Diffs served by workhorse

Purposed of this commit is to trigger CI and hope it doesn't get the
'importing internal packages not allowed' error Im getting while
building.

internal/git/diff.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 diff struct{ senddata.Prefix }
+type diffParams struct {
+	RepoPath string
+	ShaFrom  string
+	ShaTo    string
+}
+
+var SendDiff = &diff{"git-diff:"}
+
+func (d *diff) Inject(w http.ResponseWriter, r *http.Request, sendData string) {
+	var params diffParams
+	if err := d.Unpack(&params, sendData); err != nil {
+		helper.Fail500(w, fmt.Errorf("SendDiff: unpack sendData: %v", err))
+		return
+	}
+
+	log.Printf("SendDiff: sending diff between %q and %q for %q", params.ShaFrom, params.ShaTo, r.URL.Path)
+
+	gitShowCmd := gitCommand("", "git", "--git-dir="+params.RepoPath, "diff", params.ShaFrom, params.ShaTo)
+	stdout, err := gitShowCmd.StdoutPipe()
+	if err != nil {
+		helper.Fail500(w, fmt.Errorf("SendDiff: git diff %q %q stdout: %v", params.ShaFrom, params.ShaTo, err))
+		return
+	}
+	if err := gitShowCmd.Start(); err != nil {
+		helper.Fail500(w, fmt.Errorf("SendDiff: git diff %q %q stdout: %v", params.ShaFrom, params.ShaTo, err))
+		return
+	}
+	defer helper.CleanUpProcessGroup(gitShowCmd)
+
+	if _, err := io.Copy(w, stdout); err != nil {
+		helper.LogError(fmt.Errorf("SendDiff: git diff %q %q stdout: %v", err))
+		return
+	}
+	if err := gitShowCmd.Wait(); err != nil {
+		helper.LogError(fmt.Errorf("SendDiff: git diff %q %q stdout: %v", err))
+		return
+	}
+}

internal/upstream/routes.go

@@ -48,6 +48,7 @@ func (u *Upstream) configureRoutes() {
 		)),
 		git.SendArchive,
 		git.SendBlob,
+		git.SendDiff,
 	)
 
 	u.Routes = []route{