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https://github.com/crazybber/go-pattern-examples.git
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add an options
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42
gomore/06_circuit_breaker/breaker_options.go
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42
gomore/06_circuit_breaker/breaker_options.go
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@ -0,0 +1,42 @@
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package circuit
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import "time"
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//Options for breaker
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type Options struct {
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Name string
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Expiry time.Time
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Interval time.Duration
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Timeout time.Duration
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MaxRequests uint32
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ReadyToTrip StateCheckerHandler
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OnStateChanged StateChangedEventHandler
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}
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//SetName of breaker
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func SetName(name string) Option {
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return func(opts *Options) {
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opts.Name = name
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}
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}
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//SetExpiry of breaker
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func SetExpiry(expiry time.Time) Option {
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return func(opts *Options) {
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opts.Expiry = expiry
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}
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}
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//SetStateChangedHandle set handle of ChangedHandle
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func SetStateChangedHandle(handler StateChangedEventHandler) Option {
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return func(opts *Options) {
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opts.OnStateChanged = handler
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}
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}
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//SetReadyToTrip check traffic state ,to see if request can go
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func SetReadyToTrip(readyToGo StateCheckerHandler) Option {
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return func(opts *Options) {
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opts.ReadyToTrip = readyToGo
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}
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}
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@ -1,11 +1,25 @@
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package circuit
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/*
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* @Description: https://github.com/crazybber
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* @Author: Edward
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* @Date: 2020-05-10 22:00:58
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* @Last Modified by: Edward
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* @Last Modified time: 2020-05-10 22:02:18
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*/
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import (
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"context"
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"errors"
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"sync"
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"time"
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)
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////////////////////////////////
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///使用HTTP请求的例子
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//每个搜索引擎时时刻刻都会遇到超大规模的请求的流量.
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//这里演示一个复杂一点的例子,同时使用Option 模式
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//ErrServiceUnavailable for error
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var (
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ErrTooManyRequests = errors.New("too many requests")
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@ -13,6 +27,29 @@ var (
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FailureThreshold = 10
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)
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//StateCheckerHandler check state
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type StateCheckerHandler func(counts counters) bool
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//StateChangedEventHandler set event handle
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type StateChangedEventHandler func(name string, from State, to State)
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//Option set Options
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type Option func(opts *Options)
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//RequestBreaker for protection
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type RequestBreaker struct {
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options Options
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mutex sync.Mutex
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state State
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generation uint64
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counts Counter
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}
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//NewRequestBreaker return a breaker
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func NewRequestBreaker() *RequestBreaker {
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}
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//State of current switch
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type State int
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@ -1,9 +1,51 @@
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package circuit
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import (
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"fmt"
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"io/ioutil"
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"net/http"
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"testing"
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)
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var breaker *RequestBreaker
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func TestBasicBreaker(t *testing.T) {
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var st Options
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st.Name = "HTTP GET"
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st.ReadyToTrip = func(counts counters) bool {
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failureRatio := float64(counts.TotalFailures) / float64(counts.Requests)
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return counts.Requests >= 3 && failureRatio >= 0.6
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}
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breaker = NewRequestBreaker(st)
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body, err := Get("https://bing.com/robots.txt")
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if err != nil {
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t.Fatal(err)
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}
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fmt.Println(string(body))
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}
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// Get wraps http.Get in CircuitBreaker.
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func Get(url string) ([]byte, error) {
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body, err := breaker.Execute(func() (interface{}, error) {
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resp, err := http.Get(url)
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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return nil, err
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}
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return body, nil
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})
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if err != nil {
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return nil, err
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}
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return body.([]byte), nil
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}
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