finish the simple circuit_breaker

resiliency/06_circuit_breaker/circuit_breaker.go

@@ -3,7 +3,7 @@
  * @Author: Edward
  * @Date: 2020-05-10 22:00:58
  * @Last Modified by: Edward
- * @Last Modified time: 2020-05-22 14:22:42
+ * @Last Modified time: 2020-05-22 16:44:57
  */
 
 package circuit
@@ -34,7 +34,8 @@ const (
 )
 
 ////////////////////////////////
-//way 1 对象式断路器
+//way 2 对象式断路器
+// 高级模式
 ////////////////////////////////
 
 //RequestBreaker for protection
@@ -80,6 +81,8 @@ func (rb *RequestBreaker) Do(work func() (interface{}, error)) (interface{}, err
 	//before
 	fmt.Println("before do : request:", rb.counts.Total())
 
+	//handle status
+
 	//do work from requested user
 	result, err := work()
 

resiliency/06_circuit_breaker/circuit_breaker_test.go

@@ -3,7 +3,7 @@
  * @Author: Edward
  * @Date: 2020-05-11 10:55:28
  * @Last Modified by: Edward
- * @Last Modified time: 2020-05-21 14:08:53
+ * @Last Modified time: 2020-05-22 16:37:21
  */
 
 package circuit
@@ -12,13 +12,14 @@ import (
 	"context"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"net/http"
 	"testing"
 )
 
 var breaker *RequestBreaker
 
-func TestBasicBreaker(t *testing.T) {
+func TestObjectBreaker(t *testing.T) {
 
 	jobToDo := func() (interface{}, error) {
 		resp, err := http.Get("https://bing.com/robots.txt")
@@ -72,6 +73,8 @@ func TestFunctionalBreaker(t *testing.T) {
 	params := context.TODO()
 
 	// do the job as usually
-	circuitWork(params)
+	res := circuitWork(params)
+
+	log.Print("\nresult:", res)
 
 }

resiliency/06_circuit_breaker/circuit_counter.go

@@ -3,7 +3,7 @@
  * @Author: Edward
  * @Date: 2020-05-22 12:41:54
  * @Last Modified by: Edward
- * @Last Modified time: 2020-05-22 14:21:00
+ * @Last Modified time: 2020-05-22 16:47:37
  */
 
 package circuit
@@ -42,7 +42,6 @@ type counters struct {
 	Requests             uint32 //连续的请求次数
 	lastState            OperationState
 	lastActivity         time.Time
-	counts               uint32 //counts of failures
 	TotalFailures        uint32
 	TotalSuccesses       uint32
 	ConsecutiveSuccesses uint32

resiliency/06_circuit_breaker/circuit_func_closure.go

@@ -3,7 +3,7 @@
  * @Author: Edward
  * @Date: 2020-05-22 12:42:34
  * @Last Modified by: Edward
- * @Last Modified time: 2020-05-22 14:35:00
+ * @Last Modified time: 2020-05-22 16:48:56
  */
 
 package circuit
@@ -16,7 +16,7 @@ import (
 ////////////////////////////////
 //way 2 简单的函数式断路器
 // 一个func实例作为一个Breaker 允许多个worker(即goroutine)同时访问
-// 理论上讲也需要考虑同步问题
+// 当前简单场景下，只考虑单个worker情况下的连续请求
 // 当前的设计思路，非常简单：
 //     1、不考虑三种状态之间的转换，只靠两种状态，电路打开与电路关闭
 //     2、当累计失败到达一定失败次数就端开请求(打开电路)，并延迟一定的时间再允许请求
@@ -30,11 +30,44 @@ const (
 	SuccessState
 )
 
+type simpleCounter struct {
+	lastState            OperationState
+	lastActivity         time.Time
+	ConsecutiveSuccesses uint32
+	ConsecutiveFailures  uint32
+}
+
+func (c *simpleCounter) LastActivity() time.Time {
+	return c.lastActivity
+}
+
+func (c *simpleCounter) Reset() {
+	ct := &simpleCounter{}
+	ct.lastActivity = c.lastActivity
+	ct.lastState = UnknownState
+	c = ct
+}
+
+//Count the failure and success
+func (c *simpleCounter) Count(statue OperationState) {
+
+	switch statue {
+	case FailureState:
+		c.ConsecutiveFailures++
+	case SuccessState:
+		c.ConsecutiveSuccesses++
+	}
+	c.lastActivity = time.Now() //更新活动时间
+	c.lastState = statue
+	//handle status change
+}
+
 //Circuit of action stream,this is actually to do something.
 //Circuit hold the really action
 type Circuit func(context.Context) error
 
-var canRetry = func(cnt counters, failureThreshold uint32) bool {
+//失败达到阈值后,过两秒重试
+var canRetry = func(cnt simpleCounter, failureThreshold uint32) bool {
 	backoffLevel := cnt.ConsecutiveFailures - failureThreshold
 	// Calculates when should the circuit breaker resume propagating requests
 	// to the service
@@ -42,25 +75,30 @@ var canRetry = func(cnt counters, failureThreshold uint32) bool {
 	return time.Now().After(shouldRetryAt)
 }
 
-//Breaker return a closure wrapper to hold request
+//Breaker return a closure wrapper to hold Circuit Request
 func Breaker(c Circuit, failureThreshold uint32) Circuit {
 
 	//闭包内部的全局计数器 和状态标志
-	cnt := counters{}
+	cnt := simpleCounter{}
 
 	//ctx can be used hold parameters
 	return func(ctx context.Context) error {
 
+		//阻止请求
 		if cnt.ConsecutiveFailures >= failureThreshold {
 			if !canRetry(cnt, failureThreshold) {
 				// Fails fast instead of propagating requests to the circuit since
 				// not enough time has passed since the last failure to retry
 				return ErrServiceUnavailable
 			}
+			//reset mark for failures
+			cnt.ConsecutiveFailures = 0
 		}
+
 		// Unless the failure threshold is exceeded the wrapped service mimics the
 		// old behavior and the difference in behavior is seen after consecutive failures
 		if err := c(ctx); err != nil {
+			//连续失败会增大backoff 时间
 			cnt.Count(FailureState)
 			return err
 		}