Merge pull request #121 from stevvooe/address-layer-upload-errors

Address server errors received during layer upload

api/v2/descriptors.go

@@ -1263,7 +1263,6 @@ var routeDescriptors = []RouteDescriptor{
 								Description: "An error was encountered processing the delete. The client may ignore this error.",
 								StatusCode:  http.StatusBadRequest,
 								ErrorCodes: []ErrorCode{
-									ErrorCodeDigestInvalid,
 									ErrorCodeNameInvalid,
 									ErrorCodeBlobUploadInvalid,
 								},
@@ -1333,9 +1332,9 @@ var errorDescriptors = []ErrorDescriptor{
 	{
 		Code:    ErrorCodeNameInvalid,
 		Value:   "NAME_INVALID",
-		Message: "manifest name did not match URI",
+		Message: "invalid repository name",
-		Description: `During a manifest upload, if the name in the manifest
+		Description: `Invalid repository name encountered either during
-		does not match the uri name, this error will be returned.`,
+		manifest validation or any API operation.`,
 		HTTPStatusCodes: []int{http.StatusBadRequest, http.StatusNotFound},
 	},
 	{

digest/digest.go

@@ -13,6 +13,11 @@ import (
 	"github.com/docker/docker/pkg/tarsum"
 )
 
+const (
+	// DigestTarSumV1EmptyTar is the digest for the empty tar file.
+	DigestTarSumV1EmptyTar = "tarsum.v1+sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+)
+
 // Digest allows simple protection of hex formatted digest strings, prefixed
 // by their algorithm. Strings of type Digest have some guarantee of being in
 // the correct format and it provides quick access to the components of a

digest/digest_test.go

@@ -1,6 +1,10 @@
 package digest
 
-import "testing"
+import (
+	"bytes"
+	"io"
+	"testing"
+)
 
 func TestParseDigest(t *testing.T) {
 	for _, testcase := range []struct {
@@ -78,3 +82,25 @@ func TestParseDigest(t *testing.T) {
 		}
 	}
 }
+
+// A few test cases used to fix behavior we expect in storage backend.
+
+func TestFromTarArchiveZeroLength(t *testing.T) {
+	checkTarsumDigest(t, "zero-length archive", bytes.NewReader([]byte{}), DigestTarSumV1EmptyTar)
+}
+
+func TestFromTarArchiveEmptyTar(t *testing.T) {
+	// String of 1024 zeros is a valid, empty tar file.
+	checkTarsumDigest(t, "1024 zero bytes", bytes.NewReader(bytes.Repeat([]byte("\x00"), 1024)), DigestTarSumV1EmptyTar)
+}
+
+func checkTarsumDigest(t *testing.T, msg string, rd io.Reader, expected Digest) {
+	dgst, err := FromTarArchive(rd)
+	if err != nil {
+		t.Fatalf("unexpected error digesting %s: %v", msg, err)
+	}
+
+	if dgst != expected {
+		t.Fatalf("unexpected digest for %s: %q != %q", msg, dgst, expected)
+	}
+}

doc/SPEC.md

@@ -2539,7 +2539,6 @@ The error codes that may be included in the response body are enumerated below:
 
 |Code|Message|Description|
 -------|----|------|------------
-| `DIGEST_INVALID` | provided digest did not match uploaded content | When a blob is uploaded, the registry will check that the content matches the digest provided by the client. The error may include a detail structure with the key "digest", including the invalid digest string. This error may also be returned when a manifest includes an invalid layer digest. |
 | `NAME_INVALID` | manifest name did not match URI | During a manifest upload, if the name in the manifest does not match the uri name, this error will be returned. |
 | `BLOB_UPLOAD_INVALID` | blob upload invalid | The blob upload encountered an error and can no longer proceed. |
 

registry/api_test.go

@@ -11,6 +11,7 @@ import (
 	"net/http/httputil"
 	"net/url"
 	"os"
+	"reflect"
 	"testing"
 
 	"github.com/docker/distribution/api/v2"
@@ -120,29 +121,68 @@ func TestLayerAPI(t *testing.T) {
 	checkResponse(t, "checking head on non-existent layer", resp, http.StatusNotFound)
 
 	// ------------------------------------------
-	// Upload a layer
+	// Start an upload and cancel
-	layerUploadURL, err := builder.BuildBlobUploadURL(imageName)
+	uploadURLBase := startPushLayer(t, builder, imageName)
+
+	req, err := http.NewRequest("DELETE", uploadURLBase, nil)
 	if err != nil {
-		t.Fatalf("error building upload url: %v", err)
+		t.Fatalf("unexpected error creating delete request: %v", err)
 	}
 
