Function TestDelayedLogFlushing

internal/api_test.go:269–330

(t *testing.T)

}

func TestDelayedLogFlushing(t *testing.T) {
	defer restoreEnvVar(logserviceEnvVarKey)()

	testCases := []struct {
		logToLogservice    string
		wantInitialFlushes int32
		wantHeader         string
		wantEndFlushes     int32
	}{
		{logToLogservice: "", wantHeader: "1", wantInitialFlushes: 1, wantEndFlushes: 2}, // default behavior
		{logToLogservice: "1", wantHeader: "1", wantInitialFlushes: 1, wantEndFlushes: 2},
		{logToLogservice: "0", wantHeader: "", wantInitialFlushes: 0, wantEndFlushes: 0},
	}
	for _, tc := range testCases {
		t.Run(fmt.Sprintf("$%s=%q", logserviceEnvVarKey, tc.logToLogservice), func(t *testing.T) {
			f, c, cleanup := setup()
			defer cleanup()
			os.Setenv(logserviceEnvVarKey, tc.logToLogservice)

			path := "/slow_log_" + tc.logToLogservice

			http.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
				logC := WithContext(context.Background(), r)
				Logf(logC, 1, "It's a lovely day.")
				w.WriteHeader(200)
				time.Sleep(1200 * time.Millisecond)
				w.Write(make([]byte, 100<<10)) // write 100 KB to force HTTP flush
			})

			r := &http.Request{
				Method: "GET",
				URL: &url.URL{
					Scheme: "http",
					Path:   path,
				},
				Header: c.req.Header,
				Body:   ioutil.NopCloser(bytes.NewReader(nil)),
			}
			w := httptest.NewRecorder()

			handled := make(chan struct{})
			go func() {
				defer close(handled)
				Middleware(http.DefaultServeMux).ServeHTTP(w, r)
			}()
			// Check that the log flush eventually comes in.
			time.Sleep(1200 * time.Millisecond)
			if got := atomic.LoadInt32(&f.LogFlushes); got != tc.wantInitialFlushes {
				t.Errorf("After 1.2s: f.LogFlushes = %d, want %d", got, tc.wantInitialFlushes)
			}

			<-handled
			const hdr = "X-AppEngine-Log-Flush-Count"
			if got := w.HeaderMap.Get(hdr); got != tc.wantHeader {
				t.Errorf("%s header = %q, want %q", hdr, got, tc.wantHeader)
			}
			if got := atomic.LoadInt32(&f.LogFlushes); got != tc.wantEndFlushes {
				t.Errorf("After HTTP response: f.LogFlushes = %d, want %d", got, tc.wantEndFlushes)