distribution/registry/handlers/images.go
Stephen J Day c9aaff00f8
manifest: references should cover all children
To allow generic manifest walking, we define an interface method of
`References` that returns the referenced items in the manifest. The
current implementation does not return the config target from schema2,
making this useless for most applications.

The garbage collector has been modified to show the utility of this
correctly formed `References` method. We may be able to make more
generic traversal methods with this, as well.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2016-10-18 11:43:33 -07:00

386 lines
12 KiB
Go

package handlers
import (
"bytes"
"fmt"
"net/http"
"strings"
"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/reference"
"github.com/docker/distribution/registry/api/errcode"
"github.com/docker/distribution/registry/api/v2"
"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 {
imageManifestHandler := &imageManifestHandler{
Context: ctx,
}
reference := getReference(ctx)
dgst, err := digest.ParseDigest(reference)
if err != nil {
// We just have a tag
imageManifestHandler.Tag = reference
} else {
imageManifestHandler.Digest = dgst
}
mhandler := handlers.MethodHandler{
"GET": http.HandlerFunc(imageManifestHandler.GetImageManifest),
"HEAD": http.HandlerFunc(imageManifestHandler.GetImageManifest),
}
if !ctx.readOnly {
mhandler["PUT"] = http.HandlerFunc(imageManifestHandler.PutImageManifest)
mhandler["DELETE"] = http.HandlerFunc(imageManifestHandler.DeleteImageManifest)
}
return mhandler
}
// imageManifestHandler handles http operations on image manifests.
type imageManifestHandler struct {
*Context
// One of tag or digest gets set, depending on what is present in context.
Tag string
Digest digest.Digest
}
// GetImageManifest fetches the image manifest from the storage backend, if it exists.
func (imh *imageManifestHandler) GetImageManifest(w http.ResponseWriter, r *http.Request) {
ctxu.GetLogger(imh).Debug("GetImageManifest")
manifests, err := imh.Repository.Manifests(imh)
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
var manifest distribution.Manifest
if imh.Tag != "" {
tags := imh.Repository.Tags(imh)
desc, err := tags.Get(imh, imh.Tag)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown.WithDetail(err))
return
}
imh.Digest = desc.Digest
}
if etagMatch(r, imh.Digest.String()) {
w.WriteHeader(http.StatusNotModified)
return
}
var options []distribution.ManifestServiceOption
if imh.Tag != "" {
options = append(options, distribution.WithTag(imh.Tag))
}
manifest, err = manifests.Get(imh, imh.Digest, options...)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown.WithDetail(err))
return
}
supportsSchema2 := false
supportsManifestList := false
// this parsing of Accept headers is not quite as full-featured as godoc.org's parser, but we don't care about "q=" values
// https://github.com/golang/gddo/blob/e91d4165076d7474d20abda83f92d15c7ebc3e81/httputil/header/header.go#L165-L202
for _, acceptHeader := range r.Header["Accept"] {
// r.Header[...] is a slice in case the request contains the same header more than once
// if the header isn't set, we'll get the zero value, which "range" will handle gracefully
// we need to split each header value on "," to get the full list of "Accept" values (per RFC 2616)
// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
for _, mediaType := range strings.Split(acceptHeader, ",") {
// remove "; q=..." if present
if i := strings.Index(mediaType, ";"); i >= 0 {
mediaType = mediaType[:i]
}
// it's common (but not required) for Accept values to be space separated ("a/b, c/d, e/f")
mediaType = strings.TrimSpace(mediaType)
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 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 manifestDigest == "" {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown)
return
}
manifest, err = manifests.Get(imh, manifestDigest)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown.WithDetail(err))
return
}
// If necessary, convert the image manifest
if schema2Manifest, isSchema2 := manifest.(*schema2.DeserializedManifest); isSchema2 && !supportsSchema2 {
manifest, err = imh.convertSchema2Manifest(schema2Manifest)
if err != nil {
return
}
}
}
ct, p, err := manifest.Payload()
if err != nil {
return
}
w.Header().Set("Content-Type", ct)
w.Header().Set("Content-Length", fmt.Sprint(len(p)))
w.Header().Set("Docker-Content-Digest", imh.Digest.String())
w.Header().Set("Etag", fmt.Sprintf(`"%s"`, imh.Digest))
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
}
ref := imh.Repository.Named()
if imh.Tag != "" {
ref, err = reference.WithTag(ref, imh.Tag)
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeTagInvalid.WithDetail(err))
return nil, err
}
}
builder := schema1.NewConfigManifestBuilder(imh.Repository.Blobs(imh), imh.Context.App.trustKey, ref, configJSON)
