From 697af09566a1957c41f1786efa209e2b0d8963ce Mon Sep 17 00:00:00 2001 From: Aaron Lehmann Date: Thu, 17 Dec 2015 17:32:11 -0800 Subject: [PATCH] Recognize clients that don't support manifest lists Convert a default platform's manifest to schema1 on the fly. Signed-off-by: Aaron Lehmann --- registry/handlers/api_test.go | 49 ++++++++++++++++ registry/handlers/images.go | 107 +++++++++++++++++++++++++--------- 2 files changed, 129 insertions(+), 27 deletions(-) diff --git a/registry/handlers/api_test.go b/registry/handlers/api_test.go index 0393c8f1..50a8cb47 100644 --- a/registry/handlers/api_test.go +++ b/registry/handlers/api_test.go @@ -1567,6 +1567,55 @@ func testManifestAPIManifestList(t *testing.T, env *testEnv, args manifestArgs) } checkResponse(t, "fetching manifest by dgst with etag", resp, http.StatusNotModified) + + // ------------------ + // Fetch as a schema1 manifest + resp, err = http.Get(manifestURL) + if err != nil { + t.Fatalf("unexpected error fetching manifest list as schema1: %v", err) + } + defer resp.Body.Close() + + checkResponse(t, "fetching uploaded manifest list as schema1", resp, http.StatusOK) + checkHeaders(t, resp, http.Header{ + "Docker-Content-Digest": []string{dgst.String()}, + "ETag": []string{fmt.Sprintf(`"%s"`, dgst)}, + }) + + var fetchedSchema1Manifest schema1.SignedManifest + dec = json.NewDecoder(resp.Body) + + if err := dec.Decode(&fetchedSchema1Manifest); err != nil { + t.Fatalf("error decoding fetched schema1 manifest: %v", err) + } + + if fetchedSchema1Manifest.Manifest.SchemaVersion != 1 { + t.Fatal("wrong schema version") + } + if fetchedSchema1Manifest.Architecture != "amd64" { + t.Fatal("wrong architecture") + } + if fetchedSchema1Manifest.Name != imageName { + t.Fatal("wrong image name") + } + if fetchedSchema1Manifest.Tag != tag { + t.Fatal("wrong tag") + } + if len(fetchedSchema1Manifest.FSLayers) != 2 { + t.Fatal("wrong number of FSLayers") + } + layers := args.manifest.(*schema2.DeserializedManifest).Layers + for i := range layers { + if fetchedSchema1Manifest.FSLayers[i].BlobSum != layers[len(layers)-i-1].Digest { + t.Fatalf("blob digest mismatch in schema1 manifest for layer %d", i) + } + } + if len(fetchedSchema1Manifest.History) != 2 { + t.Fatal("wrong number of History entries") + } + + // Don't check V1Compatibility fields becuase we're using randomly-generated + // layers. } func testManifestDelete(t *testing.T, env *testEnv, args manifestArgs) { diff --git a/registry/handlers/images.go b/registry/handlers/images.go index 6c8a16fb..240bbffe 100644 --- a/registry/handlers/images.go +++ b/registry/handlers/images.go @@ -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