func main()

in example/flow/memory_adaptive/memory_adaptive_qps_example.go [32:99]
50 lines of code
6 McCabe index (conditional complexity)

func main() {
	// We should initialize Sentinel first.
	conf := config.NewDefaultConfig()
	// for testing, logging output to console
	conf.Sentinel.Log.Logger = logging.NewConsoleLogger()
	// use mock memory usage to replace actual memory usage, so close memory collector
	conf.Sentinel.Stat.System.CollectIntervalMs = 0
	conf.Sentinel.Stat.System.CollectMemoryIntervalMs = 0

	err := sentinel.InitWithConfig(conf)
	if err != nil {
		log.Fatal(err)
	}

	_, err = flow.LoadRules([]*flow.Rule{
		{
			Resource:               resName,
			TokenCalculateStrategy: flow.MemoryAdaptive,
			ControlBehavior:        flow.Reject,
			StatIntervalInMs:       1000,
			LowMemUsageThreshold:   1000,
			HighMemUsageThreshold:  100,
			// bytes
			MemLowWaterMarkBytes:  1024,
			MemHighWaterMarkBytes: 2048,
		},
	})
	if err != nil {
		log.Fatalf("Unexpected error: %+v", err)
		return
	}

	// mock memory usage is 1000 bytes, so QPS threshold should be 1000
	system_metric.SetSystemMemoryUsage(999)
	ch := make(chan struct{})
	for i := 0; i < 10; i++ {
		go func() {
			for {
				e, b := sentinel.Entry(resName, sentinel.WithTrafficType(base.Inbound))
				if b != nil {
					// Blocked. We could get the block reason from the BlockError.
					time.Sleep(time.Duration(rand.Uint64()%2) * time.Millisecond)
				} else {
					// Passed, wrap the logic here.
					time.Sleep(time.Duration(rand.Uint64()%2) * time.Millisecond)
					// Be sure the entry is exited finally.
					e.Exit()
				}
			}
		}()
	}

	// Simulate a scenario in which flow rules are updated concurrently
	go func() {
		time.Sleep(time.Second * 5)
		// mock memory usage is 1536 bytes, so QPS threshold should be 550
		system_metric.SetSystemMemoryUsage(1536)

		time.Sleep(time.Second * 5)
		// mock memory usage is 1536 bytes, so QPS threshold should be 100
		system_metric.SetSystemMemoryUsage(2048)

		time.Sleep(time.Second * 5)
		// mock memory usage is 1536 bytes, so QPS threshold should be 100
		system_metric.SetSystemMemoryUsage(100000)
	}()
	<-ch
}