Respond to webhook deliveries in under 3 seconds.

src/pages.go

@@ -397,6 +397,10 @@ func deletePage(w http.ResponseWriter, r *http.Request) error {
 }
 
 func postPage(w http.ResponseWriter, r *http.Request) error {
+	// Start a timer for the request timeout immediately.
+	requestTimeout := 3 * time.Second
+	requestTimer := time.NewTimer(requestTimeout)
+
 	auth, err := AuthorizeUpdateFromRepository(r)
 	if err != nil {
 		return err
@@ -414,8 +418,6 @@ func postPage(w http.ResponseWriter, r *http.Request) error {
 
 	webRoot := makeWebRoot(host, projectName)
 
-	isGitHub := strings.Contains(r.Header.Get("User-Agent"), "GitHub-Hookshot")
-
 	eventName := ""
 	for _, header := range []string{
 		"X-Forgejo-Event",
@@ -465,7 +467,7 @@ func postPage(w http.ResponseWriter, r *http.Request) error {
 
 	if event.Ref != fmt.Sprintf("refs/heads/%s", auth.branch) {
 		code := http.StatusUnauthorized
-		if isGitHub {
+		if strings.Contains(r.Header.Get("User-Agent"), "GitHub-Hookshot") {
 			// GitHub has no way to restrict branches for a webhook, and responding with 401
 			// for every non-pages branch makes the "Recent Deliveries" tab look awful.
 			code = http.StatusOK
@@ -481,34 +483,23 @@ func postPage(w http.ResponseWriter, r *http.Request) error {
 		return err
 	}
 
-	updateCtx := r.Context()
-	if isGitHub {
-		updateCtx = context.Background()
-	}
-
-	resultChan := make(chan UpdateResult, 1)
+	resultChan := make(chan UpdateResult)
 	go func(ctx context.Context) {
-		defer close(resultChan)
-
 		ctx, cancel := context.WithTimeout(ctx, time.Duration(config.Limits.UpdateTimeout))
 		defer cancel()
 
 		result := UpdateFromRepository(ctx, webRoot, repoURL, auth.branch)
 		resultChan <- result
 		reportSiteUpdate("webhook", &result)
-	}(updateCtx)
+	}(context.Background())
 
 	var result UpdateResult
-	if isGitHub {
-		select {
-		case result = <-resultChan:
-		case <-time.After(5 * time.Second):
-			w.WriteHeader(http.StatusAccepted)
-			fmt.Fprintf(w, "updating (taking longer than 5 seconds)")
-			return nil
-		}
-	} else {
-		result = <-resultChan
+	select {
+	case result = <-resultChan:
+	case <-requestTimer.C:
+		w.WriteHeader(http.StatusAccepted)
+		fmt.Fprintf(w, "updating (taking longer than %s)", requestTimeout)
+		return nil
 	}
 
 	switch result.outcome {