undocker/rootfs/rootfstest/rootfstest.go

137 lines
2.2 KiB
Go

package rootfstest
import (
"archive/tar"
"bytes"
"encoding/json"
"io"
"testing"
"github.com/stretchr/testify/require"
)
type (
Tarrer interface {
Tar(*tar.Writer)
}
Byter interface {
Bytes() []byte
}
Tarball []Tarrer
// Extractable is an empty interface for comparing extracted outputs in tests.
// Using that just to avoid the ugly `interface{}`.
Extractable interface{}
Dir struct {
Name string
Uid int
}
File struct {
Name string
Uid int
Contents Byter
}
Manifest []string
Hardlink struct {
Name string
Uid int
}
dockerManifestJSON []struct {
Layers []string `json:"Layers"`
}
)
func (tb Tarball) Bytes() []byte {
buf := bytes.Buffer{}
tw := tar.NewWriter(&buf)
for _, member := range tb {
member.Tar(tw)
}
tw.Close()
return buf.Bytes()
}
func (d Dir) Tar(tw *tar.Writer) {
hdr := &tar.Header{
Typeflag: tar.TypeDir,
Name: d.Name,
Mode: 0644,
Uid: d.Uid,
}
tw.WriteHeader(hdr)
}
func (f File) Tar(tw *tar.Writer) {
var contentbytes []byte
if f.Contents != nil {
contentbytes = f.Contents.Bytes()
}
hdr := &tar.Header{
Typeflag: tar.TypeReg,
Name: f.Name,
Mode: 0644,
Uid: f.Uid,
Size: int64(len(contentbytes)),
}
tw.WriteHeader(hdr)
tw.Write(contentbytes)
}
func (m Manifest) Tar(tw *tar.Writer) {
b, err := json.Marshal(dockerManifestJSON{{Layers: m}})
if err != nil {
panic("testerr")
}
File{
Name: "manifest.json",
Contents: bytes.NewBuffer(b),
}.Tar(tw)
}
func (h Hardlink) Tar(tw *tar.Writer) {
tw.WriteHeader(&tar.Header{
Typeflag: tar.TypeLink,
Name: h.Name,
Mode: 0644,
Uid: h.Uid,
})
}
func Extract(t *testing.T, r io.Reader) []Extractable {
t.Helper()
ret := []Extractable{}
tr := tar.NewReader(r)
for {
hdr, err := tr.Next()
if err == io.EOF {
break
}
require.NoError(t, err)
var elem Extractable
switch hdr.Typeflag {
case tar.TypeDir:
elem = Dir{Name: hdr.Name, Uid: hdr.Uid}
case tar.TypeLink:
elem = Hardlink{Name: hdr.Name}
case tar.TypeReg:
f := File{Name: hdr.Name, Uid: hdr.Uid}
if hdr.Size > 0 {
var buf bytes.Buffer
io.Copy(&buf, tr)
f.Contents = &buf
}
elem = f
}
ret = append(ret, elem)
}
return ret
}