[WIP] circuit_breaker

gomore/06_circuit_breaker/README.md

@@ -8,6 +8,10 @@ Circuit Breaker Pattern 也叫断路器模式，断路器设计模式是故障
 
 ![熔断器状态机](../../images/breaker-state-machine.png)
 
+状态变化流：
+
+![状态变化流](../../images/breaker-state-machine-flow.png)
+
 一些关键角色：
 
 ## Operation Counter 操作计数器

gomore/06_circuit_breaker/breaker_options.go

@@ -19,22 +19,47 @@ func SetName(name string) Option {
 	}
 }
 
-//SetExpiry of breaker
-func SetExpiry(expiry time.Time) Option {
+//Interval of breaker
+func Interval(interval time.Duration) Option {
+	return func(opts *Options) {
+		opts.Interval = interval
+	}
+}
+
+//Timeout of breaker
+func Timeout(timeout time.Duration) Option {
+	return func(opts *Options) {
+		opts.Timeout = timeout
+	}
+}
+
+// MaxRequests is the maximum number of requests allowed to pass through
+// when the CircuitBreaker is half-open.
+// If MaxRequests is 0, the CircuitBreaker allows only 1 request.
+
+//MaxRequests of breaker
+func MaxRequests(maxRequests uint32) Option {
+	return func(opts *Options) {
+		opts.MaxRequests = maxRequests
+	}
+}
+
+//Expiry of breaker
+func Expiry(expiry time.Time) Option {
 	return func(opts *Options) {
 		opts.Expiry = expiry
 	}
 }
 
-//SetStateChangedHandle set handle of ChangedHandle
-func SetStateChangedHandle(handler StateChangedEventHandler) Option {
+//OnStateChanged set handle of ChangedHandle
+func OnStateChanged(handler StateChangedEventHandler) Option {
 	return func(opts *Options) {
 		opts.OnStateChanged = handler
 	}
 }
 
-//SetReadyToTrip check traffic state ,to see if request can go
-func SetReadyToTrip(readyToGo StateCheckerHandler) Option {
+//ReadyToTrip check traffic state ,to see if request can go
+func ReadyToTrip(readyToGo StateCheckerHandler) Option {
 	return func(opts *Options) {
 		opts.ReadyToTrip = readyToGo
 	}

gomore/06_circuit_breaker/circuit_breaker.go

@@ -5,7 +5,7 @@ package circuit
  * @Author: Edward
  * @Date: 2020-05-10 22:00:58
  * @Last Modified by: Edward
- * @Last Modified time: 2020-05-11 11:57:21
+ * @Last Modified time: 2020-05-11 17:46:20
  */
 
 import (
@@ -42,7 +42,7 @@ type RequestBreaker struct {
 	mutex      sync.Mutex
 	state      State
 	generation uint64
-	counts     Counter
+	counts     ICounter
 }
 
 //NewRequestBreaker return a breaker
@@ -52,7 +52,7 @@ func NewRequestBreaker(opts ...Option) *RequestBreaker {
 		Name:           "defaultBreakerName",
 		Expiry:         time.Now().Add(time.Second * 20),
 		Interval:       time.Second * 2,
-		Timeout:        time.Second * 5,
+		Timeout:        time.Second * 60, //default to 60 seconds
 		MaxRequests:    5,
 		ReadyToTrip:    func(counts counters) bool { return true },
 		OnStateChanged: func(name string, from State, to State) {},
@@ -83,8 +83,8 @@ const (
 //Circuit of action stream
 type Circuit func(context.Context) error
 
-//Counter interface
-type Counter interface {
+//ICounter interface
+type ICounter interface {
 	Count(State)
 	ConsecutiveFailures() uint32
 	LastActivity() time.Time
@@ -92,6 +92,7 @@ type Counter interface {
 }
 
 type counters struct {
+	Requests     uint32
 	state        State
 	lastActivity time.Time
 	counts       uint32 //counts of failures
@@ -115,7 +116,7 @@ func (c *counters) Reset() {
 }
 
 //NewCounter New Counter for Circuit Breaker
-func NewCounter() Counter {
+func NewCounter() ICounter {
 	return &counters{}
 }
 
@@ -127,7 +128,7 @@ func Breaker(c Circuit, failureThreshold uint32) Circuit {
 	return func(ctx context.Context) error {
 		if cnt.ConsecutiveFailures() >= failureThreshold {
 
-			canRetry := func(cnt Counter) bool {
+			canRetry := func(cnt ICounter) bool {
 				backoffLevel := cnt.ConsecutiveFailures() - failureThreshold
 
 				// Calculates when should the circuit breaker resume propagating requests