forked from appc/docker2aci
/
conversion_store.go
126 lines (106 loc) · 3.04 KB
/
conversion_store.go
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// Copyright 2015 The appc Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package docker2aci
import (
"crypto/sha512"
"fmt"
"hash"
"io"
"io/ioutil"
"os"
"github.com/appc/spec/aci"
"github.com/appc/spec/schema"
"github.com/appc/spec/schema/types"
)
const (
hashPrefix = "sha512-"
)
type aciInfo struct {
path string
key string
ImageManifest *schema.ImageManifest
}
// conversionStore is an simple implementation of the acirenderer.ACIRegistry
// interface. It stores the Docker layers converted to ACI so we can take
// advantage of acirenderer to generate a squashed ACI Image.
type conversionStore struct {
acis map[string]*aciInfo
}
func newConversionStore() *conversionStore {
return &conversionStore{acis: make(map[string]*aciInfo)}
}
func (ms *conversionStore) WriteACI(path string) (string, error) {
f, err := os.Open(path)
if err != nil {
return "", err
}
defer f.Close()
cr, err := aci.NewCompressedReader(f)
if err != nil {
return "", err
}
defer cr.Close()
h := sha512.New()
r := io.TeeReader(cr, h)
// read the file so we can get the hash
if _, err := io.Copy(ioutil.Discard, r); err != nil {
return "", fmt.Errorf("error reading ACI: %v", err)
}
im, err := aci.ManifestFromImage(f)
if err != nil {
return "", err
}
key := ms.HashToKey(h)
ms.acis[key] = &aciInfo{path: path, key: key, ImageManifest: im}
return key, nil
}
func (ms *conversionStore) GetImageManifest(key string) (*schema.ImageManifest, error) {
aci, ok := ms.acis[key]
if !ok {
return nil, fmt.Errorf("aci with key: %s not found", key)
}
return aci.ImageManifest, nil
}
func (ms *conversionStore) GetACI(name types.ACIdentifier, labels types.Labels) (string, error) {
for _, aci := range ms.acis {
// we implement this function to comply with the interface so don't
// bother implementing a proper label check
if aci.ImageManifest.Name.String() == name.String() {
return aci.key, nil
}
}
return "", fmt.Errorf("aci not found")
}
func (ms *conversionStore) ReadStream(key string) (io.ReadCloser, error) {
img, ok := ms.acis[key]
if !ok {
return nil, fmt.Errorf("stream for key: %s not found", key)
}
f, err := os.Open(img.path)
if err != nil {
return nil, fmt.Errorf("error opening aci: %s", img.path)
}
tr, err := aci.NewCompressedReader(f)
if err != nil {
return nil, err
}
return tr, nil
}
func (ms *conversionStore) ResolveKey(key string) (string, error) {
return key, nil
}
func (ms *conversionStore) HashToKey(h hash.Hash) string {
s := h.Sum(nil)
return fmt.Sprintf("%s%x", hashPrefix, s)
}