Function TestThrottlingMultipleConcurrentRequests

registry/cache/cache_test.go:353–418

TestThrottlingMultipleConcurrentRequests verifies that throttling works correctly with multiple concurrent requests when there's no stale cache

(t *testing.T)

// TestThrottlingMultipleConcurrentRequests verifies that throttling works
// correctly with multiple concurrent requests when there's no stale cache
func TestThrottlingMultipleConcurrentRequests(t *testing.T) {
	mock := &mockRegistry{
		err:   errors.New("etcd overloaded"),
		delay: 50 * time.Millisecond,
	}

	c := New(mock, func(o *Options) {
		o.TTL = time.Minute
		o.MinimumRetryInterval = 1 * time.Second
		o.Logger = logger.DefaultLogger
	}).(*cache)

	// First batch - all concurrent requests should result in single call (singleflight)
	const concurrency = 20
	var wg sync.WaitGroup
	wg.Add(concurrency)

	for i := 0; i < concurrency; i++ {
		go func() {
			defer wg.Done()
			c.GetService("test.service")
		}()
	}

	wg.Wait()

	callCount1 := mock.getCallCount()
	if callCount1 != 1 {
		t.Errorf("Expected 1 call (singleflight), got %d", callCount1)
	}

	// Second batch immediately after - should all be throttled (no new calls)
	wg.Add(concurrency)
	for i := 0; i < concurrency; i++ {
		go func() {
			defer wg.Done()
			c.GetService("test.service")
		}()
	}

	wg.Wait()

	callCount2 := mock.getCallCount()
	if callCount2 != 1 {
		t.Errorf("Expected throttling (still 1 call), got %d", callCount2)
	}

	// Wait for retry interval
	time.Sleep(1100 * time.Millisecond)

	// Third batch - should result in one more call
	wg.Add(concurrency)
	for i := 0; i < concurrency; i++ {
		go func() {
			defer wg.Done()
			c.GetService("test.service")
		}()
	}