Merge branch 'format-patch' into 'master'

Workhorse to serve the output for format-patch

Now this is done by Rails which is sad for the Unicorn worker, so this
is moved here. This commit excludes tests for now, which will be added
after the weekend.

Part of fixing: gitlab-org/gitlab-ce#13999

See merge request !48

internal/git/format-patch.go

+package git
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/helper"
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/senddata"
+)
+
+type patch struct{ senddata.Prefix }
+type patchParams struct {
+	RepoPath string
+	ShaFrom  string
+	ShaTo    string
+}
+
+var SendPatch = &patch{"git-format-patch:"}
+
+func (p *patch) Inject(w http.ResponseWriter, r *http.Request, sendData string) {
+	var params patchParams
+	if err := p.Unpack(&params, sendData); err != nil {
+		helper.Fail500(w, fmt.Errorf("SendPatch: unpack sendData: %v", err))
+		return
+	}
+
+	log.Printf("SendPatch: sending patch between %q and %q for %q", params.ShaFrom, params.ShaTo, r.URL.Path)
+
+	gitRange := fmt.Sprintf("%v...%v", params.ShaFrom, params.ShaTo)
+	gitPatchCmd := gitCommand("", "git", "--git-dir="+params.RepoPath, "format-patch", gitRange, "--stdout")
+
+	stdout, err := gitPatchCmd.StdoutPipe()
+	if err != nil {
+		helper.Fail500(w, fmt.Errorf("SendPatch: create stdout pipe: %v", err))
+		return
+	}
+
+	if err := gitPatchCmd.Start(); err != nil {
+		helper.Fail500(w, fmt.Errorf("SendPatch: start %v: %v", gitPatchCmd, err))
+		return
+	}
+	defer helper.CleanUpProcessGroup(gitPatchCmd)
+
+	w.Header().Del("Content-Length")
+	if _, err := io.Copy(w, stdout); err != nil {
+		helper.LogError(fmt.Errorf("SendPatch: copy %v stdout: %v", gitPatchCmd, err))
+		return
+	}
+	if err := gitPatchCmd.Wait(); err != nil {
+		helper.LogError(fmt.Errorf("SendPatch: wait for %v: %v", gitPatchCmd, err))
+		return
+	}
+}

internal/upstream/routes.go

@@ -49,6 +49,7 @@ func (u *Upstream) configureRoutes() {
 		git.SendArchive,
 		git.SendBlob,
 		git.SendDiff,
+		git.SendPatch,
 	)
 
 	u.Routes = []route{

main_test.go

@@ -665,6 +665,51 @@ func TestGetGitDiff(t *testing.T) {
 	}
 }
 
+func TestGetGitPatch(t *testing.T) {
+	fromSha := "be93687618e4b132087f430a4d8fc3a609c9b77c"
+	toSha := "54fcc214b94e78d7a41a9a8fe6d87a5e59500e51"
+	headerKey := http.CanonicalHeaderKey("Gitlab-Workhorse-Send-Data")
+
+	ts := testhelper.TestServerWithHandler(regexp.MustCompile(`.`), func(w http.ResponseWriter, r *http.Request) {
+		responseJSON := fmt.Sprintf(`{"RepoPath":"%s","ShaFrom":"%s","ShaTo":"%s"}`, path.Join(testRepoRoot, testRepo), fromSha, toSha)
+		encodedJSON := base64.StdEncoding.EncodeToString([]byte(responseJSON))
+		w.Header().Set(headerKey, "git-format-patch:"+encodedJSON)
+		return
+	})
+	defer ts.Close()
+
+	ws := startWorkhorseServer(ts.URL)
+	defer ws.Close()
+
+	resourcePath := "/something"
+	resp, err := http.Get(ws.URL + resourcePath)
+	if err != nil {
+		t.Error(err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		t.Errorf("GET %q: expected 200, got %d", resourcePath, resp.StatusCode)
+	}
+	if len(resp.Header[headerKey]) != 0 {
+		t.Fatalf("Unexpected response header: %s: %q", headerKey, resp.Header.Get(headerKey))
+	}
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !strings.HasPrefix(string(body), "From 54fcc214b94e78d7a41a9a8fe6d87a5e59500e51 Mon Sep 17 00:00:00 2001") {
+		t.Fatalf("Expected: From 54fcc214b94e78d7a41a9a8fe6d87a5e59500e51 Mon Sep 17 00:00:00 2001, got: %v", body)
+	}
+
+	bodyLengthBytes := len(body)
+	if bodyLengthBytes != 449 {
+		t.Fatal("Expected the body to consist of 449 bytes, got %v", bodyLengthBytes)
+	}
+}
+
 func setupStaticFile(fpath, content string) error {
 	cwd, err := os.Getwd()
 	if err != nil {