How to read body from response with status 101 Switching Protocols

Question

I am connected to a server, in Kubernetes cluster, with POST request and headers to upgrade the request. I am using the following function:

func PostRequest(client *http.Client, url string, bodyData []byte) (*http.Response, error){
    req, _ := http.NewRequest("POST", url, bytes.NewBuffer(bodyData))
    //req.Header.Set("Authorization", "Bearer " + BEARER_TOKEN)
    req.Header.Set("X-Stream-Protocol-Version", "v2.channel.k8s.io")
    req.Header.Set("X-Stream-Protocol-Version", "channel.k8s.io")
    req.Header.Set("Upgrade", "SPDY/3.1")
    req.Header.Set("Connection","upgrade")
    req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

    resp, err := (*client).Do(req)

    return resp, err
}

After I received the response, I tried to read it but it stuck when I read the body:

url2 := "https://<serveri_ip>:10250/exec/default/mypod/mycontainer?command=ls&command=/&input=1&output=1&tty=1"

resp, err := PostRequest(api.GlobalClient, url2, []byte(""))
fmt.Println(r.Status)
fmt.Println(r.Header)
bodyBytes, err := ioutil.ReadAll(r.Body) // -> it stuck here
fmt.Println(string(bodyBytes))  

I suppose it tried to open websocket, so I tried to use gorilla websocket library like that:

u := url.URL{Scheme: "ws", Host: "<node_ip>:10250", Path: "/exec/default/mypod/mycontainer?command=ls&command=/&input=1&output=1&tty=1"}

interrupt := make(chan os.Signal, 1)
signal.Notify(interrupt, os.Interrupt)

c, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
if err != nil {
  log.Fatal("dial:", err)
}
defer c.Close()

But it printed an error:

2020/04/04 20:51:25 dial:websocket: bad handshake

What I am doing wrong?
How can I read response body from status "Switching Protocols"

Answer 1

I managed to do it with Kubernetes go-client library:

package main

import (
    "crypto/tls"
    "fmt"
    "net/http"
    "net/url"
    "os"
    "time"

    restclient "k8s.io/client-go/rest"
    "k8s.io/client-go/tools/remotecommand"
)


func main(){

    /*req.Header.Add("X-Stream-Protocol-Version", "v4.channel.k8s.io")
    req.Header.Add("X-Stream-Protocol-Version", "v3.channel.k8s.io")
    req.Header.Add("X-Stream-Protocol-Version", "v2.channel.k8s.io")
    req.Header.Add("X-Stream-Protocol-Version", "channel.k8s.io")
    req.Header.Add("Connection", "upgrade")
    req.Header.Add("Upgrade", "SPDY/3.1")*/
    //url2 := "https://123.123.123.123:10250/exec/default/my-pod/nginx?command=ls&command=/&input=1&output=1&tty=1"
    tr := &http.Transport{
        MaxIdleConns:       10,
        IdleConnTimeout:    30 * time.Second,
        DisableCompression: true,
        TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
    }

    config := &restclient.Config{
        Host:                "https://123.123.123.123:10250",
        APIPath:             "/exec/default/my-pod/nginx",
        TLSClientConfig:     restclient.TLSClientConfig{
            Insecure: true,
        },
        Transport:           tr,
    }

    url3 := &url.URL{
        Scheme:     "https",
        Opaque:     "",
        User:       nil,
        Host:       "123.123.123.123:10250",
        Path:       "/exec/default/my-pod/nginx",
        RawPath:    "",
        RawQuery:   "command=ls&command=/&input=1&output=1&tty=1",
    }
    exec, err := remotecommand.NewSPDYExecutor(config, "POST", url3)
    if err != nil {
        fmt.Println(err)
    }

    // Thanks for this blog post https://www.henryxieblogs.com/2019/05/
    err = exec.Stream(remotecommand.StreamOptions{
        Stdin:  os.Stdin,
        Stdout: os.Stdout,
        Stderr: os.Stderr,
        Tty:true,
    })

    fmt.Println(err)
}