ISSUE-925: Handle rate limit error

* enable retries of 5xx status codes
* add status code 429 to the list of retriable errors
* remove status code 401 from the list of retriable errors by resilientsession

FIXES #925

jira/resilientsession.py

@@ -88,7 +88,7 @@ def raise_on_error(r: Optional[Response], verb="???", **kwargs):
 class ResilientSession(Session):
     """This class is supposed to retry requests that do return temporary errors.
 
-    At this moment it supports: 502, 503, 504
+    At this moment it supports: 429, 502, 503, 504
     """
 
     def __init__(self, timeout=None):
@@ -113,11 +113,10 @@ def __recoverable(
                 f"Got ConnectionError [{response}] errno:{response.errno} on {request} {url}\n{vars(response)}\n{response.__dict__}"
             )
         if isinstance(response, Response):
-            if response.status_code in [502, 503, 504, 401]:
-                # 401 UNAUTHORIZED still randomly returned by Atlassian Cloud as of 2017-01-16
+            if response.status_code in [429, 502, 503, 504]:
+                # 401 UNAUTHORIZED still randomly returned by Atlassian Cloud as of 2017-01-16 and are handled by jira.JiraCookieAuth.handle_401
                 msg = f"{response.status_code} {response.reason}"
-                # 2019-07-25: Disabled recovery for codes above^
-                return False
+                return True
             elif not (
                 response.status_code == 200
                 and len(response.content) == 0

tests/test_resilientsession.py

@@ -1,6 +1,11 @@
 import logging
+from unittest.mock import Mock, patch
+
+import pytest
+from requests import Response
 
 import jira.resilientsession
+from jira.exceptions import JIRAError
 from tests.conftest import JiraTestCase
 
 
@@ -53,3 +58,16 @@ def test_logging_with_connection_error(self):
     def tearDown(self):
         jira.resilientsession.logging.getLogger().removeHandler(self.loggingHandler)
         del self.loggingHandler
+
+
+@patch("requests.Session.get")
+def test_throttling_error_is_retried(mocked_method: Mock):
+    mocked_throttled_response: Response = Response()
+    mocked_throttled_response.status_code = 429
+    mocked_method.return_value = mocked_throttled_response
+    session: jira.resilientsession.ResilientSession = (
+        jira.resilientsession.ResilientSession()
+    )
+    with pytest.raises(JIRAError):
+        session.get("mocked_url")
+    assert mocked_method.call_count == 4