add a state check

resiliency/06_circuit_breaker/README.md

@@ -20,7 +20,7 @@ Circuit Breaker Pattern 也叫断路器模式，断路器设计模式是故障
 
 ## Circuit Breaker 断路器
 
-如果电路连续故障超过指定的阈值，它将返回一个快速错误，一段时间后，它会重试请求并记录它。
+电路连续故障，并且超过指定的阈值，它将返回一个快速错误，一段时间后，才会重试请求。
 
 ## Context
 

resiliency/06_circuit_breaker/circuit_breaker_adv.go

@@ -10,11 +10,10 @@ package circuit
 
 import (
 	"context"
-	"context
-	"erros"
+	"errors"
 	"fmt"
 	"sync"
-	time"
+	"time"
 )
 
 ////////////////////////////////
@@ -87,10 +86,29 @@ func (rb *RequestBreaker) Do(work func(ctx context.Context) (interface{}, error)
 	rb.mutex.Lock()
 	//handle status of Open to HalfOpen
 	if rb.state == StateOpen && rb.options.Expiry.Before(time.Now()) {
-
+		rb.state = StateHalfOpen
+		rb.cnter.Reset()
+		rb.options.OnStateChanged(rb.options.Name, StateOpen, StateHalfOpen)
 	}
 	rb.mutex.Unlock()
 
+	switch rb.state {
+	case StateOpen:
+		return nil, ErrTooManyRequests
+	case StateHalfOpen:
+		//do work from requested user
+		result, err := work(rb.options.Ctx)
+		if err != nil {
+			rb.cnter.Count(FailureState)
+
+		} else {
+			rb.cnter.Count(SuccessState)
+			return result, nil
+		}
+
+	case StateClosed:
+	}
+
 	//do work from requested user
 	result, err := work(rb.options.Ctx)