allow content to be pulled for specific platform(s), all platforms

Signed-off-by: Jess Valarezo <valarezo.jessica@gmail.com>

cmd/ctr/commands/content/fetch.go

@@ -101,12 +101,20 @@ func Fetch(ref string, cliContext *cli.Context) (containerd.Image, error) {
 
 	log.G(pctx).WithField("image", ref).Debug("fetching")
 	labels := commands.LabelArgs(cliContext.StringSlice("label"))
-	img, err := client.Pull(pctx, ref,
+	opts := []containerd.RemoteOpt{
 		containerd.WithPullLabels(labels),
 		containerd.WithResolver(resolver),
 		containerd.WithImageHandler(h),
 		containerd.WithSchema1Conversion,
-	)
+	}
+
+	if !cliContext.Bool("all-platforms") {
+		for _, platform := range cliContext.StringSlice("platform") {
+			opts = append(opts, containerd.WithPlatform(platform))
+		}
+	}
+
+	img, err := client.Pull(pctx, ref, opts...)
 	stopProgress()
 	if err != nil {
 		return nil, err

cmd/ctr/commands/images/pull.go

@@ -22,6 +22,7 @@ import (
 	"github.com/containerd/containerd/cmd/ctr/commands"
 	"github.com/containerd/containerd/cmd/ctr/commands/content"
 	"github.com/containerd/containerd/log"
+	"github.com/containerd/containerd/platforms"
 	"github.com/urfave/cli"
 )
 
@@ -38,7 +39,17 @@ command. As part of this process, we do the following:
 2. Prepare the snapshot filesystem with the pulled resources.
 3. Register metadata for the image.
 `,
-	Flags: append(commands.RegistryFlags, append(commands.SnapshotterFlags, commands.LabelFlag)...),
+	Flags: append(append(commands.RegistryFlags, append(commands.SnapshotterFlags, commands.LabelFlag)...),
+		cli.StringSliceFlag{
+			Name:  "platform",
+			Usage: "Pull content from a specific platform",
+			Value: &cli.StringSlice{platforms.Default()},
+		},
+		cli.BoolFlag{
+			Name:  "all-platforms",
+			Usage: "pull content from all platforms",
+		},
+	),
 	Action: func(context *cli.Context) error {
 		var (
 			ref = context.Args().First()