[TOC] ## 概述 ## 案例 ### http ``` package main import ( "errors" "fmt" "log" "net/http" "os" "github.com/afex/hystrix-go/hystrix" ) const commandName = "producer_api" func main() { hystrix.ConfigureCommand(commandName, hystrix.CommandConfig{ Timeout: 500, MaxConcurrentRequests: 9, ErrorPercentThreshold: 50, RequestVolumeThreshold: 3, SleepWindow: 1000, }) http.HandleFunc("/", logger(handle)) log.Println("listening on :8080") http.ListenAndServe(":8080", nil) } func handle(w http.ResponseWriter, r *http.Request) { output := make(chan bool, 1) errors := hystrix.Go(commandName, func() error { // 像其他服務請求 err := callChargeProducerAPI() // 重試 //err := callWithRetryV1() if err == nil { output <- true } return err }, nil) select { case out := <-output: // success log.Printf("success %v", out) case err := <-errors: // failure log.Printf("failed %s", err) } } // logger is Handler wrapper function for logging func logger(fn http.HandlerFunc) http.HandlerFunc { return func(w http.ResponseWriter, r *http.Request) { log.Println(r.URL.Path, r.Method) fn(w, r) } } func callChargeProducerAPI() error { fmt.Println(os.Getenv("SERVER_ERROR")) // 設置為 server_error 則表示請求失敗 if os.Getenv("SERVER_ERROR") == "1" { return errors.New("503 error") } return nil } func callWithRetryV1() (err error) { for index := 0; index < 3; index++ { // call producer API err := callChargeProducerAPI() if err != nil { return err } } return }