package retry import ( "context" "fmt" "io" "net/http" "net/http/httptest" "net/http/httptrace" "net/textproto" "strings" "testing" "time" "github.com/gorilla/websocket" "github.com/stretchr/testify/assert" "github.com/stretchr/testify/require" ptypes "github.com/traefik/paerser/types" "github.com/traefik/traefik/v3/pkg/config/dynamic" "github.com/traefik/traefik/v3/pkg/testhelpers" ) func TestRetry(t *testing.T) { testCases := []struct { desc string config dynamic.Retry wantRetryAttempts int wantResponseStatus int amountFaultyEndpoints int }{ { desc: "no retry on success", config: dynamic.Retry{Attempts: 5}, wantRetryAttempts: 0, wantResponseStatus: http.StatusOK, amountFaultyEndpoints: 0, }, { desc: "no retry on success with backoff", config: dynamic.Retry{Attempts: 5, InitialInterval: ptypes.Duration(time.Microsecond * 50)}, wantRetryAttempts: 0, wantResponseStatus: http.StatusOK, amountFaultyEndpoints: 0, }, { desc: "no retry when max request attempts is one", config: dynamic.Retry{Attempts: 1}, wantRetryAttempts: 0, wantResponseStatus: http.StatusBadGateway, amountFaultyEndpoints: 1, }, { desc: "no retry when max request attempts is one with backoff", config: dynamic.Retry{Attempts: 1, InitialInterval: ptypes.Duration(time.Microsecond * 50)}, wantRetryAttempts: 0, wantResponseStatus: http.StatusBadGateway, amountFaultyEndpoints: 1, }, { desc: "one retry when one server is faulty", config: dynamic.Retry{Attempts: 2}, wantRetryAttempts: 1, wantResponseStatus: http.StatusOK, amountFaultyEndpoints: 1, }, { desc: "one retry when one server is faulty with backoff", config: dynamic.Retry{Attempts: 2, InitialInterval: ptypes.Duration(time.Microsecond * 50)}, wantRetryAttempts: 1, wantResponseStatus: http.StatusOK, amountFaultyEndpoints: 1, }, { desc: "two retries when two servers are faulty", config: dynamic.Retry{Attempts: 3}, wantRetryAttempts: 2, wantResponseStatus: http.StatusOK, amountFaultyEndpoints: 2, }, { desc: "two retries when two servers are faulty with backoff", config: dynamic.Retry{Attempts: 3, InitialInterval: ptypes.Duration(time.Microsecond * 50)}, wantRetryAttempts: 2, wantResponseStatus: http.StatusOK, amountFaultyEndpoints: 2, }, { desc: "max attempts exhausted delivers the 5xx response", config: dynamic.Retry{Attempts: 3}, wantRetryAttempts: 2, wantResponseStatus: http.StatusBadGateway, amountFaultyEndpoints: 3, }, { desc: "max attempts exhausted delivers the 5xx response with backoff", config: dynamic.Retry{Attempts: 3, InitialInterval: ptypes.Duration(time.Microsecond * 50)}, wantRetryAttempts: 2, wantResponseStatus: http.StatusBadGateway, amountFaultyEndpoints: 3, }, } for _, test := range testCases { test := test t.Run(test.desc, func(t *testing.T) { t.Parallel() retryAttempts := 0 next := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { retryAttempts++ if retryAttempts > test.amountFaultyEndpoints { // calls WroteHeaders on httptrace. _ = r.Write(io.Discard) rw.WriteHeader(http.StatusOK) return } rw.WriteHeader(http.StatusBadGateway) }) retryListener := &countingRetryListener{} retry, err := New(context.Background(), next, test.config, retryListener, "traefikTest") require.NoError(t, err) recorder := httptest.NewRecorder() req := httptest.NewRequest(http.MethodGet, "http://localhost:3000/ok", nil) retry.ServeHTTP(recorder, req) assert.Equal(t, test.wantResponseStatus, recorder.Code) assert.Equal(t, test.wantRetryAttempts, retryListener.timesCalled) }) } } func TestRetryEmptyServerList(t *testing.T) { next := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { rw.WriteHeader(http.StatusServiceUnavailable) }) retryListener := &countingRetryListener{} retry, err := New(context.Background(), next, dynamic.Retry{Attempts: 3}, retryListener, "traefikTest") require.NoError(t, err) recorder := httptest.NewRecorder() req := httptest.NewRequest(http.MethodGet, "http://localhost:3000/ok", nil) retry.ServeHTTP(recorder, req) assert.Equal(t, http.StatusServiceUnavailable, recorder.Code) assert.Equal(t, 0, retryListener.timesCalled) } func TestRetryListeners(t *testing.T) { req := httptest.NewRequest(http.MethodGet, "/", nil) retryListeners := Listeners{&countingRetryListener{}, &countingRetryListener{}} retryListeners.Retried(req, 1) retryListeners.Retried(req, 1) for _, retryListener := range retryListeners { listener := retryListener.(*countingRetryListener) if listener.timesCalled != 2 { t.Errorf("retry listener was called %d time(s), want %d time(s)", listener.timesCalled, 2) } } } func TestMultipleRetriesShouldNotLooseHeaders(t *testing.T) { attempt := 0 expectedHeaderName := "X-Foo-Test-2" expectedHeaderValue := "bar" next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) { headerName := fmt.Sprintf("X-Foo-Test-%d", attempt) rw.Header().Add(headerName, expectedHeaderValue) if attempt < 2 { attempt++ return } // Request has been successfully written to backend trace := httptrace.ContextClientTrace(req.Context()) trace.WroteHeaders() // And we decide to answer to client rw.WriteHeader(http.StatusNoContent) }) retry, err := New(context.Background(), next, dynamic.Retry{Attempts: 3}, &countingRetryListener{}, "traefikTest") require.NoError(t, err) responseRecorder := httptest.NewRecorder() retry.ServeHTTP(responseRecorder, testhelpers.MustNewRequest(http.MethodGet, "http://test", http.NoBody)) headerValue := responseRecorder.Header().Get(expectedHeaderName) // Validate if we have the correct header if headerValue != expectedHeaderValue { t.Errorf("Expected to have %s for header %s, got %s", expectedHeaderValue, expectedHeaderName, headerValue) } // Validate that we don't have headers from previous attempts for i := 0; i < attempt; i++ { headerName := fmt.Sprintf("X-Foo-Test-%d", i) headerValue = responseRecorder.Header().Get("headerName") if headerValue != "" { t.Errorf("Expected no value for header %s, got %s", headerName, headerValue) } } } // countingRetryListener is a Listener implementation to count the times the Retried fn is called. type countingRetryListener struct { timesCalled int } func (l *countingRetryListener) Retried(req *http.Request, attempt int) { l.timesCalled++ } func TestRetryWithFlush(t *testing.T) { next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) { rw.WriteHeader(http.StatusOK) _, err := rw.Write([]byte("FULL ")) if err != nil { http.Error(rw, err.Error(), http.StatusInternalServerError) } rw.(http.Flusher).Flush() _, err = rw.Write([]byte("DATA")) if err != nil { http.Error(rw, err.Error(), http.StatusInternalServerError) } }) retry, err := New(context.Background(), next, dynamic.Retry{Attempts: 1}, &countingRetryListener{}, "traefikTest") require.NoError(t, err) responseRecorder := httptest.NewRecorder() retry.ServeHTTP(responseRecorder, &http.Request{}) assert.Equal(t, "FULL DATA", responseRecorder.Body.String()) } func TestRetryWebsocket(t *testing.T) { testCases := []struct { desc string maxRequestAttempts int expectedRetryAttempts int expectedResponseStatus int expectedError bool amountFaultyEndpoints int }{ { desc: "Switching ok after 2 retries", maxRequestAttempts: 3, expectedRetryAttempts: 2, amountFaultyEndpoints: 2, expectedResponseStatus: http.StatusSwitchingProtocols, }, { desc: "Switching failed", maxRequestAttempts: 2, expectedRetryAttempts: 1, amountFaultyEndpoints: 2, expectedResponseStatus: http.StatusBadGateway, expectedError: true, }, } for _, test := range testCases { test := test t.Run(test.desc, func(t *testing.T) { t.Parallel() retryAttempts := 0 next := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { retryAttempts++ if retryAttempts > test.amountFaultyEndpoints { upgrader := websocket.Upgrader{} _, err := upgrader.Upgrade(rw, r, nil) if err != nil { http.Error(rw, err.Error(), http.StatusInternalServerError) } return } rw.WriteHeader(http.StatusBadGateway) }) retryListener := &countingRetryListener{} retryH, err := New(context.Background(), next, dynamic.Retry{Attempts: test.maxRequestAttempts}, retryListener, "traefikTest") require.NoError(t, err) retryServer := httptest.NewServer(retryH) url := strings.Replace(retryServer.URL, "http", "ws", 1) _, response, err := websocket.DefaultDialer.Dial(url, nil) if !test.expectedError { require.NoError(t, err) } assert.Equal(t, test.expectedResponseStatus, response.StatusCode) assert.Equal(t, test.expectedRetryAttempts, retryListener.timesCalled) }) } } // This test is an adapted version of net/http/httputil.Test1xxResponses test. func Test1xxResponses(t *testing.T) { next := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { h := w.Header() h.Add("Link", "; rel=preload; as=style") h.Add("Link", "; rel=preload; as=script") w.WriteHeader(http.StatusEarlyHints) h.Add("Link", "; rel=preload; as=script") w.WriteHeader(http.StatusProcessing) _, _ = w.Write([]byte("Hello")) }) retryListener := &countingRetryListener{} retry, err := New(context.Background(), next, dynamic.Retry{Attempts: 1}, retryListener, "traefikTest") require.NoError(t, err) server := httptest.NewServer(retry) t.Cleanup(server.Close) frontendClient := server.Client() checkLinkHeaders := func(t *testing.T, expected, got []string) { t.Helper() if len(expected) != len(got) { t.Errorf("Expected %d link headers; got %d", len(expected), len(got)) } for i := range expected { if i >= len(got) { t.Errorf("Expected %q link header; got nothing", expected[i]) continue } if expected[i] != got[i] { t.Errorf("Expected %q link header; got %q", expected[i], got[i]) } } } var respCounter uint8 trace := &httptrace.ClientTrace{ Got1xxResponse: func(code int, header textproto.MIMEHeader) error { switch code { case http.StatusEarlyHints: checkLinkHeaders(t, []string{"; rel=preload; as=style", "; rel=preload; as=script"}, header["Link"]) case http.StatusProcessing: checkLinkHeaders(t, []string{"; rel=preload; as=style", "; rel=preload; as=script", "; rel=preload; as=script"}, header["Link"]) default: t.Error("Unexpected 1xx response") } respCounter++ return nil }, } req, _ := http.NewRequestWithContext(httptrace.WithClientTrace(context.Background(), trace), http.MethodGet, server.URL, nil) res, err := frontendClient.Do(req) assert.Nil(t, err) defer res.Body.Close() if respCounter != 2 { t.Errorf("Expected 2 1xx responses; got %d", respCounter) } checkLinkHeaders(t, []string{"; rel=preload; as=style", "; rel=preload; as=script", "; rel=preload; as=script"}, res.Header["Link"]) body, _ := io.ReadAll(res.Body) if string(body) != "Hello" { t.Errorf("Read body %q; want Hello", body) } assert.Equal(t, 0, retryListener.timesCalled) }