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package main
import (
"archive/tar"
"bytes"
"encoding/json"
"io"
"os"
"runtime"
"github.com/containers/image/storage"
"github.com/containers/image/types"
sstorage "github.com/containers/storage"
"github.com/containers/storage/pkg/reexec"
digest "github.com/opencontainers/go-digest"
specs "github.com/opencontainers/image-spec/specs-go"
"github.com/opencontainers/image-spec/specs-go/v1"
"github.com/sirupsen/logrus"
"github.com/urfave/cli"
)
func main() {
if reexec.Init() {
return
}
app := cli.NewApp()
app.Name = "bin2img"
app.Usage = "barebones image builder"
app.Version = "0.0.1"
app.Flags = []cli.Flag{
cli.BoolFlag{
Name: "debug",
Usage: "turn on debug logging",
},
cli.StringFlag{
Name: "root",
Usage: "graph root directory",
},
cli.StringFlag{
Name: "runroot",
Usage: "run root directory",
},
cli.StringFlag{
Name: "storage-driver",
Usage: "storage driver",
},
cli.StringSliceFlag{
Name: "storage-opt",
Usage: "storage option",
},
cli.StringFlag{
Name: "image-name",
Usage: "set image name",
Value: "kubernetes/pause",
},
cli.StringFlag{
Name: "source-binary",
Usage: "source binary",
Value: "../../pause/pause",
},
cli.StringFlag{
Name: "image-binary",
Usage: "image binary",
Value: "/pause",
},
}
app.Action = func(c *cli.Context) error {
debug := c.GlobalBool("debug")
rootDir := c.GlobalString("root")
runrootDir := c.GlobalString("runroot")
storageDriver := c.GlobalString("storage-driver")
storageOptions := c.GlobalStringSlice("storage-opt")
imageName := c.GlobalString("image-name")
sourceBinary := c.GlobalString("source-binary")
imageBinary := c.GlobalString("image-binary")
if debug {
logrus.SetLevel(logrus.DebugLevel)
} else {
logrus.SetLevel(logrus.ErrorLevel)
}
if rootDir == "" && runrootDir != "" {
logrus.Errorf("must set --root and --runroot, or neither")
os.Exit(1)
}
if rootDir != "" && runrootDir == "" {
logrus.Errorf("must set --root and --runroot, or neither")
os.Exit(1)
}
storeOptions := sstorage.DefaultStoreOptions
if rootDir != "" && runrootDir != "" {
storeOptions.GraphDriverName = storageDriver
storeOptions.GraphDriverOptions = storageOptions
storeOptions.GraphRoot = rootDir
storeOptions.RunRoot = runrootDir
}
store, err := sstorage.GetStore(storeOptions)
if err != nil {
logrus.Errorf("error opening storage: %v", err)
os.Exit(1)
}
defer func() {
_, _ = store.Shutdown(false)
}()
layerBuffer := &bytes.Buffer{}
binary, err := os.Open(sourceBinary)
if err != nil {
logrus.Errorf("error opening image binary: %v", err)
os.Exit(1)
}
binInfo, err := binary.Stat()
if err != nil {
logrus.Errorf("error statting image binary: %v", err)
os.Exit(1)
}
archive := tar.NewWriter(layerBuffer)
err = archive.WriteHeader(&tar.Header{
Name: imageBinary,
Size: binInfo.Size(),
Mode: 0555,
ModTime: binInfo.ModTime(),
Typeflag: tar.TypeReg,
Uname: "root",
Gname: "root",
})
if err != nil {
logrus.Errorf("error writing archive header: %v", err)
os.Exit(1)
}
_, err = io.Copy(archive, binary)
if err != nil {
logrus.Errorf("error archiving image binary: %v", err)
os.Exit(1)
}
archive.Close()
binary.Close()
layerInfo := types.BlobInfo{
Digest: digest.Canonical.FromBytes(layerBuffer.Bytes()),
Size: int64(layerBuffer.Len()),
}
ref, err := storage.Transport.ParseStoreReference(store, imageName)
if err != nil {
logrus.Errorf("error parsing image name: %v", err)
os.Exit(1)
}
img, err := ref.NewImageDestination(nil)
if err != nil {
logrus.Errorf("error preparing to write image: %v", err)
os.Exit(1)
}
defer img.Close()
layer, err := img.PutBlob(layerBuffer, layerInfo, false)
if err != nil {
logrus.Errorf("error preparing to write image: %v", err)
os.Exit(1)
}
config := &v1.Image{
Architecture: runtime.GOARCH,
OS: runtime.GOOS,
Config: v1.ImageConfig{
User: "root",
Entrypoint: []string{imageBinary},
},
RootFS: v1.RootFS{
Type: "layers",
DiffIDs: []digest.Digest{
layer.Digest,
},
},
}
cbytes, err := json.Marshal(config)
if err != nil {
logrus.Errorf("error encoding configuration: %v", err)
os.Exit(1)
}
configInfo := types.BlobInfo{
Digest: digest.Canonical.FromBytes(cbytes),
Size: int64(len(cbytes)),
}
configInfo, err = img.PutBlob(bytes.NewBuffer(cbytes), configInfo, false)
if err != nil {
logrus.Errorf("error saving configuration: %v", err)
os.Exit(1)
}
manifest := &v1.Manifest{
Versioned: specs.Versioned{
SchemaVersion: 2,
},
Config: v1.Descriptor{
MediaType: v1.MediaTypeImageConfig,
Digest: configInfo.Digest,
Size: int64(len(cbytes)),
},
Layers: []v1.Descriptor{{
MediaType: v1.MediaTypeImageLayer,
Digest: layer.Digest,
Size: layer.Size,
}},
}
mbytes, err := json.Marshal(manifest)
if err != nil {
logrus.Errorf("error encoding manifest: %v", err)
os.Exit(1)
}
err = img.PutManifest(mbytes)
if err != nil {
logrus.Errorf("error saving manifest: %v", err)
os.Exit(1)
}
err = img.Commit()
if err != nil {
logrus.Errorf("error committing image: %v", err)
os.Exit(1)
}
return nil
}
if err := app.Run(os.Args); err != nil {
logrus.Fatal(err)
}
}
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