for _, d := range schema2Manifest.Layers {
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
}
imh.Digest = digest.FromBytes(manifest.(*schema1.SignedManifest).Canonical)
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
return true
}
}
return false
}
// PutImageManifest validates and stores an image in the registry.
func (imh *imageManifestHandler) PutImageManifest(w http.ResponseWriter, r *http.Request) {
ctxu.GetLogger(imh).Debug("PutImageManifest")
manifests, err := imh.Repository.Manifests(imh)
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
var jsonBuf bytes.Buffer
if err := copyFullPayload(w, r, &jsonBuf, imh, "image manifest PUT", &imh.Errors); err != nil {
// copyFullPayload reports the error if necessary
return
}
mediaType := r.Header.Get("Content-Type")
manifest, desc, err := distribution.UnmarshalManifest(mediaType, jsonBuf.Bytes())
if err != nil {
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
return
}
if imh.Digest != "" {
if desc.Digest != imh.Digest {
ctxu.GetLogger(imh).Errorf("payload digest does match: %q != %q", desc.Digest, imh.Digest)
imh.Errors = append(imh.Errors, v2.ErrorCodeDigestInvalid)
return
}
} else if imh.Tag != "" {
imh.Digest = desc.Digest
} else {
imh.Errors = append(imh.Errors, v2.ErrorCodeTagInvalid.WithDetail("no tag or digest specified"))
return
}
var options []distribution.ManifestServiceOption
if imh.Tag != "" {
options = append(options, distribution.WithTag(imh.Tag))
}
_, err = manifests.Put(imh, manifest, options...)
if err != nil {
// TODO(stevvooe): These error handling switches really need to be
// handled by an app global mapper.
if err == distribution.ErrUnsupported {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnsupported)
return
}
if err == distribution.ErrAccessDenied {
imh.Errors = append(imh.Errors, errcode.ErrorCodeDenied)
return
}
switch err := err.(type) {
case distribution.ErrManifestVerification:
for _, verificationError := range err {
switch verificationError := verificationError.(type) {
case distribution.ErrManifestBlobUnknown:
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestBlobUnknown.WithDetail(verificationError.Digest))
case distribution.ErrManifestNameInvalid:
imh.Errors = append(imh.Errors, v2.ErrorCodeNameInvalid.WithDetail(err))
case distribution.ErrManifestUnverified:
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnverified)
default:
if verificationError == digest.ErrDigestInvalidFormat {
imh.Errors = append(imh.Errors, v2.ErrorCodeDigestInvalid)
} else {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown, verificationError)
}
}
}
case errcode.Error:
imh.Errors = append(imh.Errors, err)
default:
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
}
return
}
// Tag this manifest
if imh.Tag != "" {
tags := imh.Repository.Tags(imh)
err = tags.Tag(imh, imh.Tag, desc)
if err != nil {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
return
}
}
// Construct a canonical url for the uploaded manifest.
ref, err := reference.WithDigest(imh.Repository.Named(), imh.Digest)
if err != nil {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
return
}
location, err := imh.urlBuilder.BuildManifestURL(ref)
if err != nil {
// NOTE(stevvooe): Given the behavior above, this absurdly unlikely to
// happen. We'll log the error here but proceed as if it worked. Worst
// case, we set an empty location header.
ctxu.GetLogger(imh).Errorf("error building manifest url from digest: %v", err)
}
w.Header().Set("Location", location)
w.Header().Set("Docker-Content-Digest", imh.Digest.String())
w.WriteHeader(http.StatusCreated)
}
// DeleteImageManifest removes the manifest with the given digest from the registry.
func (imh *imageManifestHandler) DeleteImageManifest(w http.ResponseWriter, r *http.Request) {
ctxu.GetLogger(imh).Debug("DeleteImageManifest")
manifests, err := imh.Repository.Manifests(imh)
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
err = manifests.Delete(imh, imh.Digest)
if err != nil {
switch err {
case digest.ErrDigestUnsupported:
case digest.ErrDigestInvalidFormat:
imh.Errors = append(imh.Errors, v2.ErrorCodeDigestInvalid)
return
case distribution.ErrBlobUnknown:
imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown)
return
case distribution.ErrUnsupported:
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnsupported)
return
default:
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown)
return
}
}
tagService := imh.Repository.Tags(imh)
referencedTags, err := tagService.Lookup(imh, distribution.Descriptor{Digest: imh.Digest})
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
for _, tag := range referencedTags {
if err := tagService.Untag(imh, tag); err != nil {
imh.Errors = append(imh.Errors, err)
return
}
}
w.WriteHeader(http.StatusAccepted)
}