-	resp, err = http.Post(layerUploadURL, "", nil)
+	resp, err = http.DefaultClient.Do(req)
 	if err != nil {
-		t.Fatalf("error starting layer upload: %v", err)
+		t.Fatalf("unexpected error sending delete request: %v", err)
 	}
 
-	checkResponse(t, "starting layer upload", resp, http.StatusAccepted)
+	checkResponse(t, "deleting upload", resp, http.StatusNoContent)
-	checkHeaders(t, resp, http.Header{
-		"Location":       []string{"*"},
-		"Content-Length": []string{"0"},
-	})
 
+	// A status check should result in 404
+	resp, err = http.Get(uploadURLBase)
+	if err != nil {
+		t.Fatalf("unexpected error getting upload status: %v", err)
+	}
+	checkResponse(t, "status of deleted upload", resp, http.StatusNotFound)
+
+	// -----------------------------------------
+	// Do layer push with an empty body and different digest
+	uploadURLBase = startPushLayer(t, builder, imageName)
+	resp, err = doPushLayer(t, builder, imageName, layerDigest, uploadURLBase, bytes.NewReader([]byte{}))
+	if err != nil {
+		t.Fatalf("unexpected error doing bad layer push: %v", err)
+	}
+
+	checkResponse(t, "bad layer push", resp, http.StatusBadRequest)
+	checkBodyHasErrorCodes(t, "bad layer push", resp, v2.ErrorCodeDigestInvalid)
+
+	// -----------------------------------------
+	// Do layer push with an empty body and correct digest
+	zeroDigest, err := digest.FromTarArchive(bytes.NewReader([]byte{}))
+	if err != nil {
+		t.Fatalf("unexpected error digesting empty buffer: %v", err)
+	}
+
+	uploadURLBase = startPushLayer(t, builder, imageName)
+	pushLayer(t, builder, imageName, zeroDigest, uploadURLBase, bytes.NewReader([]byte{}))
+
+	// -----------------------------------------
+	// Do layer push with an empty body and correct digest
+
+	// This is a valid but empty tarfile!
+	emptyTar := bytes.Repeat([]byte("\x00"), 1024)
+	emptyDigest, err := digest.FromTarArchive(bytes.NewReader(emptyTar))
+	if err != nil {
+		t.Fatalf("unexpected error digesting empty tar: %v", err)
+	}
+
+	uploadURLBase = startPushLayer(t, builder, imageName)
+	pushLayer(t, builder, imageName, emptyDigest, uploadURLBase, bytes.NewReader(emptyTar))
+
+	// ------------------------------------------
+	// Now, actually do successful upload.
 	layerLength, _ := layerFile.Seek(0, os.SEEK_END)
 	layerFile.Seek(0, os.SEEK_SET)
 
-	// TODO(sday): Cancel the layer upload here and restart.
+	uploadURLBase = startPushLayer(t, builder, imageName)
-
-	uploadURLBase := startPushLayer(t, builder, imageName)
 	pushLayer(t, builder, imageName, layerDigest, uploadURLBase, layerFile)
 
 	// ------------------------
@@ -218,27 +258,7 @@ func TestManifestAPI(t *testing.T) {
 	defer resp.Body.Close()
 
 	checkResponse(t, "getting non-existent manifest", resp, http.StatusNotFound)
-
+	checkBodyHasErrorCodes(t, "getting non-existent manifest", resp, v2.ErrorCodeManifestUnknown)
-	// TODO(stevvooe): Shoot. The error setup is not working out. The content-
-	// type headers are being set after writing the status code.
-	// if resp.Header.Get("Content-Type") != "application/json; charset=utf-8" {
-	// 	t.Fatalf("unexpected content type: %v != 'application/json'",
-	// 		resp.Header.Get("Content-Type"))
-	// }
-	dec := json.NewDecoder(resp.Body)
-
-	var respErrs v2.Errors
-	if err := dec.Decode(&respErrs); err != nil {
-		t.Fatalf("unexpected error decoding error response: %v", err)
-	}
-
-	if len(respErrs.Errors) == 0 {
-		t.Fatalf("expected errors in response")
-	}
-
-	if respErrs.Errors[0].Code != v2.ErrorCodeManifestUnknown {
-		t.Fatalf("expected manifest unknown error: got %v", respErrs)
-	}
 
 	tagsURL, err := builder.BuildTagsURL(imageName)
 	if err != nil {
@@ -253,18 +273,7 @@ func TestManifestAPI(t *testing.T) {
 
