/
image.go
119 lines (105 loc) · 2.97 KB
/
image.go
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package cmd
import (
"encoding/json"
"fmt"
"os"
"runtime"
"github.com/nlewo/nix2container/nix"
"github.com/nlewo/nix2container/types"
v1 "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/sirupsen/logrus"
"github.com/spf13/cobra"
)
var fromImageFilename string
var imageCmd = &cobra.Command{
Use: "image OUTPUT-FILENAME CONFIG.JSON LAYERS-1.JSON LAYERS-2.JSON ...",
Short: "Generate an image.json file from a image configuration and layers",
Args: cobra.MinimumNArgs(3),
Run: func(cmd *cobra.Command, args []string) {
err := image(args[0], args[1], fromImageFilename, args[2:])
if err != nil {
fmt.Fprintf(os.Stderr, "%s", err)
os.Exit(1)
}
},
}
var imageFromDirCmd = &cobra.Command{
Use: "image-from-dir OUTPUT-FILENAME DIRECTORY",
Short: "Write an image.json file to OUTPUT-FILENAME from a DIRECTORY populated by the Skopeo dir transport",
Args: cobra.MinimumNArgs(2),
Run: func(cmd *cobra.Command, args []string) {
err := imageFromDir(args[0], args[1])
if err != nil {
fmt.Fprintf(os.Stderr, "%s", err)
os.Exit(1)
}
},
}
func imageFromDir(outputFilename, directory string) error {
image, err := nix.NewImageFromDir(directory)
if err != nil {
return err
}
res, err := json.MarshalIndent(image, "", "\t")
if err != nil {
return err
}
err = os.WriteFile(outputFilename, []byte(res), 0666)
if err != nil {
return err
}
logrus.Infof("Image has been written to %s", outputFilename)
return nil
}
func image(outputFilename, imageConfigPath string, fromImageFilename string, layerPaths []string) error {
var imageConfig v1.ImageConfig
var image types.Image
image.Version = types.ImageVersion
logrus.Infof("Getting image configuration from %s", imageConfigPath)
imageConfigJson, err := os.ReadFile(imageConfigPath)
if err != nil {
return err
}
err = json.Unmarshal(imageConfigJson, &imageConfig)
if err != nil {
return err
}
if fromImageFilename != "" {
fromImage, err := nix.NewImageFromFile(fromImageFilename)
if err != nil {
return err
}
image.Layers = append(image.Layers, fromImage.Layers...)
logrus.Infof("Using base image %s containing %d layers", fromImageFilename, len(fromImage.Layers))
}
image.Arch = runtime.GOARCH
image.ImageConfig = imageConfig
for _, path := range layerPaths {
var layers []types.Layer
layerJson, err := os.ReadFile(path)
if err != nil {
return err
}
err = json.Unmarshal(layerJson, &layers)
if err != nil {
return err
}
logrus.Infof("Adding %d layers from %s", len(layers), path)
image.Layers = append(image.Layers, layers...)
}
res, err := json.MarshalIndent(image, "", "\t")
if err != nil {
return err
}
err = os.WriteFile(outputFilename, []byte(res), 0666)
if err != nil {
return err
}
logrus.Infof("Image has been written to %s", outputFilename)
return nil
}
func init() {
rootCmd.AddCommand(imageCmd)
imageCmd.Flags().StringVarP(&fromImageFilename, "from-image", "", "", "A JSON file describing the base image")
rootCmd.AddCommand(imageFromDirCmd)
}