What HTTP response codes are retried by python Requests

Question

What are the list of HTTP response status codes are retried by default and how many times by the Python Requests. How can I change the number of retries? I couldn't find any documentation for it.

I tried below code and I saw there were two retries done on 401 status code.

import requests
from http.client import HTTPConnection
from requests.auth import HTTPDigestAuth

HTTPConnection.debuglevel = 1
requests.adapters.DEFAULT_RETRIES = 5

def test():
    data = 'testdata'
    username = 'testuser'
    password = 'test'
    url='https://example.com:443/captionen_0001.vtt'
    try:
        response = requests.put(url, auth=HTTPDigestAuth(username,password), data=data, verify=False)
    except Exception as e:
        print('error'+str(e))

test()

  warnings.warn(
send: b'PUT /channel_captionen_0001.vtt HTTP/1.1\r\nHost: example.com\r\nUser-Agent: python-requests/2.24.0\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nConnection: keep-alive\r\nContent-Length: 8\r\n\r\n'
send: b'testdata'
reply: 'HTTP/1.1 401 Authorization Required\r\n'
header: Date: Sat, 05 Feb 2022 07:50:25 GMT
  
  warnings.warn(
send: b'PUT /channel_captionen_0001.vtt HTTP/1.1\r\nHost: example.com\r\nUser-Agent: python-requests/2.24.0\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nConnection: keep-alive\r\nContent-Length: 8\r\nAuthorization: Digest username="testuser", realm="WebDAV", nonce="tE/JnkDXBQA=7fb88e30d6a6d59095534a2a6db3bbbe85845db3", uri="/channel_captionen_0001.vtt", response="1c3299c716797e8f36528f6e6dbaeb50", algorithm="MD5", qop="auth", nc=00000001, cnonce="dd0835ef485c6b71"\r\n\r\n'
send: b'testdata'
reply: 'HTTP/1.1 401 Authorization Required\r\n'
header: Date: Sat, 05 Feb 2022 07:50:25 GMT

Answer 1

It's not obviously to find. You have to know requests is not the package that manage the connection, urllib3 does.

In the source code of HTTPAdapter (use it when you want more control on requests ), the docstring on max_retries parameter said:

If you need granular control over the conditions under which we retry a request, import urllib3's Retry class and pass that instead

Now you can refer to the documentation of urllib3 for Retry class.

Read especially status_forcelist parameter and RETRY_AFTER_STATUS_CODES (default: frozenset({413, 429, 503}) )

Update

import requests
import urllib3

my_code_list = [401, 403, ...]

s = requests.Session()
r = urllib3.util.Retry(status_forcelist=my_code_list)
a = requests.adapters.HTTPAdapter(max_retries=r)
s.mount('http://', a)