 	// Check that we get an unknown repository error when asking for tags
 	checkResponse(t, "getting unknown manifest tags", resp, http.StatusNotFound)
-	dec = json.NewDecoder(resp.Body)
+	checkBodyHasErrorCodes(t, "getting unknown manifest tags", resp, v2.ErrorCodeNameUnknown)
-	if err := dec.Decode(&respErrs); err != nil {
-		t.Fatalf("unexpected error decoding error response: %v", err)
-	}
-
-	if len(respErrs.Errors) == 0 {
-		t.Fatalf("expected errors in response")
-	}
-
-	if respErrs.Errors[0].Code != v2.ErrorCodeNameUnknown {
-		t.Fatalf("expected respository unknown error: got %v", respErrs)
-	}
 
 	// --------------------------------
 	// Attempt to push unsigned manifest with missing layers
@@ -284,41 +293,17 @@ func TestManifestAPI(t *testing.T) {
 	resp = putManifest(t, "putting unsigned manifest", manifestURL, unsignedManifest)
 	defer resp.Body.Close()
 	checkResponse(t, "posting unsigned manifest", resp, http.StatusBadRequest)
+	_, p, counts := checkBodyHasErrorCodes(t, "getting unknown manifest tags", resp,
+		v2.ErrorCodeManifestUnverified, v2.ErrorCodeBlobUnknown, v2.ErrorCodeDigestInvalid)
 
-	dec = json.NewDecoder(resp.Body)
+	expectedCounts := map[v2.ErrorCode]int{
-	if err := dec.Decode(&respErrs); err != nil {
+		v2.ErrorCodeManifestUnverified: 1,
-		t.Fatalf("unexpected error decoding error response: %v", err)
+		v2.ErrorCodeBlobUnknown:        2,
+		v2.ErrorCodeDigestInvalid:      2,
 	}
 
-	var unverified int
+	if !reflect.DeepEqual(counts, expectedCounts) {
-	var missingLayers int
+		t.Fatalf("unexpected number of error codes encountered: %v\n!=\n%v\n---\n%s", counts, expectedCounts, string(p))
-	var invalidDigests int
-
-	for _, err := range respErrs.Errors {
-		switch err.Code {
-		case v2.ErrorCodeManifestUnverified:
-			unverified++
-		case v2.ErrorCodeBlobUnknown:
-			missingLayers++
-		case v2.ErrorCodeDigestInvalid:
-			// TODO(stevvooe): This error isn't quite descriptive enough --
-			// the layer with an invalid digest isn't identified.
-			invalidDigests++
-		default:
-			t.Fatalf("unexpected error: %v", err)
-		}
-	}
-
-	if unverified != 1 {
-		t.Fatalf("should have received one unverified manifest error: %v", respErrs)
-	}
-
-	if missingLayers != 2 {
-		t.Fatalf("should have received two missing layer errors: %v", respErrs)
-	}
-
-	if invalidDigests != 2 {
-		t.Fatalf("should have received two invalid digest errors: %v", respErrs)
 	}
 
 	// TODO(stevvooe): Add a test case where we take a mostly valid registry,
@@ -363,7 +348,7 @@ func TestManifestAPI(t *testing.T) {
 	checkResponse(t, "fetching uploaded manifest", resp, http.StatusOK)
 
 	var fetchedManifest manifest.SignedManifest
-	dec = json.NewDecoder(resp.Body)
+	dec := json.NewDecoder(resp.Body)
 	if err := dec.Decode(&fetchedManifest); err != nil {
 		t.Fatalf("error decoding fetched manifest: %v", err)
 	}
@@ -448,11 +433,9 @@ func startPushLayer(t *testing.T, ub *v2.URLBuilder, name string) string {
 	return resp.Header.Get("Location")
 }
 
-// pushLayer pushes the layer content returning the url on success.
+// doPushLayer pushes the layer content returning the url on success returning
-func pushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Digest, uploadURLBase string, rs io.ReadSeeker) string {
+// the response. If you're only expecting a successful response, use pushLayer.
-	rsLength, _ := rs.Seek(0, os.SEEK_END)
+func doPushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Digest, uploadURLBase string, body io.Reader) (*http.Response, error) {
-	rs.Seek(0, os.SEEK_SET)
-
 	u, err := url.Parse(uploadURLBase)
 	if err != nil {
 		t.Fatalf("unexpected error parsing pushLayer url: %v", err)
@@ -462,23 +445,24 @@ func pushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Digest,
 		"_state": u.Query()["_state"],
 
 		"digest": []string{dgst.String()},
-
-		// TODO(stevvooe): Layer upload can be completed with and without size
-		// argument. We'll need to add a test that checks the latter path.
-		"size": []string{fmt.Sprint(rsLength)},
 	}.Encode()
 
 	uploadURL := u.String()
 
