屏蔽网页 的网站备案,佛山网站建设怎么选,湖南又出现5例,wordpress转app记录一次Go HTTP Client TIME_WAIT的优化 业务流程 分析
通过容器监控发现服务到事件总线的负载均衡之间有大量的短链接#xff0c;回看一下代码
发送请求的代码
func SendToKEvent(ev *KEvent) error {data, err : json.Marshal(ev.Data)if err ! nil {return err}log.Pri… 记录一次Go HTTP Client TIME_WAIT的优化 业务流程 分析
通过容器监控发现服务到事件总线的负载均衡之间有大量的短链接回看一下代码
发送请求的代码
func SendToKEvent(ev *KEvent) error {data, err : json.Marshal(ev.Data)if err ! nil {return err}log.Println(string(data))if !sendEvent {log.Println(------ SEND_EVENT IS DISABLED ------)return nil}defer util.TimeCost(SendToKEvent)()body : bytes.NewReader(data)ctx, cancel : context.WithTimeout(context.Background(), 2*time.Second)defer cancel()req, err : http.NewRequest(http.MethodPost, ev.Url, body)if err ! nil {return err}req.WithContext(ctx)req.Header.Set(Content-Type, application/json; charsetutf-8)req.Header.Set(......, ......)for k, v : range ev.ExtMap {req.Header.Set(k, v)}resp, err : httpc.HttpClient.Do(req)if err ! nil {return err}defer resp.Body.Close()// 事件总线 2xx 均为正常if resp.StatusCode 300 || resp.StatusCode 200 {return fmt.Errorf(req failed, resp%v, resp)}return nil
}http client的代码
var (HttpClient http.Client{Transport: http.Transport{Proxy: http.ProxyFromEnvironment,DialContext: func(ctx context.Context, network, addr string) (conn net.Conn, e error) {return (net.Dialer{Timeout: 10 * time.Second,KeepAlive: 90 * time.Second,}).DialContext(ctx, network, addr)},ForceAttemptHTTP2: true,TLSHandshakeTimeout: 5 * time.Second,ResponseHeaderTimeout: 30 * time.Second,MaxIdleConnsPerHost: 10,IdleConnTimeout: 90 * time.Second,ExpectContinueTimeout: 1 * time.Second,},}
)
代码看起来没啥问题,但想到了之前处理过Golang ES client的一个问题
https://jiankunking.com/tcp-state-diagram.html
看下上文中TIME_WAIT部分发现还真是 https://pkg.go.dev/net/http#Response
// The http Client and Transport guarantee that Body is always
// non-nil, even on responses without a body or responses with
// a zero-length body. It is the callers responsibility to
// close Body. The default HTTP clients Transport may not
// reuse HTTP/1.x keep-alive TCP connections if the Body is
// not read to completion and closed.调整代码
func SendToKEvent(ev *KEvent) error {......resp, err : httpc.HttpClient.Do(req)if err ! nil {return err}defer resp.Body.Close()io.Copy(ioutil.Discard, resp.Body) // -- 添加这一行......return nil
}重新部署后,发现TIME_WAIT的链接少了很多但还是有10几个
bash-5.0# netstat -anp |grep TIME
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:10964 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:45738 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:21178 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:37354 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:10966 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:37352 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:61524 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:61526 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:21180 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:33256 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:45736 TIME_WAIT -
tcp 0 0 ::ffff:172.16.3.247:8080 ::ffff:10.200.76.64:33254 TIME_WAIT -
bash-5.0#
这里需要注意一下
172.16.3.247是服务POD的ip10.200.76.64是POD所在宿主机的ip
也就是说POD跟宿主机之间有短链接,那这几个短链接是在做啥呢
抓包看下
着重看一下No 502这一行
Frame 502: 177 bytes on wire (1416 bits), 177 bytes captured (1416 bits)
Ethernet II, Src: ee:ee:ee:ee:ee:ee (ee:ee:ee:ee:ee:ee), Dst: b6:cd:6a:f8:69:5e (b6:cd:6a:f8:69:5e)
Internet Protocol Version 4, Src: 10.200.76.64, Dst: 172.16.3.247
Transmission Control Protocol, Src Port: 29978, Dst Port: 8080, Seq: 1, Ack: 1, Len: 111
Hypertext Transfer ProtocolGET /healthz HTTP/1.1\r\n -- 注意这一行,这个接口是服务配置的存活检查接口Host: 172.16.3.247:8080\r\nUser-Agent: kube-probe/1.21\r\nAccept: */*\r\nConnection: close\r\n -- 注意这一行\r\n[Response in frame: 506][Full request URI: http://172.16.3.247:8080/healthz]Connection
Connection: keep-alive 当一个网页打开完成后客户端和服务器之间用于传输HTTP数据的TCP连接不会关闭如果客户端再次访问这个服务器上的网页会继续使用这一条已经建立的连接Connection: close 代表一个Request完成后客户端和服务器之间用于传输HTTP数据的TCP连接会关闭 当客户端再次发送Request需要重新建立TCP连接。
从Connection的注释可以看出当请求header中带有Connection: keep-alive表明该请求是会是一个短链接。
看下服务的Deployment的配置 livenessProbe:failureThreshold: 3httpGet:path: /healthzport: 8080scheme: HTTPperiodSeconds: 10successThreshold: 1timeoutSeconds: 1到这里问题都可以解释的通了,Kubernetes会每10秒请求一次服务的存活检查的接口,每一次都是短链接,而TIME_WAIT的默认值是120s。
那服务TIME_WAIT的链接应该会一直保持在11-13个左右。
到这里所有的问题都就可以解释了。
结论
Go HTTP Client请求完了,即使业务不关注响应的Body,还是要在代码中read一下body。只要服务配置了存活检查就会有短链接短链接的数据取决于检查间隔时间的配置。
