Use the *Options structures for command-specific options

Use Destionation: &opts.flag in the flag definition
instead of c.String("flag-name") and the like in the hadler and
matching only by strings.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

cmd/skopeo/copy.go

@@ -32,6 +32,10 @@ func contextsFromGlobalOptions(c *cli.Context) (*types.SystemContext, *types.Sys
 }
 
 type copyOptions struct {
+	additionalTags    cli.StringSlice // For docker-archive: destinations, in addition to the name:tag specified as destination, also add these
+	removeSignatures  bool            // Do not copy signatures from the source image
+	signByFingerprint string          // Sign the image using a GPG key with the specified fingerprint
+	format            optionalString  // Force conversion of the image to a specified format
 }
 
 func copyCmd() cli.Command {
@@ -55,18 +59,21 @@ func copyCmd() cli.Command {
 			cli.StringSliceFlag{
 				Name:  "additional-tag",
 				Usage: "additional tags (supports docker-archive)",
+				Value: &opts.additionalTags, // Surprisingly StringSliceFlag does not support Destination:, but modifies Value: in place.
 			},
 			cli.StringFlag{
 				Name:  "authfile",
 				Usage: "path of the authentication file. Default is ${XDG_RUNTIME_DIR}/containers/auth.json",
 			},
 			cli.BoolFlag{
-				Name:  "remove-signatures",
+				Name:        "remove-signatures",
-				Usage: "Do not copy signatures from SOURCE-IMAGE",
+				Usage:       "Do not copy signatures from SOURCE-IMAGE",
+				Destination: &opts.removeSignatures,
 			},
 			cli.StringFlag{
-				Name:  "sign-by",
+				Name:        "sign-by",
-				Usage: "Sign the image using a GPG key with the specified `FINGERPRINT`",
+				Usage:       "Sign the image using a GPG key with the specified `FINGERPRINT`",
+				Destination: &opts.signByFingerprint,
 			},
 			cli.StringFlag{
 				Name:  "src-creds, screds",
@@ -111,9 +118,10 @@ func copyCmd() cli.Command {
 				Value: "",
 				Usage: "`DIRECTORY` to use to store retrieved blobs (OCI layout destinations only)",
 			},
-			cli.StringFlag{
+			cli.GenericFlag{
 				Name:  "format, f",
 				Usage: "`MANIFEST TYPE` (oci, v2s1, or v2s2) to use when saving image to directory using the 'dir:' transport (default is manifest type of source)",
+				Value: newOptionalStringValue(&opts.format),
 			},
 			cli.BoolFlag{
 				Name:  "dest-compress",
@@ -153,8 +161,6 @@ func (opts *copyOptions) run(c *cli.Context) error {
 	if err != nil {
 		return fmt.Errorf("Invalid destination name %s: %v", c.Args()[1], err)
 	}
-	signBy := c.String("sign-by")
-	removeSignatures := c.Bool("remove-signatures")
 
 	sourceCtx, destinationCtx, err := contextsFromGlobalOptions(c)
 	if err != nil {
@@ -162,8 +168,8 @@ func (opts *copyOptions) run(c *cli.Context) error {
 	}
 
 	var manifestType string
-	if c.IsSet("format") {
+	if opts.format.present {
-		switch c.String("format") {
+		switch opts.format.value {
 		case "oci":
 			manifestType = imgspecv1.MediaTypeImageManifest
 		case "v2s1":
@@ -171,30 +177,28 @@ func (opts *copyOptions) run(c *cli.Context) error {
 		case "v2s2":
 			manifestType = manifest.DockerV2Schema2MediaType
 		default:
-			return fmt.Errorf("unknown format %q. Choose one of the supported formats: 'oci', 'v2s1', or 'v2s2'", c.String("format"))
+			return fmt.Errorf("unknown format %q. Choose one of the supported formats: 'oci', 'v2s1', or 'v2s2'", opts.format.value)
 		}
 	}
 