 	// Just do a monolithic upload
-	req, err := http.NewRequest("PUT", uploadURL, rs)
+	req, err := http.NewRequest("PUT", uploadURL, body)
 	if err != nil {
 		t.Fatalf("unexpected error creating new request: %v", err)
 	}
 
-	resp, err := http.DefaultClient.Do(req)
+	return http.DefaultClient.Do(req)
+}
+
+// pushLayer pushes the layer content returning the url on success.
+func pushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Digest, uploadURLBase string, body io.Reader) string {
+	resp, err := doPushLayer(t, ub, name, dgst, uploadURLBase, body)
 	if err != nil {
-		t.Fatalf("unexpected error doing put: %v", err)
+		t.Fatalf("unexpected error doing push layer request: %v", err)
 	}
 	defer resp.Body.Close()
 
@@ -506,6 +490,57 @@ func checkResponse(t *testing.T, msg string, resp *http.Response, expectedStatus
 	}
 }
 
+// checkBodyHasErrorCodes ensures the body is an error body and has the
+// expected error codes, returning the error structure, the json slice and a
+// count of the errors by code.
+func checkBodyHasErrorCodes(t *testing.T, msg string, resp *http.Response, errorCodes ...v2.ErrorCode) (v2.Errors, []byte, map[v2.ErrorCode]int) {
+	p, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatalf("unexpected error reading body %s: %v", msg, err)
+	}
+
+	var errs v2.Errors
+	if err := json.Unmarshal(p, &errs); err != nil {
+		t.Fatalf("unexpected error decoding error response: %v", err)
+	}
+
+	if len(errs.Errors) == 0 {
+		t.Fatalf("expected errors in response")
+	}
+
+	// TODO(stevvooe): Shoot. The error setup is not working out. The content-
+	// type headers are being set after writing the status code.
+	// if resp.Header.Get("Content-Type") != "application/json; charset=utf-8" {
+	// 	t.Fatalf("unexpected content type: %v != 'application/json'",
+	// 		resp.Header.Get("Content-Type"))
+	// }
+
+	expected := map[v2.ErrorCode]struct{}{}
+	counts := map[v2.ErrorCode]int{}
+
+	// Initialize map with zeros for expected
+	for _, code := range errorCodes {
+		expected[code] = struct{}{}
+		counts[code] = 0
+	}
+
+	for _, err := range errs.Errors {
+		if _, ok := expected[err.Code]; !ok {
+			t.Fatalf("unexpected error code %v encountered during %s: %s ", err.Code, msg, string(p))
+		}
+		counts[err.Code]++
+	}
+
+	// Ensure that counts of expected errors were all non-zero
+	for code := range expected {
+		if counts[code] == 0 {
+			t.Fatalf("expected error code %v not encounterd during %s: %s", code, msg, string(p))
+		}
+	}
+
+	return errs, p, counts
+}
+
 func maybeDumpResponse(t *testing.T, resp *http.Response) {
 	if d, err := httputil.DumpResponse(resp, true); err != nil {
 		t.Logf("error dumping response: %v", err)

registry/layerupload.go

@@ -23,10 +23,12 @@ func layerUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 	}
 
 	handler := http.Handler(handlers.MethodHandler{
-		"POST":   http.HandlerFunc(luh.StartLayerUpload),
+		"POST": http.HandlerFunc(luh.StartLayerUpload),
-		"GET":    http.HandlerFunc(luh.GetUploadStatus),
+		"GET":  http.HandlerFunc(luh.GetUploadStatus),
-		"HEAD":   http.HandlerFunc(luh.GetUploadStatus),
+		"HEAD": http.HandlerFunc(luh.GetUploadStatus),
-		"PUT":    http.HandlerFunc(luh.PutLayerChunk),
+		// TODO(stevvooe): Must implement patch support.
+		// "PATCH":    http.HandlerFunc(luh.PutLayerChunk),
+		"PUT":    http.HandlerFunc(luh.PutLayerUploadComplete),
 		"DELETE": http.HandlerFunc(luh.CancelLayerUpload),
 	})
 
@@ -158,55 +160,73 @@ func (luh *layerUploadHandler) GetUploadStatus(w http.ResponseWriter, r *http.Re
 	w.WriteHeader(http.StatusNoContent)
 }
 
