/
writer.go
84 lines (73 loc) · 1.71 KB
/
writer.go
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package aci
import (
"archive/tar"
"bytes"
"encoding/json"
"io"
"time"
"github.com/appc/spec/schema"
)
// ArchiveWriter writes App Container Images. Users wanting to create an ACI or
// should create an ArchiveWriter and add files to it; the ACI will be written
// to the underlying tar.Writer
type ArchiveWriter interface {
AddFile(hdr *tar.Header, r io.Reader) error
Close() error
}
type imageArchiveWriter struct {
*tar.Writer
am *schema.ImageManifest
}
// NewImageWriter creates a new ArchiveWriter which will generate an App
// Container Image based on the given manifest and write it to the given
// tar.Writer
func NewImageWriter(am schema.ImageManifest, w *tar.Writer) ArchiveWriter {
aw := &imageArchiveWriter{
w,
&am,
}
return aw
}
func (aw *imageArchiveWriter) AddFile(hdr *tar.Header, r io.Reader) error {
err := aw.Writer.WriteHeader(hdr)
if err != nil {
return err
}
if r != nil {
_, err := io.Copy(aw.Writer, r)
if err != nil {
return err
}
}
return nil
}
func (aw *imageArchiveWriter) addFileNow(path string, contents []byte) error {
buf := bytes.NewBuffer(contents)
now := time.Now()
hdr := tar.Header{
Name: path,
Mode: 0644,
Uid: 0,
Gid: 0,
Size: int64(buf.Len()),
ModTime: now,
Typeflag: tar.TypeReg,
Uname: "root",
Gname: "root",
ChangeTime: now,
}
return aw.AddFile(&hdr, buf)
}
func (aw *imageArchiveWriter) addManifest(name string, m json.Marshaler) error {
out, err := m.MarshalJSON()
if err != nil {
return err
}
return aw.addFileNow(name, out)
}
func (aw *imageArchiveWriter) Close() error {
if err := aw.addManifest(ManifestFile, aw.am); err != nil {
return err
}
return aw.Writer.Close()
}