DegradeSlot 降级插槽

 

新增降级规则
熔断时长：open状态持续时长

DegradeSlot

com.alibaba.csp.sentinel.slots.block.degrade.DegradeSlot#performChecking
慢调用
ResponseTimeCircuitBreaker
异常调用
ExceptionCircuitBreaker

com.alibaba.csp.sentinel.slots.block.degrade.circuitbreaker.AbstractCircuitBreaker#tryPass

 

进入Entry（资源）后，执行exit后，进入whenTerminate方法

 

是否到达熔断时长的某个时刻点，this.retryTimeoutArrived()
到了就进行half-open
com.alibaba.csp.sentinel.slots.block.degrade.circuitbreaker.AbstractCircuitBreaker#notifyObservers
监督状态变化
com.alibaba.csp.sentinel.slots.block.degrade.circuitbreaker.CircuitBreakerStateChangeObserver

放入：this.exitHandlers.add(handler);
最后被方法执行
com.alibaba.csp.sentinel.CtEntry#callExitHandlersAndCleanUp

 

com.alibaba.csp.sentinel.slots.block.degrade.DegradeSlot#exit
得到当前资源

com.alibaba.csp.sentinel.slots.block.degrade.circuitbreaker.ResponseTimeCircuitBreaker#onRequestComplete
统计慢调用数量 counter.slowCount.add(1L);、异常数

com.alibaba.csp.sentinel.slots.block.degrade.circuitbreaker.ResponseTimeCircuitBreaker#handleStateChangeWhenThresholdExceeded
三种状态的切换
half-open ===> open
open ===> close
close ===> close