-// PutLayerChunk receives a layer chunk during the layer upload process,
+// PutLayerUploadComplete takes the final request of a layer upload. The final
-// possible completing the upload with a checksum and length.
+// chunk may include all the layer data, the final chunk of layer data or no
-func (luh *layerUploadHandler) PutLayerChunk(w http.ResponseWriter, r *http.Request) {
+// layer data. Any data provided is received and verified. If successful, the
+// layer is linked into the blob store and 201 Created is returned with the
+// canonical url of the layer.
+func (luh *layerUploadHandler) PutLayerUploadComplete(w http.ResponseWriter, r *http.Request) {
 	if luh.Upload == nil {
 		w.WriteHeader(http.StatusNotFound)
 		luh.Errors.Push(v2.ErrorCodeBlobUploadUnknown)
-	}
-
-	var finished bool
-
-	// TODO(stevvooe): This is woefully incomplete. Missing stuff:
-	//
-	// 1. Extract information from range header, if present.
-	// 2. Check offset of current layer.
-	// 3. Emit correct error responses.
-
-	// Read in the chunk
-	io.Copy(luh.Upload, r.Body)
-
-	if err := luh.maybeCompleteUpload(w, r); err != nil {
-		if err != errNotReadyToComplete {
-			switch err := err.(type) {
-			case storage.ErrLayerInvalidSize:
-				w.WriteHeader(http.StatusBadRequest)
-				luh.Errors.Push(v2.ErrorCodeSizeInvalid, err)
-				return
-			case storage.ErrLayerInvalidDigest:
-				w.WriteHeader(http.StatusBadRequest)
-				luh.Errors.Push(v2.ErrorCodeDigestInvalid, err)
-				return
-			default:
-				w.WriteHeader(http.StatusInternalServerError)
-				luh.Errors.Push(v2.ErrorCodeUnknown, err)
-				return
-			}
-		}
-	}
-
-	if err := luh.layerUploadResponse(w, r); err != nil {
-		w.WriteHeader(http.StatusInternalServerError) // Error conditions here?
-		luh.Errors.Push(v2.ErrorCodeUnknown, err)
 		return
 	}
 
-	if finished {
+	dgstStr := r.FormValue("digest") // TODO(stevvooe): Support multiple digest parameters!
-		w.WriteHeader(http.StatusCreated)
+
-	} else {
+	if dgstStr == "" {
-		w.WriteHeader(http.StatusAccepted)
+		// no digest? return error, but allow retry.
+		w.WriteHeader(http.StatusNotFound)
+		luh.Errors.Push(v2.ErrorCodeDigestInvalid, "digest missing")
+		return
 	}
+
+	dgst, err := digest.ParseDigest(dgstStr)
+	if err != nil {
+		// no digest? return error, but allow retry.
+		w.WriteHeader(http.StatusNotFound)
+		luh.Errors.Push(v2.ErrorCodeDigestInvalid, "digest parsing failed")
+		return
+	}
+
+	// TODO(stevvooe): Check the incoming range header here, per the
+	// specification. LayerUpload should be seeked (sought?) to that position.
+
+	// Read in the final chunk, if any.
+	io.Copy(luh.Upload, r.Body)
+
+	layer, err := luh.Upload.Finish(dgst)
+	if err != nil {
+		switch err := err.(type) {
+		case storage.ErrLayerInvalidDigest:
+			w.WriteHeader(http.StatusBadRequest)
+			luh.Errors.Push(v2.ErrorCodeDigestInvalid, err)
+		default:
+			luh.log.Errorf("unknown error completing upload: %#v", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			luh.Errors.Push(v2.ErrorCodeUnknown, err)
+		}
+
+		// Clean up the backend layer data if there was an error.
+		if err := luh.Upload.Cancel(); err != nil {
+			// If the cleanup fails, all we can do is observe and report.
+			luh.log.Errorf("error canceling upload after error: %v", err)
+		}
+
+		return
+	}
+
+	// Build our canonical layer url
+	layerURL, err := luh.urlBuilder.BuildBlobURL(layer.Name(), layer.Digest())
+	if err != nil {
+		luh.Errors.Push(v2.ErrorCodeUnknown, err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Location", layerURL)
+	w.Header().Set("Content-Length", "0")
+	w.WriteHeader(http.StatusCreated)
 }
 
 // CancelLayerUpload cancels an in-progress upload of a layer.
@@ -214,8 +234,16 @@ func (luh *layerUploadHandler) CancelLayerUpload(w http.ResponseWriter, r *http.
 	if luh.Upload == nil {
 		w.WriteHeader(http.StatusNotFound)
 		luh.Errors.Push(v2.ErrorCodeBlobUploadUnknown)
+		return
 	}
 
+	if err := luh.Upload.Cancel(); err != nil {
+		luh.log.Errorf("error encountered canceling upload: %v", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		luh.Errors.PushErr(err)
+	}
+
+	w.WriteHeader(http.StatusNoContent)
 }
 
