Go 客户端程序生成大量 TIME

本文介绍了Go 客户端程序生成大量 TIME_WAIT 状态的套接字的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个 Go 程序，它从多个 goroutine 生成大量 HTTP 请求.运行一会，程序吐出一个错误:connect:cannotassignrequested address.

I have a Go program that generates a lot of HTTP requests from multiple goroutines. after running for a while, the program spits out an error: connect: cannot assign requested address.

在使用 netstat 进行检查时，我在 TIME_WAIT 中获得大量连接 (28229).

When checking with netstat, I get a high number (28229) of connections in TIME_WAIT.

TIME_WAIT 套接字的大量发生在 goroutine 的数量为 3 时发生，并且严重到足以导致崩溃时为 5.

The high number of TIME_WAIT sockets happens when I the number of goroutines is 3 and is severe enough to cause a crash when it is 5.

我在 docker 下运行 Ubuntu 14.4 并使用 1.7 版

I run Ubuntu 14.4 under docker and go version 1.7

这是 Go 程序.

package main import ( "io/ioutil" "log" "net/http" "sync" ) var wg sync.WaitGroup var url="172.17.0.9:3000/"; const num_coroutines=5; const num_request_per_coroutine=100000 func get_page(){ response, err := http.Get(url) if err != nil { log.Fatal(err) } else { defer response.Body.Close() _, err =ioutil.ReadAll(response.Body) if err != nil { log.Fatal(err) } } } func get_pages(){ defer wg.Done() for i := 0; i < num_request_per_coroutine; i++{ get_page(); } } func main() { for i:=0;i<num_coroutines;i++{ wg.Add(1) go get_pages() } wg.Wait() }

这是服务器程序:

package main import ( "fmt" "net/http" "log" ) var count int; func sayhelloName(w http.ResponseWriter, r *http.Request) { count++; fmt.Fprintf(w,"Hello World, count is %d",count) // send data to client side } func main() { http.HandleFunc("/", sayhelloName) // set router err := http.ListenAndServe(":3000", nil) // set listen port if err != nil { log.Fatal("ListenAndServe: ", err) } }

推荐答案

默认的 http.Transport 打开和关闭连接的速度太快.由于所有连接都指向相同的主机:端口组合，您需要增加 MaxIdleConnsPerHost 以匹配您的 num_coroutines 值.否则，传输将经常关闭额外的连接，然后立即重新打开它们.

The default http.Transport is opening and closing connections too quickly. Since all connections are to the same host:port combination, you need to increase MaxIdleConnsPerHost to match your value for num_coroutines. Otherwise, the transport will frequently close the extra connections, only to have them reopened immediately.

您可以在默认传输上全局设置:

You can set this globally on the default transport:

http.DefaultTransport.(*http.Transport).MaxIdleConnsPerHost = numCoroutines

或者在创建自己的传输时

Or when creating your own transport

t := &http.Transport{ Proxy: http.ProxyFromEnvironment, DialContext: (&net.Dialer{ Timeout: 30 * time.Second, KeepAlive: 30 * time.Second, }).DialContext, MaxIdleConnsPerHost: numCoroutines, MaxIdleConns: 100, IdleConnTimeout: 90 * time.Second, TLSHandshakeTimeout: 10 * time.Second, ExpectContinueTimeout: 1 * time.Second, }

类似问题:转到 http.Get、并发和对等方重置连接"