mirror of
https://github.com/crazybber/go-pattern-examples.git
synced 2024-11-22 20:06:02 +03:00
93 lines
2.3 KiB
Go
93 lines
2.3 KiB
Go
/*
|
||
* @Description: https://github.com/crazybber
|
||
* @Author: Edward
|
||
* @Date: 2020-05-10 22:00:58
|
||
* @Last Modified by: Edward
|
||
* @Last Modified time: 2020-05-22 16:44:57
|
||
*/
|
||
|
||
package circuit
|
||
|
||
import (
|
||
"errors"
|
||
"fmt"
|
||
"sync"
|
||
"time"
|
||
)
|
||
|
||
////////////////////////////////
|
||
///使用HTTP请求的例子
|
||
//每个搜索引擎时时刻刻都会遇到超大规模的请求的流量.
|
||
//这里演示一个复杂一点的例子，同时使用Option 模式
|
||
|
||
//ErrServiceUnavailable for error
|
||
var (
|
||
ErrTooManyRequests = errors.New("too many requests")
|
||
ErrServiceUnavailable = errors.New("service unavailable")
|
||
FailureThreshold = 10 //最大失败次数--->失败阈值
|
||
)
|
||
|
||
// 默认的超时时间
|
||
const (
|
||
defaultTimeout = time.Second * 30
|
||
defaultSuccessThreshold = 2
|
||
)
|
||
|
||
////////////////////////////////
|
||
//way 2 对象式断路器
|
||
// 高级模式
|
||
////////////////////////////////
|
||
|
||
//RequestBreaker for protection
|
||
type RequestBreaker struct {
|
||
options Options
|
||
mutex sync.Mutex
|
||
state OperationState //断路器的当前状态
|
||
generation uint64
|
||
counts ICounter
|
||
}
|
||
|
||
//NewRequestBreaker return a breaker
|
||
func NewRequestBreaker(opts ...Option) *RequestBreaker {
|
||
|
||
defaultOptions := Options{
|
||
Name: "defaultBreakerName",
|
||
Expiry: time.Now().Add(time.Second * 20),
|
||
Interval: time.Second * 2, // interval to check status
|
||
Timeout: time.Second * 60, //default to 60 seconds
|
||
MaxRequests: 5,
|
||
WhenToBreak: func(counts counters) bool { return counts.ConsecutiveFailures > 2 },
|
||
OnStateChanged: func(name string, fromPre State, toCurrent State) {},
|
||
}
|
||
|
||
for _, setOption := range opts {
|
||
setOption(&defaultOptions)
|
||
|
||
}
|
||
|
||
return &RequestBreaker{
|
||
options: defaultOptions,
|
||
counts: &counters{},
|
||
generation: 0,
|
||
}
|
||
}
|
||
|
||
// Do the given requested work if the RequestBreaker accepts it.
|
||
// Do returns an error instantly if the RequestBreaker rejects the request.
|
||
// Otherwise, Execute returns the result of the request.
|
||
// 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() (interface{}, error)) (interface{}, error) {
|
||
|
||
//before
|
||
fmt.Println("before do : request:", rb.counts.Total())
|
||
|
||
//handle status
|
||
|
||
//do work from requested user
|
||
result, err := work()
|
||
|
||
fmt.Println("after do : request:", rb.counts.Total())
|
||
|
||
return result, err
|
||
}
|