net/http: fix docs on Transport connection reuse specifics

[liaojianqi]

What version of Go are you using (go version)?

go version go1.7 darwin/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

What did you do?

package main

import (
	"time"
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    resp, err := http.Get("http://127.0.0.1:8588")
    
    if err != nil {
        panic(err)
    }
    _, err = ioutil.ReadAll(resp.Body)
    if err != nil {
        panic(err)
    }

    resp2, err := http.Get("http://127.0.0.1:8588")
    
    if err != nil {
        panic(err)
    }
    _, err = ioutil.ReadAll(resp2.Body)
    if err != nil {
        panic(err)
    }

    fmt.Println("before time sleep")
    time.Sleep(time.Second * 35)
}

in GO net/http Response Body annotation says:

It is the caller's responsibility to close Body. The default HTTP client's Transport does not attempt to reuse HTTP/1.0 or HTTP/1.1 TCP connections ("keep-alive") unless the Body is read to completion and is closed.

yeah, it say we must read body complete AND close body.
in the above code, after read resp.Body I don't close the resp.Body. so, the http client should't reuse the tcp connection. so there will be two tcp connection handshark in wireshark, but I only see ONE.
so, maybe the net/http's comment has something wrong?
thank you.

[davecheney]

What answer would you like to see? Do you want to control the number of outgoing connections?

…

On 1 Dec 2017, at 16:53, LoinLiao ***@***.***> wrote: Please answer these questions before submitting your issue. Thanks! What version of Go are you using (go version)? go version go1.7 darwin/amd64 Does this issue reproduce with the latest release? yes What operating system and processor architecture are you using (go env)? What did you do? package main import ( "time" "fmt" "io/ioutil" "net/http" ) func main() { resp, err := http.Get("http://127.0.0.1:8588") if err != nil { panic(err) } _, err = ioutil.ReadAll(resp.Body) if err != nil { panic(err) } resp2, err := http.Get("http://127.0.0.1:8588") if err != nil { panic(err) } _, err = ioutil.ReadAll(resp2.Body) if err != nil { panic(err) } fmt.Println("before time sleep") time.Sleep(time.Second * 35) } in GO net/http Response Body annotation says: It is the caller's responsibility to close Body. The default HTTP client's Transport does not attempt to reuse HTTP/1.0 or HTTP/1.1 TCP connections ("keep-alive") unless the Body is read to completion and is closed. yeah, it say we must read body complete AND close body. in the above code, after read resp.Body I don't close the resp.Body. so, the http client should't reuse the tcp connection. so there will be two tcp connection handshark in wireshark, but I only see ONE. so, maybe the net/http's comment has something wrong? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[liaojianqi]

What makes me wonder is resp2 should not reuse tcp connection because I don't call resp.Body.Close(). so I will see TWO tcp handshake. but I only see ONE. so resp reuse tcp connection created by resp, but i don't call resp.Body.Close().
and in net/http response says:

The default HTTP client's Transport does not attempt to reuse HTTP/1.0 or HTTP/1.1 TCP connections ("keep-alive") unless the Body is read to completion and is closed.

[bradfitz]

I'll update it to something slightly vaguer and less promise-sounding.

The reality is that it'll do it if it can.

[gopherbot]

Change https://golang.org/cl/86276 mentions this issue: net/http: soften wording around when the Transport reuses connections