Get cookie from Golang post

//Create Client

client=http.client{}

//Create Varible

var cookie []*http.Cookie

// Create Request

req, _ := http.NewRequest("GET", url, nil)
resp, err := client.Do(req) //send request
if err != nil {
return 
}
cookie = resp.Cookies() //save cookies

// Create New Request

req, _ := http.NewRequest("POST", url, nil)   
for i := range cookie {
    req.AddCookie(cookie[i])
}
resp, err := client.Do(req) //send request
if err != nil {
      return 
              }

To get the cookies you should call the Cookies() method that's part of http.Response, try this:

for _, cookie := range resp.Cookies() {
  fmt.Println("Found a cookie named:", cookie.Name)
}

See the Cookie fields here.