Modify blob upload API

- Ensures new uploads and resumed upload statuses always return an offset of 0. This allows future clients which support resumable upload to not attempt resumable upload on this version which does not support it.
- Add PATCH support for streaming data on upload.
- Add messaging to specification that PATCH with content range is currently not supported.
- Update PUT blob to only support full data or no data, no more last chunk messaging as it was not supported.

closes #470

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

docs/handlers/api_test.go

@@ -209,6 +209,13 @@ func TestLayerAPI(t *testing.T) {
 	uploadURLBase, uploadUUID = startPushLayer(t, env.builder, imageName)
 	pushLayer(t, env.builder, imageName, layerDigest, uploadURLBase, layerFile)
 
+	// ------------------------------------------
+	// Now, push just a chunk
+	layerFile.Seek(0, 0)
+
+	uploadURLBase, uploadUUID = startPushLayer(t, env.builder, imageName)
+	uploadURLBase, dgst := pushChunk(t, env.builder, imageName, uploadURLBase, layerFile, layerLength)
+	finishUpload(t, env.builder, imageName, uploadURLBase, dgst)
 	// ------------------------
 	// Use a head request to see if the layer exists.
 	resp, err = http.Head(layerURL)
@@ -616,6 +623,75 @@ func pushLayer(t *testing.T, ub *v2.URLBuilder, name string, dgst digest.Digest,
 	return resp.Header.Get("Location")
 }
 
+func finishUpload(t *testing.T, ub *v2.URLBuilder, name string, uploadURLBase string, dgst digest.Digest) string {
+	resp, err := doPushLayer(t, ub, name, dgst, uploadURLBase, nil)
+	if err != nil {
+		t.Fatalf("unexpected error doing push layer request: %v", err)
+	}
+	defer resp.Body.Close()
+
+	checkResponse(t, "putting monolithic chunk", resp, http.StatusCreated)
+
+	expectedLayerURL, err := ub.BuildBlobURL(name, dgst)
+	if err != nil {
+		t.Fatalf("error building expected layer url: %v", err)
+	}
+
+	checkHeaders(t, resp, http.Header{
+		"Location":              []string{expectedLayerURL},
+		"Content-Length":        []string{"0"},
+		"Docker-Content-Digest": []string{dgst.String()},
+	})
+
+	return resp.Header.Get("Location")
+}
+
+func doPushChunk(t *testing.T, uploadURLBase string, body io.Reader) (*http.Response, digest.Digest, error) {
+	u, err := url.Parse(uploadURLBase)
+	if err != nil {
+		t.Fatalf("unexpected error parsing pushLayer url: %v", err)
+	}
+
+	u.RawQuery = url.Values{
+		"_state": u.Query()["_state"],
+	}.Encode()
+
+	uploadURL := u.String()
+
+	digester := digest.NewCanonicalDigester()
+
+	req, err := http.NewRequest("PATCH", uploadURL, io.TeeReader(body, digester))
+	if err != nil {
+		t.Fatalf("unexpected error creating new request: %v", err)
+	}
+	req.Header.Set("Content-Type", "application/octet-stream")
+
+	resp, err := http.DefaultClient.Do(req)
+
+	return resp, digester.Digest(), err
+}
+
+func pushChunk(t *testing.T, ub *v2.URLBuilder, name string, uploadURLBase string, body io.Reader, length int64) (string, digest.Digest) {
+	resp, dgst, err := doPushChunk(t, uploadURLBase, body)
+	if err != nil {
+		t.Fatalf("unexpected error doing push layer request: %v", err)
+	}
+	defer resp.Body.Close()
+
+	checkResponse(t, "putting chunk", resp, http.StatusAccepted)
+
+	if err != nil {
+		t.Fatalf("error generating sha256 digest of body")
+	}
+
+	checkHeaders(t, resp, http.Header{
+		"Range":          []string{fmt.Sprintf("0-%d", length-1)},
+		"Content-Length": []string{"0"},
+	})
+
+	return resp.Header.Get("Location"), dgst
+}
+
 func checkResponse(t *testing.T, msg string, resp *http.Response, expectedStatus int) {
 	if resp.StatusCode != expectedStatus {
 		t.Logf("unexpected status %s: %v != %v", msg, resp.StatusCode, expectedStatus)