOyvLIrZEZ7s6s=
 golang.org/x/crypto v0.0.0-20220321153916-2c7772ba3064/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
+golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f h1:Ax0t5p6N38Ga0dThY21weqDEyz2oklo4IvDkpigvkD8=
+golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=