-	if c.IsSet("additional-tag") {
+	for _, image := range opts.additionalTags {
-		for _, image := range c.StringSlice("additional-tag") {
+		ref, err := reference.ParseNormalizedNamed(image)
-			ref, err := reference.ParseNormalizedNamed(image)
+		if err != nil {
-			if err != nil {
+			return fmt.Errorf("error parsing additional-tag '%s': %v", image, err)
-				return fmt.Errorf("error parsing additional-tag '%s': %v", image, err)
-			}
-			namedTagged, isNamedTagged := ref.(reference.NamedTagged)
-			if !isNamedTagged {
-				return fmt.Errorf("additional-tag '%s' must be a tagged reference", image)
-			}
-			destinationCtx.DockerArchiveAdditionalTags = append(destinationCtx.DockerArchiveAdditionalTags, namedTagged)
 		}
+		namedTagged, isNamedTagged := ref.(reference.NamedTagged)
+		if !isNamedTagged {
+			return fmt.Errorf("additional-tag '%s' must be a tagged reference", image)
+		}
+		destinationCtx.DockerArchiveAdditionalTags = append(destinationCtx.DockerArchiveAdditionalTags, namedTagged)
 	}
 
 	ctx, cancel := commandTimeoutContextFromGlobalOptions(c)
 	defer cancel()
 
 	_, err = copy.Image(ctx, policyContext, destRef, srcRef, &copy.Options{
-		RemoveSignatures:      removeSignatures,
+		RemoveSignatures:      opts.removeSignatures,
-		SignBy:                signBy,
+		SignBy:                opts.signByFingerprint,
 		ReportWriter:          os.Stdout,
 		SourceCtx:             sourceCtx,
 		DestinationCtx:        destinationCtx,

cmd/skopeo/inspect.go

@@ -30,6 +30,7 @@ type inspectOutput struct {
 }
 
 type inspectOptions struct {
+	raw bool // Output the raw manifest instead of parsing information about the image
 }
 
 func inspectCmd() cli.Command {
@@ -61,8 +62,9 @@ func inspectCmd() cli.Command {
 				Usage: "require HTTPS and verify certificates when talking to container registries (defaults to true)",
 			},
 			cli.BoolFlag{
-				Name:  "raw",
+				Name:        "raw",
-				Usage: "output raw manifest",
+				Usage:       "output raw manifest",
+				Destination: &opts.raw,
 			},
 			cli.StringFlag{
 				Name:  "creds",
@@ -93,7 +95,7 @@ func (opts *inspectOptions) run(c *cli.Context) (retErr error) {
 	if err != nil {
 		return err
 	}
-	if c.Bool("raw") {
+	if opts.raw {
 		_, err := c.App.Writer.Write(rawManifest)
 		if err != nil {
 			return fmt.Errorf("Error writing manifest to standard output: %v", err)

cmd/skopeo/signing.go

@@ -11,6 +11,7 @@ import (
 )
 
 type standaloneSignOptions struct {
+	output string // Output file path
 }
 
 func standaloneSignCmd() cli.Command {
@@ -22,16 +23,16 @@ func standaloneSignCmd() cli.Command {
 		Action:    opts.run,
 		Flags: []cli.Flag{
 			cli.StringFlag{
-				Name:  "output, o",
+				Name:        "output, o",
-				Usage: "output the signature to `SIGNATURE`",
+				Usage:       "output the signature to `SIGNATURE`",
+				Destination: &opts.output,
 			},
 		},
 	}
 }
 
 func (opts *standaloneSignOptions) run(c *cli.Context) error {
-	outputFile := c.String("output")
+	if len(c.Args()) != 3 || opts.output == "" {
-	if len(c.Args()) != 3 || outputFile == "" {
 		return errors.New("Usage: skopeo standalone-sign manifest docker-reference key-fingerprint -o signature")
 	}
 	manifestPath := c.Args()[0]
@@ -53,8 +54,8 @@ func (opts *standaloneSignOptions) run(c *cli.Context) error {
 		return fmt.Errorf("Error creating signature: %v", err)
 	}
 
-	if err := ioutil.WriteFile(outputFile, signature, 0644); err != nil {
+	if err := ioutil.WriteFile(opts.output, signature, 0644); err != nil {
-		return fmt.Errorf("Error writing signature to %s: %v", outputFile, err)
+		return fmt.Errorf("Error writing signature to %s: %v", opts.output, err)
 	}
 	return nil
 }