forked from google/go-containerregistry
/
image.go
246 lines (213 loc) · 6.69 KB
/
image.go
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// Copyright 2018 Google LLC All Rights Reserved.
//
// 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 remote
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"sync"
"github.com/aaron-prindle/go-containerregistry/pkg/authn"
"github.com/aaron-prindle/go-containerregistry/pkg/name"
v1 "github.com/aaron-prindle/go-containerregistry/pkg/v1"
"github.com/aaron-prindle/go-containerregistry/pkg/v1/partial"
"github.com/aaron-prindle/go-containerregistry/pkg/v1/remote/transport"
"github.com/aaron-prindle/go-containerregistry/pkg/v1/types"
"github.com/aaron-prindle/go-containerregistry/pkg/v1/v1util"
)
// remoteImage accesses an image from a remote registry
type remoteImage struct {
ref name.Reference
client *http.Client
manifestLock sync.Mutex // Protects manifest
manifest []byte
configLock sync.Mutex // Protects config
config []byte
}
type ImageOption func(*imageOpener) error
var _ partial.CompressedImageCore = (*remoteImage)(nil)
type imageOpener struct {
auth authn.Authenticator
transport http.RoundTripper
ref name.Reference
client *http.Client
}
func (i *imageOpener) Open() (v1.Image, error) {
tr, err := transport.New(i.ref.Context().Registry, i.auth, i.transport, []string{i.ref.Scope(transport.PullScope)})
if err != nil {
return nil, err
}
ri := &remoteImage{
ref: i.ref,
client: &http.Client{Transport: tr},
}
imgCore, err := partial.CompressedToImage(ri)
if err != nil {
return imgCore, err
}
// Wrap the v1.Layers returned by this v1.Image in a hint for downstream
// remote.Write calls to facilitate cross-repo "mounting".
return &mountableImage{
Image: imgCore,
Reference: i.ref,
}, nil
}
// Image provides access to a remote image reference, applying functional options
// to the underlying imageOpener before resolving the reference into a v1.Image.
func Image(ref name.Reference, options ...ImageOption) (v1.Image, error) {
img := &imageOpener{
auth: authn.Anonymous,
transport: http.DefaultTransport,
ref: ref,
}
for _, option := range options {
if err := option(img); err != nil {
return nil, err
}
}
return img.Open()
}
func (r *remoteImage) url(resource, identifier string) url.URL {
return url.URL{
Scheme: r.ref.Context().Registry.Scheme(),
Host: r.ref.Context().RegistryStr(),
Path: fmt.Sprintf("/v2/%s/%s/%s", r.ref.Context().RepositoryStr(), resource, identifier),
}
}
func (r *remoteImage) MediaType() (types.MediaType, error) {
// TODO(jonjohnsonjr): Determine this based on response.
return types.DockerManifestSchema2, nil
}
// TODO(jonjohnsonjr): Handle manifest lists.
func (r *remoteImage) RawManifest() ([]byte, error) {
r.manifestLock.Lock()
defer r.manifestLock.Unlock()
if r.manifest != nil {
return r.manifest, nil
}
u := r.url("manifests", r.ref.Identifier())
req, err := http.NewRequest(http.MethodGet, u.String(), nil)
if err != nil {
return nil, err
}
// TODO(jonjohnsonjr): Accept OCI manifest, manifest list, and image index.
req.Header.Set("Accept", string(types.DockerManifestSchema2))
resp, err := r.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if err := CheckError(resp, http.StatusOK); err != nil {
return nil, err
}
manifest, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
digest, _, err := v1.SHA256(bytes.NewReader(manifest))
if err != nil {
return nil, err
}
// Validate the digest matches what we asked for, if pulling by digest.
if dgst, ok := r.ref.(name.Digest); ok {
if digest.String() != dgst.DigestStr() {
return nil, fmt.Errorf("manifest digest: %q does not match requested digest: %q for %q", digest, dgst.DigestStr(), r.ref)
}
} else {
// Do nothing for tags; I give up.
//
// We'd like to validate that the "Docker-Content-Digest" header matches what is returned by the registry,
// but so many registries implement this incorrectly that it's not worth checking.
//
// For reference:
// https://github.com/docker/distribution/issues/2395
// https://github.com/GoogleContainerTools/kaniko/issues/298
}
r.manifest = manifest
return r.manifest, nil
}
func (r *remoteImage) RawConfigFile() ([]byte, error) {
r.configLock.Lock()
defer r.configLock.Unlock()
if r.config != nil {
return r.config, nil
}
m, err := partial.Manifest(r)
if err != nil {
return nil, err
}
cl, err := r.LayerByDigest(m.Config.Digest)
if err != nil {
return nil, err
}
body, err := cl.Compressed()
if err != nil {
return nil, err
}
defer body.Close()
r.config, err = ioutil.ReadAll(body)
if err != nil {
return nil, err
}
return r.config, nil
}
// remoteLayer implements partial.CompressedLayer
type remoteLayer struct {
ri *remoteImage
digest v1.Hash
}
// Digest implements partial.CompressedLayer
func (rl *remoteLayer) Digest() (v1.Hash, error) {
return rl.digest, nil
}
// Compressed implements partial.CompressedLayer
func (rl *remoteLayer) Compressed() (io.ReadCloser, error) {
u := rl.ri.url("blobs", rl.digest.String())
resp, err := rl.ri.client.Get(u.String())
if err != nil {
return nil, err
}
if err := CheckError(resp, http.StatusOK); err != nil {
resp.Body.Close()
return nil, err
}
return v1util.VerifyReadCloser(resp.Body, rl.digest)
}
// Manifest implements partial.WithManifest so that we can use partial.BlobSize below.
func (rl *remoteLayer) Manifest() (*v1.Manifest, error) {
return partial.Manifest(rl.ri)
}
// Size implements partial.CompressedLayer
func (rl *remoteLayer) Size() (int64, error) {
// Look up the size of this digest in the manifest to avoid a request.
return partial.BlobSize(rl, rl.digest)
}
// ConfigFile implements partial.WithManifestAndConfigFile so that we can use partial.BlobToDiffID below.
func (rl *remoteLayer) ConfigFile() (*v1.ConfigFile, error) {
return partial.ConfigFile(rl.ri)
}
// DiffID implements partial.WithDiffID so that we don't recompute a DiffID that we already have
// available in our ConfigFile.
func (rl *remoteLayer) DiffID() (v1.Hash, error) {
return partial.BlobToDiffID(rl, rl.digest)
}
// LayerByDigest implements partial.CompressedLayer
func (r *remoteImage) LayerByDigest(h v1.Hash) (partial.CompressedLayer, error) {
return &remoteLayer{
ri: r,
digest: h,
}, nil
}