feat: dry run

README.md

@@ -69,6 +69,14 @@ You can also pass *.tf via arguments:
 tfmv -j tfmv.jsonnet foo/aws_s3_bucket.tf foo/aws_instance.tf
 ```
 
+### Dry Run: --dry-run
+
+With `--dry-run`, tfmv outputs logs but doesn't rename blocks.
+
+```sh
+tfmv -j tfmv.jsonnet --dry-run bar/main.tf
+```
+
 ### Change the filename for moved blocks
 
 By default tfmv writes moved blocks to `moved.tf`.

pkg/cli/runner.go

@@ -56,6 +56,7 @@ func (r *Runner) Run(ctx context.Context) error {
 		File:      flg.Jsonnet,
 		Dest:      flg.Moved,
 		Recursive: flg.Recursive,
+		DryRun:    flg.DryRun,
 		Args:      flg.Args,
 	})
 }
@@ -65,10 +66,11 @@ type Flag struct {
 	Moved     string
 	LogLevel  string
 	LogColor  string
+	Args      []string
 	Help      bool
 	Version   bool
 	Recursive bool
-	Args      []string
+	DryRun    bool
 }
 
 func parseFlags(f *Flag) {
@@ -79,6 +81,7 @@ func parseFlags(f *Flag) {
 	flag.BoolVarP(&f.Help, "help", "h", false, "Show help")
 	flag.BoolVarP(&f.Version, "version", "v", false, "Show version")
 	flag.BoolVarP(&f.Recursive, "recursive", "r", false, "If this is set, tfmv finds files recursively")
+	flag.BoolVar(&f.DryRun, "dry-run", false, "Dry Run")
 	flag.Parse()
 	f.Args = flag.Args()
 }
@@ -94,6 +97,7 @@ Options:
 	--version, -v    Show sort-issue-template version
 	--jsonnet, -j    Jsonnet file path
 	--recursive, -r  If this is set, tfmv finds files recursively
+	--dry-run        Dry Run
 	--log-level      Log level
 	--log-color      Log color. "auto", "always", "never" are available
 	--moved, -m      The destination file name. If this is "same", the file is same with the resource`

pkg/controller/controller.go

@@ -22,8 +22,9 @@ func (c *Controller) Init(fs afero.Fs, stdout, stderr io.Writer) {
 type Input struct {
 	File      string
 	Dest      string
-	Recursive bool
 	Args      []string
+	Recursive bool
+	DryRun    bool
 }
 
 const wordResource = "resource"

pkg/controller/run.go

@@ -38,6 +38,7 @@ func (c *Controller) Run(_ context.Context, logE *logrus.Entry, input *Input) er
 	// read *.tf
 	editor := &Editor{
 		stderr: c.stderr,
+		dryRun: input.DryRun,
 	}
 	for _, file := range files {
 		logE := logE.WithField("file", file)
@@ -96,9 +97,14 @@ func (c *Controller) handleBlock(logE *logrus.Entry, editor *Editor, ja ast.Node
 	}
 	movedFile := filepath.Join(filepath.Dir(block.File), fileName)
 	logE.WithField("moved_file", movedFile).Debug("generating a moved block")
-	if err := c.writeMovedBlock(block, dest, movedFile); err != nil {
-		return fmt.Errorf("write a moved block: %w", err)
+	if input.DryRun {
+		logE.WithField("moved_file", movedFile).Info("[DRY RUN] generate a moved block")
+	} else {
+		if err := c.writeMovedBlock(block, dest, movedFile); err != nil {
+			return fmt.Errorf("write a moved block: %w", err)
+		}
 	}
+
 	// rename resources
 	logE.Debug("moving a block")
 	if err := editor.Move(logE, &MoveBlockOpt{