 // layerUploadResponse provides a standard request for uploading layers and
@@ -257,45 +285,3 @@ func (luh *layerUploadHandler) layerUploadResponse(w http.ResponseWriter, r *htt
 
 	return nil
 }
-
-var errNotReadyToComplete = fmt.Errorf("not ready to complete upload")
-
-// maybeCompleteUpload tries to complete the upload if the correct parameters
-// are available. Returns errNotReadyToComplete if not ready to complete.
-func (luh *layerUploadHandler) maybeCompleteUpload(w http.ResponseWriter, r *http.Request) error {
-	// If we get a digest and length, we can finish the upload.
-	dgstStr := r.FormValue("digest") // TODO(stevvooe): Support multiple digest parameters!
-
-	if dgstStr == "" {
-		return errNotReadyToComplete
-	}
-
-	dgst, err := digest.ParseDigest(dgstStr)
-	if err != nil {
-		return err
-	}
-
-	luh.completeUpload(w, r, dgst)
-	return nil
-}
-
-// completeUpload finishes out the upload with the correct response.
-func (luh *layerUploadHandler) completeUpload(w http.ResponseWriter, r *http.Request, dgst digest.Digest) {
-	layer, err := luh.Upload.Finish(dgst)
-	if err != nil {
-		luh.Errors.Push(v2.ErrorCodeUnknown, err)
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-
-	layerURL, err := luh.urlBuilder.BuildBlobURL(layer.Name(), layer.Digest())
-	if err != nil {
-		luh.Errors.Push(v2.ErrorCodeUnknown, err)
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-
-	w.Header().Set("Location", layerURL)
-	w.Header().Set("Content-Length", "0")
-	w.WriteHeader(http.StatusCreated)
-}

storage/filereader.go

@@ -2,14 +2,23 @@ package storage
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"os"
 	"time"
 
 	"github.com/docker/distribution/storagedriver"
 )
 
+// TODO(stevvooe): Set an optimal buffer size here. We'll have to
+// understand the latency characteristics of the underlying network to
+// set this correctly, so we may want to leave it to the driver. For
+// out of process drivers, we'll have to optimize this buffer size for
+// local communication.
+const fileReaderBufferSize = 4 << 20
+
 // remoteFileReader provides a read seeker interface to files stored in
 // storagedriver. Used to implement part of layer interface and will be used
 // to implement read side of LayerUpload.
@@ -28,24 +37,40 @@ type fileReader struct {
 	err    error         // terminal error, if set, reader is closed
 }
 
+// newFileReader initializes a file reader for the remote file. The read takes
+// on the offset and size at the time the reader is created. If the underlying
+// file changes, one must create a new fileReader.
 func newFileReader(driver storagedriver.StorageDriver, path string) (*fileReader, error) {
+	rd := &fileReader{
+		driver: driver,
+		path:   path,
+	}
+
 	// Grab the size of the layer file, ensuring existence.
-	fi, err := driver.Stat(path)
+	if fi, err := driver.Stat(path); err != nil {
+		switch err := err.(type) {
+		case storagedriver.PathNotFoundError:
+			// NOTE(stevvooe): We really don't care if the file is not
+			// actually present for the reader. If the caller needs to know
+			// whether or not the file exists, they should issue a stat call
+			// on the path. There is still no guarantee, since the file may be
+			// gone by the time the reader is created. The only correct
+			// behavior is to return a reader that immediately returns EOF.
+		default:
+			// Any other error we want propagated up the stack.
+			return nil, err
+		}
+	} else {
+		if fi.IsDir() {
+			return nil, fmt.Errorf("cannot read a directory")
+		}
 
-	if err != nil {
+		// Fill in file information
-		return nil, err
+		rd.size = fi.Size()
+		rd.modtime = fi.ModTime()
 	}
 
-	if fi.IsDir() {
+	return rd, nil
-		return nil, fmt.Errorf("cannot read a directory")
-	}
-
-	return &fileReader{
-		driver:  driver,
-		path:    path,
-		size:    fi.Size(),
-		modtime: fi.ModTime(),
-	}, nil
 }
 
 func (fr *fileReader) Read(p []byte) (n int, err error) {
@@ -88,8 +113,6 @@ func (fr *fileReader) Seek(offset int64, whence int) (int64, error) {
 
 	if newOffset < 0 {
 		err = fmt.Errorf("cannot seek to negative position")
-	} else if newOffset > fr.size {
-		err = fmt.Errorf("cannot seek passed end of file")
 	} else {
 		if fr.offset != newOffset {
 			fr.reset()
@@ -134,9 +157,17 @@ func (fr *fileReader) reader() (io.Reader, error) {
 
