Browser: Return 408 status code on readiness timeout (#862)

Author: macabu

pkg/api/render.go

@@ -237,7 +237,8 @@ func HandleGetRender(browser *service.BrowserService) http.Handler {
 			span.SetStatus(codes.Error, "rendering failed")
 			span.RecordError(err)
 			if errors.Is(err, context.DeadlineExceeded) ||
-				errors.Is(err, context.Canceled) {
+				errors.Is(err, context.Canceled) ||
+				errors.Is(err, service.ErrBrowserReadinessTimeout) {
 				http.Error(w, "Request timed out", http.StatusRequestTimeout)
 				return
 			} else if errors.Is(err, service.ErrInvalidBrowserOption) {

pkg/service/browser.go

@@ -77,7 +77,10 @@ var (
 	}, []string{"mime_type"})
 )
 
-var ErrInvalidBrowserOption = errors.New("invalid browser option")
+var (
+	ErrInvalidBrowserOption    = errors.New("invalid browser option")
+	ErrBrowserReadinessTimeout = errors.New("timed out waiting for readiness")
+)
 
 type BrowserService struct {
 	cfg       config.BrowserConfig
@@ -1001,8 +1004,8 @@ func waitForReady(browserCtx context.Context, cfg config.BrowserConfig) chromedp
 				span.SetStatus(codes.Error, "context completed before readiness detected")
 				return ctx.Err()
 			case <-readinessTimeout:
-				span.SetStatus(codes.Error, "timed out waiting for readiness")
-				return fmt.Errorf("timed out waiting for readiness")
+				span.SetStatus(codes.Error, ErrBrowserReadinessTimeout.Error())
+				return ErrBrowserReadinessTimeout
 
 			case <-time.After(cfg.ReadinessIterationInterval):
 				// Continue with the rest of the code; this is waiting for the next time we can do work.

tests/acceptance/expected_failures_test.go

@@ -98,3 +98,23 @@ func TestInvalidQueryParameters(t *testing.T) {
 		})
 	}
 }
+
+func TestBrowserTimeout(t *testing.T) {
+	t.Parallel()
+
+	t.Run("if the browser readiness timeout is exceeded, it returns a 408 status code", func(t *testing.T) {
+		t.Parallel()
+
+		// extremely low that no request could ever be server in the alloted time
+		svc := StartImageRenderer(t, WithEnv("BROWSER_READINESS_TIMEOUT", "1ns"))
+
+		req, err := http.NewRequestWithContext(t.Context(), http.MethodGet, svc.HTTPEndpoint+"/render?url=http://localhost:8081/&encoding=pdf", nil)
+		require.NoError(t, err, "could not construct HTTP request to /render")
+		req.Header.Set("Accept", "application/pdf")
+		req.Header.Set("X-Auth-Token", "-")
+
+		resp, err := http.DefaultClient.Do(req)
+		require.NoError(t, err, "could not make HTTP request to /render")
+		require.Equal(t, http.StatusRequestTimeout, resp.StatusCode, "expected HTTP 408 Request Timeout from /render")
+	})
+}