add state handler proc

resiliency/06_circuit_breaker/circuit_breaker_adv.go

@@ -46,7 +46,7 @@ type RequestBreaker struct {
 	mutex      sync.Mutex
 	state      State
 	generation uint64
-	cnter      ICounter
+	cnter      counters
 }
 
 //NewRequestBreaker return a breaker
@@ -69,7 +69,7 @@ func NewRequestBreaker(opts ...Option) *RequestBreaker {
 
 	return &RequestBreaker{
 		options:    defaultOptions,
-		cnter:      &counters{},
+		cnter:      counters{},
 		generation: 0,
 	}
 }
@@ -80,6 +80,8 @@ func NewRequestBreaker(opts ...Option) *RequestBreaker {
 // If a panic occurs in the request, the RequestBreaker handles it as an error and causes the same panic again.
 func (rb *RequestBreaker) Do(work func(ctx context.Context) (interface{}, error)) (interface{}, error) {
 
+	preState := StateUnknown
+
 	//before
 	fmt.Println("before do : request:", rb.cnter.Total())
 	rb.mutex.Lock()
@@ -87,22 +89,14 @@ func (rb *RequestBreaker) Do(work func(ctx context.Context) (interface{}, error)
 	case StateOpen:
 		return nil, ErrTooManyRequests
 	case StateHalfOpen:
-		//do work from requested user
+		//如果是断开状态，并且超时了，转到半开状态，记录
-		//	result, err := work(rb.options.Ctx)
-		// if err != nil {
-		// 	rb.cnter.Count(FailureState)
-		// } else {
-		// 	rb.cnter.Count(SuccessState)
-		// 	return result, nil
-		// }
-
 		if rb.options.Expiry.Before(time.Now()) {
 			rb.state = StateHalfOpen
+			preState = rb.state
 			rb.cnter.Reset()
-			rb.options.OnStateChanged(rb.options.Name, StateOpen, StateHalfOpen)
+
 		}
 
-	case StateClosed:
 	}
 
 	rb.mutex.Unlock()
@@ -111,12 +105,29 @@ func (rb *RequestBreaker) Do(work func(ctx context.Context) (interface{}, error)
 	//do work from requested user
 	result, err := work(rb.options.Ctx)
 
+	rb.mutex.Lock()
+	//失败了
 	if err != nil {
 		rb.cnter.Count(FailureState)
+		//如果是在半开状态下的失败，立即打开开关
+		if rb.state == StateHalfOpen {
+			rb.state = StateOpen //转为打开
+		} else if rb.state == StateClosed {
+			if rb.options.WhenToBreak(rb.cnter) {
+				rb.state = StateOpen //打开开关
+				rb.cnter.Reset()
+			}
+		}
+
 	} else {
 		rb.cnter.Count(SuccessState)
-	}
+		if preState == StateOpen && rb.state == StateHalfOpen {
+			rb.options.OnStateChanged(rb.options.Name, StateOpen, StateHalfOpen)
+		}
 
+	}
+	rb.mutex.Unlock()
+	//after
 	fmt.Println("after do : request:", rb.cnter.Total())
 
 	return result, err