 	// If we don't have a reader, open one up.
 	rc, err := fr.driver.ReadStream(fr.path, fr.offset)
-
 	if err != nil {
-		return nil, err
+		switch err := err.(type) {
+		case storagedriver.PathNotFoundError:
+			// NOTE(stevvooe): If the path is not found, we simply return a
+			// reader that returns io.EOF. However, we do not set fr.rc,
+			// allowing future attempts at getting a reader to possibly
+			// succeed if the file turns up later.
+			return ioutil.NopCloser(bytes.NewReader([]byte{})), nil
+		default:
+			return nil, err
+		}
 	}
 
 	fr.rc = rc
@@ -147,7 +178,7 @@ func (fr *fileReader) reader() (io.Reader, error) {
 		// set this correctly, so we may want to leave it to the driver. For
 		// out of process drivers, we'll have to optimize this buffer size for
 		// local communication.
-		fr.brd = bufio.NewReader(fr.rc)
+		fr.brd = bufio.NewReaderSize(fr.rc, fileReaderBufferSize)
 	} else {
 		fr.brd.Reset(fr.rc)
 	}

storage/filereader_test.go

@@ -124,7 +124,7 @@ func TestFileReaderSeek(t *testing.T) {
 		t.Fatalf("expected to seek to end: %v != %v", end, len(content))
 	}
 
-	// 4. Seek past end and before start, ensure error.
+	// 4. Seek before start, ensure error.
 
 	// seek before start
 	before, err := fr.Seek(-1, os.SEEK_SET)
@@ -132,9 +132,44 @@ func TestFileReaderSeek(t *testing.T) {
 		t.Fatalf("error expected, returned offset=%v", before)
 	}
 
-	after, err := fr.Seek(int64(len(content)+1), os.SEEK_END)
+	// 5. Seek after end,
-	if err == nil {
+	after, err := fr.Seek(1, os.SEEK_END)
-		t.Fatalf("error expected, returned offset=%v", after)
+	if err != nil {
+		t.Fatalf("unexpected error expected, returned offset=%v", after)
+	}
+
+	p := make([]byte, 16)
+	n, err := fr.Read(p)
+
+	if n != 0 {
+		t.Fatalf("bytes reads %d != %d", n, 0)
+	}
+
+	if err != io.EOF {
+		t.Fatalf("expected io.EOF, got %v", err)
+	}
+}
+
+// TestFileReaderNonExistentFile ensures the reader behaves as expected with a
+// missing or zero-length remote file. While the file may not exist, the
+// reader should not error out on creation and should return 0-bytes from the
+// read method, with an io.EOF error.
+func TestFileReaderNonExistentFile(t *testing.T) {
+	driver := inmemory.New()
+	fr, err := newFileReader(driver, "/doesnotexist")
+	if err != nil {
+		t.Fatalf("unexpected error initializing reader: %v", err)
+	}
+
+	var buf [1024]byte
+
+	n, err := fr.Read(buf[:])
+	if n != 0 {
+		t.Fatalf("non-zero byte read reported: %d != 0", n)
+	}
+
+	if err != io.EOF {
+		t.Fatalf("read on missing file should return io.EOF, got %v", err)
 	}
 }
 

storage/filewriter.go

@@ -99,9 +99,6 @@ func (fw *fileWriter) Seek(offset int64, whence int) (int64, error) {
 
 	if newOffset < 0 {
 		err = fmt.Errorf("cannot seek to negative position")
-	} else if newOffset > fw.size {
-		fw.offset = newOffset
-		fw.size = newOffset
 	} else {
 		// No problems, set the offset.
 		fw.offset = newOffset

storage/layer.go

@@ -80,17 +80,10 @@ func (err ErrUnknownLayer) Error() string {
 // ErrLayerInvalidDigest returned when tarsum check fails.
 type ErrLayerInvalidDigest struct {
 	Digest digest.Digest
+	Reason error
 }
 
 func (err ErrLayerInvalidDigest) Error() string {
-	return fmt.Sprintf("invalid digest for referenced layer: %v", err.Digest)
+	return fmt.Sprintf("invalid digest for referenced layer: %v, %v",
-}
+		err.Digest, err.Reason)
-
-// ErrLayerInvalidSize returned when length check fails.
-type ErrLayerInvalidSize struct {
-	Size int64
-}
-
-func (err ErrLayerInvalidSize) Error() string {
-	return fmt.Sprintf("invalid layer size: %d", err.Size)
 }

