Is resp.Body.Close() required if I don't need response?

Question

I'm making request which I don't need response from. Would it cause any problems if I do it like this?

client = &http.Client{
    Timeout: time.Duration(15 * time.Second),
}
...
...
_, err := client.Do(req)

Answer 1

Quoting from the doc of Client.Do()

If the returned error is nil, the Response will contain a non-nil Body which the user is expected to close. If the Body is not both read to EOF and closed, the Client's underlying RoundTripper (typically Transport) may not be able to re-use a persistent TCP connection to the server for a subsequent "keep-alive" request.

So yes, you always have to close it if there is no error. You are also expected to read the body to EOF before closing. Quoting from http.Response:

// The default HTTP client's Transport may not
// reuse HTTP/1.x "keep-alive" TCP connections if the Body is
// not read to completion and closed.

If you don't need the body, you may discard it like this:

resp, err := client.Do(req)
if err != nil {
    // handle error and return
    return
}
defer resp.Close()
io.Copy(ioutil.Discard, resp.Body)

If there is an error, see related question: Do we need to close the response object if an error occurs while calling http.Get(url)?