Go语言 如果实现http重连？
怎样做到每次使用一个连接发送和接收前就设置超时呢？我想了个办法是在Dial回调返回自己包装过的TimeoutConn，间接的调用真实的Conn，这样就可以再每次Read和Write之前设置超时时间了。
以下是修改后的实验代码：
//
// How to set timeout for http.Get() in golang
//
package main
import (
"io"
"io/ioutil"
"log"
"net"
"net/http"
"sync"
"time"
)
type TimeoutConn struct {
conn net.Conn
timeout time.Duration
}
func NewTimeoutConn(conn net.Conn, timeout time.Duration) *TimeoutConn {
return &TimeoutConn{
conn: conn,
timeout: timeout,
}
}
func (c *TimeoutConn) Read(b []byte) (n int, err error) {
c.SetReadDeadline(time.Now().Add(c.timeout))
return c.conn.Read(b)
}
func (c *TimeoutConn) Write(b []byte) (n int, err error) {
c.SetWriteDeadline(time.Now().Add(c.timeout))
return c.conn.Write(b)
}
func (c *TimeoutConn) Close() error {
return c.conn.Close()
}
func (c *TimeoutConn) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *TimeoutConn) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
func (c *TimeoutConn) SetDeadline(t time.Time) error {
return c.conn.SetDeadline(t)
}
func (c *TimeoutConn) SetReadDeadline(t time.Time) error {
return c.conn.SetReadDeadline(t)
}
func (c *TimeoutConn) SetWriteDeadline(t time.Time) error {
return c.conn.SetWriteDeadline(t)
}
func main() {
client := &http.Client{
Transport: &http.Transport{
Dial: func(netw, addr string) (net.Conn, error) {
log.Printf("dial to %s://%s", netw, addr)
conn, err := net.DialTimeout(netw, addr, time.Second*2)
if err != nil {
return nil, err
}
return NewTimeoutConn(conn, time.Second*2), nil
},
ResponseHeaderTimeout: time.Second * 2,
},
}
addr := StartTestServer()
SendTestRequest(client, "1st", addr, "normal")
SendTestRequest(client, "2st", addr, "normal")
SendTestRequest(client, "3st", addr, "timeout")
SendTestRequest(client, "4st", addr, "normal")
time.Sleep(time.Second * 3)
SendTestRequest(client, "5st", addr, "normal")
}
func StartTestServer() string {
listener, err := net.Listen("tcp", ":0")
if err != nil {
log.Fatalf("failed to listen - %s", err.Error())
}
wg := new(sync.WaitGroup)
wg.Add(1)
go func() {
http.HandleFunc("/normal", func(w http.ResponseWriter, req *http.Request) {
time.Sleep(1000 * time.Millisecond)
io.WriteString(w, "ok")
})
http.HandleFunc("/timeout", func(w http.ResponseWriter, req *http.Request) {
time.Sleep(2500 * time.Millisecond)
io.WriteString(w, "ok")
})
wg.Done()
err = http.Serve(listener, nil)
if err != nil {
log.Fatalf("failed to start HTTP server - %s", err.Error())
}
}()
wg.Wait()
log.Printf("start http server at http://%s/", listener.Addr())
return listener.Addr().String()
}
func SendTestRequest(client *http.Client, id, addr, path string) {
req, err := http.NewRequest("GET", "http://"+addr+"/"+path, nil)
if err != nil {
log.Fatalf("new request failed - %s", err)
}
req.Header.Add("Connection", "keep-alive")
switch path {
case "normal":
if resp, err := client.Do(req); err != nil {
log.Fatalf("%s request failed - %s", id, err)
} else {
result, err2 := ioutil.ReadAll(resp.Body)
if err2 != nil {
log.Fatalf("%s response read failed - %s", id, err2)
}
resp.Body.Close()
log.Printf("%s request - %s", id, result)
}
case "timeout":
if _, err := client.Do(req); err == nil {
log.Fatalf("%s request not timeout", id)
} else {
log.Printf("%s request - %s", id, err)
}
}
}本文参与 腾讯云自媒体分享计划，分享自微信公众号。
原始发表：2016-01-08，如有侵权请联系 cloudcommunity@tencent.com 删除
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