storage/layer_test.go

@@ -235,6 +235,40 @@ func TestSimpleLayerRead(t *testing.T) {
 	}
 }
 
+// TestLayerUploadZeroLength uploads zero-length
+func TestLayerUploadZeroLength(t *testing.T) {
+	imageName := "foo/bar"
+	driver := inmemory.New()
+	registry := NewRegistryWithDriver(driver)
+	ls := registry.Repository(imageName).Layers()
+
+	upload, err := ls.Upload()
+	if err != nil {
+		t.Fatalf("unexpected error starting upload: %v", err)
+	}
+
+	io.Copy(upload, bytes.NewReader([]byte{}))
+
+	dgst, err := digest.FromTarArchive(bytes.NewReader([]byte{}))
+	if err != nil {
+		t.Fatalf("error getting zero digest: %v", err)
+	}
+
+	if dgst != digest.DigestTarSumV1EmptyTar {
+		// sanity check on zero digest
+		t.Fatalf("digest not as expected: %v != %v", dgst, digest.DigestTarSumV1EmptyTar)
+	}
+
+	layer, err := upload.Finish(dgst)
+	if err != nil {
+		t.Fatalf("unexpected error finishing upload: %v", err)
+	}
+
+	if layer.Digest() != dgst {
+		t.Fatalf("unexpected digest: %v != %v", layer.Digest(), dgst)
+	}
+}
+
 // writeRandomLayer creates a random layer under name and tarSum using driver
 // and pathMapper. An io.ReadSeeker with the data is returned, along with the
 // sha256 hex digest.

storage/layerupload.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"fmt"
 	"io"
 	"path"
 	"time"
@@ -89,7 +90,10 @@ func (luc *layerUploadController) validateLayer(dgst digest.Digest) (digest.Dige
 	case tarsum.Version1:
 	default:
 		// version 0 and dev, for now.
-		return "", ErrLayerTarSumVersionUnsupported
+		return "", ErrLayerInvalidDigest{
+			Digest: dgst,
+			Reason: ErrLayerTarSumVersionUnsupported,
+		}
 	}
 
 	digestVerifier := digest.NewDigestVerifier(dgst)
@@ -117,7 +121,10 @@ func (luc *layerUploadController) validateLayer(dgst digest.Digest) (digest.Dige
 	}
 
 	if !digestVerifier.Verified() {
-		return "", ErrLayerInvalidDigest{Digest: dgst}
+		return "", ErrLayerInvalidDigest{
+			Digest: dgst,
+			Reason: fmt.Errorf("content does not match digest"),
+		}
 	}
 
 	return canonical, nil
@@ -136,7 +143,7 @@ func (luc *layerUploadController) moveLayer(dgst digest.Digest) error {
 	}
 
 	// Check for existence
-	if _, err := luc.layerStore.repository.registry.driver.Stat(blobPath); err != nil {
+	if _, err := luc.driver.Stat(blobPath); err != nil {
 		switch err := err.(type) {
 		case storagedriver.PathNotFoundError:
 			break // ensure that it doesn't exist.
@@ -151,6 +158,31 @@ func (luc *layerUploadController) moveLayer(dgst digest.Digest) error {
 		return nil
 	}
 
+	// If no data was received, we may not actually have a file on disk. Check
+	// the size here and write a zero-length file to blobPath if this is the
+	// case. For the most part, this should only ever happen with zero-length
+	// tars.
+	if _, err := luc.driver.Stat(luc.path); err != nil {
+		switch err := err.(type) {
+		case storagedriver.PathNotFoundError:
+			// HACK(stevvooe): This is slightly dangerous: if we verify above,
+			// get a hash, then the underlying file is deleted, we risk moving
+			// a zero-length blob into a nonzero-length blob location. To
+			// prevent this horrid thing, we employ the hack of only allowing
+			// to this happen for the zero tarsum.
+			if dgst == digest.DigestTarSumV1EmptyTar {
+				return luc.driver.PutContent(blobPath, []byte{})
+			}
+
+			// We let this fail during the move below.
+			logrus.
+				WithField("upload.uuid", luc.UUID()).
+				WithField("digest", dgst).Warnf("attempted to move zero-length content with non-zero digest")
+		default:
+			return err // unrelated error
+		}
+	}
+
 	return luc.driver.Move(luc.path, blobPath)
 }
 

storage/revisionstore.go

@@ -57,8 +57,6 @@ func (rs *revisionStore) get(revision digest.Digest) (*manifest.SignedManifest,
 		return nil, err
 	}
 
-	logrus.Infof("retrieved signatures: %v", string(signatures[0]))
-
 	jsig, err := libtrust.NewJSONSignature(content, signatures...)
 	if err != nil {
 		return nil, err