Introduce image size command

Add command to determine the image size.

internal/cmd/image_size.go

@@ -0,0 +1,110 @@
+// Copyright © 2024 The Homeport Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package cmd
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/homeport/forklift/pkg/misc"
+	"github.com/spf13/cobra"
+)
+
+type imageSizeCmdOpts struct {
+	humanReadable bool
+	uncompressed  bool
+}
+
+var imageSizeCmdSettings imageSizeCmdOpts
+
+var imageSizeCmd = &cobra.Command{
+	Use:          "size <image-reference>",
+	Args:         cobra.MinimumNArgs(1),
+	Short:        "Determine image size",
+	Long:         `Determine the image size of a given image`,
+	SilenceUsage: true,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		ref, err := name.ParseReference(args[0])
+		if err != nil {
+			return err
+		}
+
+		image, err := misc.LoadImage(cmd.Context(), ref)
+		if err != nil {
+			return err
+		}
+
+		size, err := image.Size()
+		if err != nil {
+			return err
+		}
+
+		layers, err := misc.Layers(image)
+		if err != nil {
+			return err
+		}
+
+		for _, layer := range layers {
+			if layer.Layer == nil {
+				continue
+			}
+
+			if imageSizeCmdSettings.uncompressed {
+				r, err := layer.Uncompressed()
+				if err != nil {
+					return err
+				}
+
+				written, err := io.Copy(io.Discard, r)
+				if err != nil {
+					return err
+				}
+
+				size += written
+
+			} else {
+				layerSize, err := layer.Size()
+				if err != nil {
+					return err
+				}
+
+				size += layerSize
+			}
+		}
+
+		if imageSizeCmdSettings.humanReadable {
+			fmt.Println(humanReadableSize(size))
+
+		} else {
+			fmt.Printf("%d\n", size)
+		}
+
+		return nil
+	},
+}
+
+func init() {
+	imageCmd.AddCommand(imageSizeCmd)
+
+	imageSizeCmd.Flags().BoolVarP(&imageSizeCmdSettings.humanReadable, "human-readable", "H", false, "Show sizes in human readable ranges")
+	imageSizeCmd.Flags().BoolVarP(&imageSizeCmdSettings.uncompressed, "uncompressed", "u", false, "Determine the uncompressed image size")
+}