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Recognize clients that don't support manifest lists

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Convert a default platform's manifest to schema1 on the fly.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This commit is contained in:
Aaron Lehmann
2015-12-17 17:32:11 -08:00
parent 9c416f0e94
commit 697af09566
2 changed files with 129 additions and 27 deletions
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107
registry/handlers/images.go
View File

@@ -8,6 +8,7 @@ import (
"github.com/docker/distribution"
ctxu "github.com/docker/distribution/context"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest/manifestlist"
"github.com/docker/distribution/manifest/schema1"
"github.com/docker/distribution/manifest/schema2"
"github.com/docker/distribution/registry/api/errcode"
@@ -15,6 +16,13 @@ import (
"github.com/gorilla/handlers"
)
// These constants determine which architecture and OS to choose from a
// manifest list when downconverting it to a schema1 manifest.
const (
defaultArch = "amd64"
defaultOS = "linux"
)
// imageManifestDispatcher takes the request context and builds the
// appropriate handler for handling image manifest requests.
func imageManifestDispatcher(ctx *Context, r *http.Request) http.Handler {
@@ -83,42 +91,62 @@ func (imh *imageManifestHandler) GetImageManifest(w http.ResponseWriter, r *http
return
}
supportsSchema2 := false
supportsManifestList := false
if acceptHeaders, ok := r.Header["Accept"]; ok {
for _, mediaType := range acceptHeaders {
if mediaType == schema2.MediaTypeManifest {
supportsSchema2 = true
}
if mediaType == manifestlist.MediaTypeManifestList {
supportsManifestList = true
}
}
}
schema2Manifest, isSchema2 := manifest.(*schema2.DeserializedManifest)
manifestList, isManifestList := manifest.(*manifestlist.DeserializedManifestList)
// Only rewrite schema2 manifests when they are being fetched by tag.
// If they are being fetched by digest, we can't return something not
// matching the digest.
if schema2Manifest, isSchema2 := manifest.(*schema2.DeserializedManifest); imh.Tag != "" && isSchema2 {
supportsSchema2 := false
if acceptHeaders, ok := r.Header["Accept"]; ok {
for _, mediaType := range acceptHeaders {
if mediaType == schema2.MediaTypeManifest {
supportsSchema2 = true
break
}
if imh.Tag != "" && isSchema2 && !supportsSchema2 {
// Rewrite manifest in schema1 format
ctxu.GetLogger(imh).Infof("rewriting manifest %s in schema1 format to support old client", imh.Digest.String())
manifest, err = imh.convertSchema2Manifest(schema2Manifest)
if err != nil {
return
}
} else if imh.Tag != "" && isManifestList && !supportsManifestList {
// Rewrite manifest in schema1 format
ctxu.GetLogger(imh).Infof("rewriting manifest list %s in schema1 format to support old client", imh.Digest.String())
// Find the image manifest corresponding to the default
// platform
var manifestDigest digest.Digest
for _, manifestDescriptor := range manifestList.Manifests {
if manifestDescriptor.Platform.Architecture == defaultArch && manifestDescriptor.Platform.OS == defaultOS {
manifestDigest = manifestDescriptor.Digest
break
}
}
if !supportsSchema2 {
// Rewrite manifest in schema1 format
ctxu.GetLogger(imh).Infof("rewriting manifest %s in schema1 format to support old client", imh.Digest.String())
if manifestDigest == "" {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown)
return
}
targetDescriptor := schema2Manifest.Target()
blobs := imh.Repository.Blobs(imh)
configJSON, err := blobs.Get(imh, targetDescriptor.Digest)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
return
}
manifest, err = manifests.Get(imh, manifestDigest)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown.WithDetail(err))
return
}
builder := schema1.NewConfigManifestBuilder(imh.Repository.Blobs(imh), imh.Context.App.trustKey, imh.Repository.Name(), imh.Tag, configJSON)
for _, d := range manifest.References() {
if err := builder.AppendReference(d); err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
return
}
}
manifest, err = builder.Build(imh)
// If necessary, convert the image manifest
if schema2Manifest, isSchema2 := manifest.(*schema2.DeserializedManifest); isSchema2 && !supportsSchema2 {
manifest, err = imh.convertSchema2Manifest(schema2Manifest)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
return
}
}
@@ -136,6 +164,31 @@ func (imh *imageManifestHandler) GetImageManifest(w http.ResponseWriter, r *http
w.Write(p)
}
func (imh *imageManifestHandler) convertSchema2Manifest(schema2Manifest *schema2.DeserializedManifest) (distribution.Manifest, error) {
targetDescriptor := schema2Manifest.Target()
blobs := imh.Repository.Blobs(imh)
configJSON, err := blobs.Get(imh, targetDescriptor.Digest)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
return nil, err
}
builder := schema1.NewConfigManifestBuilder(imh.Repository.Blobs(imh), imh.Context.App.trustKey, imh.Repository.Name(), imh.Tag, configJSON)
for _, d := range schema2Manifest.References() {
if err := builder.AppendReference(d); err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
return nil, err
}
}
manifest, err := builder.Build(imh)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
return nil, err
}
return manifest, nil
}
func etagMatch(r *http.Request, etag string) bool {
for _, headerVal := range r.Header["If-None-Match"] {
if headerVal == etag || headerVal == fmt.Sprintf(`"%s"`, etag) { // allow quoted or unquoted