150 lines
2.8 KiB
Go
150 lines
2.8 KiB
Go
// The code in this file creates a Docker image layer containing the binary of the
|
|
// application itself.
|
|
|
|
package main
|
|
|
|
import (
|
|
"archive/tar"
|
|
"bytes"
|
|
"compress/gzip"
|
|
"crypto/sha256"
|
|
"encoding/json"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"log"
|
|
"os"
|
|
"time"
|
|
)
|
|
|
|
// This function creates a Docker-image digest (i.e. SHA256 hash with
|
|
// algorithm-specification prefix)
|
|
func Digest(b []byte) string {
|
|
hash := sha256.New()
|
|
hash.Write(b)
|
|
|
|
return fmt.Sprintf("sha256:%x", hash.Sum(nil))
|
|
}
|
|
|
|
func GetImageOfCurrentExecutable() Image {
|
|
binary := getCurrentBinary()
|
|
tarArchive := createTarArchive(&map[string][]byte{
|
|
"/main": binary,
|
|
})
|
|
|
|
configJson, configElem := createConfig([]string{Digest(tarArchive)})
|
|
compressed := gzipArchive("Quinistry image", tarArchive)
|
|
manifest := createManifest(&configElem, &compressed)
|
|
manifestJson, _ := json.Marshal(manifest)
|
|
|
|
return Image{
|
|
Layer: compressed,
|
|
LayerDigest: Digest(compressed),
|
|
Manifest: manifestJson,
|
|
ManifestDigest: Digest(manifestJson),
|
|
Config: configJson,
|
|
ConfigDigest: Digest(configJson),
|
|
}
|
|
|
|
}
|
|
|
|
func getCurrentBinary() []byte {
|
|
path, _ := os.Executable()
|
|
file, _ := ioutil.ReadFile(path)
|
|
return file
|
|
}
|
|
|
|
func createTarArchive(files *map[string][]byte) []byte {
|
|
buf := new(bytes.Buffer)
|
|
w := tar.NewWriter(buf)
|
|
|
|
for name, file := range *files {
|
|
hdr := &tar.Header{
|
|
Name: name,
|
|
// Everything is executable \o/
|
|
Mode: 0755,
|
|
Size: int64(len(file)),
|
|
}
|
|
w.WriteHeader(hdr)
|
|
w.Write(file)
|
|
}
|
|
|
|
if err := w.Close(); err != nil {
|
|
log.Fatalln(err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
return buf.Bytes()
|
|
}
|
|
|
|
func gzipArchive(name string, archive []byte) []byte {
|
|
buf := new(bytes.Buffer)
|
|
w := gzip.NewWriter(buf)
|
|
w.Name = name
|
|
w.Write(archive)
|
|
|
|
if err := w.Close(); err != nil {
|
|
log.Fatalln(err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
return buf.Bytes()
|
|
}
|
|
|
|
func createConfig(layerDigests []string) (configJson []byte, elem Element) {
|
|
now := time.Now()
|
|
|
|
imageConfig := &ImageConfig{
|
|
Cmd: []string{"/main"},
|
|
Env: []string{"PATH=/"},
|
|
}
|
|
|
|
rootFs := RootFs{
|
|
DiffIds: layerDigests,
|
|
Type: "layers",
|
|
}
|
|
|
|
history := []History{
|
|
{
|
|
Created: now,
|
|
CreatedBy: "Quinistry magic",
|
|
},
|
|
}
|
|
|
|
config := Config{
|
|
Created: now,
|
|
Author: "tazjin",
|
|
Architecture: "amd64",
|
|
Os: "linux",
|
|
Config: imageConfig,
|
|
RootFs: rootFs,
|
|
History: history,
|
|
}
|
|
|
|
configJson, _ = json.Marshal(config)
|
|
|
|
elem = Element{
|
|
MediaType: ImageConfigMediaType,
|
|
Size: len(configJson),
|
|
Digest: Digest(configJson),
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
func createManifest(config *Element, layer *[]byte) Manifest {
|
|
layers := []Element{
|
|
{
|
|
MediaType: LayerMediaType,
|
|
Size: len(*layer),
|
|
// Layers must contain the digest of the *gzipped* layer.
|
|
Digest: Digest(*layer),
|
|
},
|
|
}
|
|
|
|
return Manifest{
|
|
SchemaVersion: 2,
|
|
MediaType: ManifestMediaType,
|
|
Config: *config,
|
|
Layers: layers,
|
|
}
|
|
}
|