Add --dry-run option.

Changelog.md

@@ -2,3 +2,7 @@
 All notable changes to this project will be documented in this file.  
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).   
 This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+# [0.3.0] - 2022-02-22
+## Added
+- --dry-run option.

cmd/import.go

@@ -13,16 +13,22 @@ import (
 var importCmd = &cobra.Command{
 	Use: "import",
 	Run: func(cmd *cobra.Command, args []string) {
-		os.Exit(runImport())
+		os.Exit(runImport(cmd, args))
 	},
 	Short: "Install command according to gup.conf.",
 }
 
 func init() {
+	importCmd.Flags().BoolP("dry-run", "d", false, "perform the trial update with no changes")
 	rootCmd.AddCommand(importCmd)
 }
 
-func runImport() int {
+func runImport(cmd *cobra.Command, args []string) int {
+	dryRun, err := cmd.Flags().GetBool("dry-run")
+	if err != nil {
+		print.Fatal(fmt.Errorf("%s: %w", "can not parse command line argument", err))
+	}
+
 	if !file.IsFile(config.FilePath()) {
 		print.Fatal(fmt.Errorf("%s is not found", config.FilePath()))
 	}
@@ -36,7 +42,7 @@ func runImport() int {
 		print.Fatal("unable to update package: no package information")
 	}
 
-	pkgs, result := update(pkgs)
+	pkgs, result := update(pkgs, dryRun)
 	for k, v := range result {
 		if v == "Failure" {
 			print.Err(fmt.Errorf("update failure: %s ", k))

cmd/root.go

@@ -20,10 +20,14 @@ If you execute '$ gup', gup gets the package path of all commands
 under $GOPATH/bin and automatically updates commans to the latest
 version.`,
 	Run: func(cmd *cobra.Command, args []string) {
-		os.Exit(gup(args))
+		os.Exit(gup(cmd, args))
 	},
 }
 
+func init() {
+	rootCmd.Flags().BoolP("dry-run", "d", false, "perform the trial update with no changes")
+}
+
 // Execute run gup process.
 func Execute() {
 	if err := rootCmd.Execute(); err != nil {
@@ -33,7 +37,12 @@ func Execute() {
 
 // gup is main sequence.
 // All errors are handled in this function.
-func gup(args []string) int {
+func gup(cmd *cobra.Command, args []string) int {
+	dryRun, err := cmd.Flags().GetBool("dry-run")
+	if err != nil {
+		print.Fatal(fmt.Errorf("%s: %w", "can not parse command line argument", err))
+	}
+
 	if err := goutil.CanUseGoCmd(); err != nil {
 		print.Fatal(fmt.Errorf("%s: %w", "you didn't install golang", err))
 	}
@@ -47,7 +56,7 @@ func gup(args []string) int {
 		print.Fatal("unable to update package: no package information")
 	}
 
-	pkgs, result := update(pkgs)
+	pkgs, result := update(pkgs, dryRun)
 	for k, v := range result {
 		if v == "Failure" {
 			print.Err(fmt.Errorf("update failure: %s ", k))
@@ -64,20 +73,22 @@ func gup(args []string) int {
 	return 0
 }
 
-func update(pkgs []goutil.Package) ([]goutil.Package, map[string]string) {
+func update(pkgs []goutil.Package, dryRun bool) ([]goutil.Package, map[string]string) {
 	tmp := []goutil.Package{}
 	result := map[string]string{}
 	bar := pb.Simple.Start(len(pkgs))
 	bar.SetMaxWidth(80)
 	for _, v := range pkgs {
 		bar.Increment()
-		if v.ImportPath == "" {
-			result[v.ImportPath] = "Failure"
-			continue
-		}
-		if err := goutil.Install(v.ImportPath); err != nil {
-			result[v.ImportPath] = "Failure"
-			continue
+		if !dryRun {
+			if v.ImportPath == "" {
+				result[v.ImportPath] = "Failure"
+				continue
+			}
+			if err := goutil.Install(v.ImportPath); err != nil {
+				result[v.ImportPath] = "Failure"
+				continue
+			}
 		}
 		tmp = append(tmp, goutil.Package{Name: v.Name, ImportPath: v.ImportPath})
 		result[v.ImportPath] = "Success"

internal/cmdinfo/cmdinfo.go

@@ -6,7 +6,7 @@ import (
 
 const (
 	name    = "gup"
-	version = "0.2.1"
+	version = "0.3.0"
 )
 
 // Version return gup command version.