Function TestResponseRetryHeader

modules/caddyhttp/reverseproxy/retries_test.go:335–382

TestResponseRetryHeader verifies that response header matching triggers retries via a CEL expression checking {rp.header.*}

(t *testing.T)

// TestResponseRetryHeader verifies that response header matching triggers
// retries via a CEL expression checking {rp.header.*}
func TestResponseRetryHeader(t *testing.T) {
	// Bad upstream: returns 200 but with X-Upstream-Retry header
	badServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("X-Upstream-Retry", "true")
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("bad"))
	}))
	t.Cleanup(badServer.Close)

	// Good upstream: returns 200 without retry header
	goodServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("good"))
	}))
	t.Cleanup(goodServer.Close)

	retryMatch := caddyhttp.MatcherSets{
		caddyhttp.MatcherSet{
			newExpressionMatcher(t, `{http.reverse_proxy.header.X-Upstream-Retry} == "true"`),
		},
	}

	// RoundRobin picks index 1 first, then 0
	upstreams := []*Upstream{
		{Host: new(Host), Dial: goodServer.Listener.Addr().String()},
		{Host: new(Host), Dial: badServer.Listener.Addr().String()},
	}

	h := minimalHandlerWithRetryMatch(1, retryMatch, upstreams...)

	req := httptest.NewRequest(http.MethodGet, "http://example.com/", nil)
	req = prepareTestRequest(req)
	rec := httptest.NewRecorder()

	err := h.ServeHTTP(rec, req, caddyhttp.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
		return nil
	}))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if rec.Code != http.StatusOK {
		t.Errorf("status: got %d, want %d", rec.Code, http.StatusOK)
	}
	if rec.Body.String() != "good" {
		t.Errorf("body: got %q, want %q (retried to wrong upstream)", rec.Body.String(), "good")
	}
}

// TestResponseRetryNoMatchNoRetry verifies that when no retry_match entries
// match the response, the original response is returned without retrying