Improve retrying failed API server connections (#71)

When the API server got terminated in the middle of a connection (perhaps because of a new deployment), it didn't finish the response properly, and the connection errored out with a `"Connection broken: InvalidChunkLength(got length b'', 0 bytes read)"` error. This change extends the error-retrying logic to retry the request in case of those errors as well.

Author: fnesveda

CHANGELOG.md

@@ -1,6 +1,13 @@
 Changelog
 =========
 
+[0.5.0](../../releases/tag/v0.5.0) - 2021-09-16
+-----------------------------------------------
+
+### Changed
+
+- improved retrying broken API server connections
+
 [0.4.0](../../releases/tag/v0.4.0) - 2021-09-07
 -----------------------------------------------
 

src/apify_client/_errors.py

@@ -1,6 +1,7 @@
 from typing import Optional
 
 import requests
+from requests.exceptions import ChunkedEncodingError, ConnectionError, Timeout
 
 
 class ApifyClientError(Exception):
@@ -69,3 +70,15 @@ def __init__(self, response: requests.models.Response) -> None:
         self.name = 'InvalidResponseBodyError'
         self.code = 'invalid-response-body'
         self.response = response
+
+
+def _is_retryable_error(e: Exception) -> bool:
+    if isinstance(e, (InvalidResponseBodyError, ConnectionError, Timeout)):
+        return True
+
+    # This can happen if an API server pod restarts while handling a long-running request
+    if isinstance(e, ChunkedEncodingError):
+        if str(e).startswith('("Connection broken: InvalidChunkLength(got length b\'\', 0 bytes read)"'):
+            return True
+
+    return False

src/apify_client/_http_client.py

@@ -6,9 +6,8 @@
 from typing import Any, Callable, Dict, Optional
 
 import requests
-from requests.exceptions import ConnectionError, Timeout
 
-from ._errors import ApifyApiError, InvalidResponseBodyError
+from ._errors import ApifyApiError, InvalidResponseBodyError, _is_retryable_error
 from ._types import JSONSerializable
 from ._utils import _is_content_type_json, _is_content_type_text, _is_content_type_xml, _retry_with_exp_backoff
 from ._version import __version__
@@ -82,10 +81,11 @@ def _make_request(bail: Callable, attempt: int) -> requests.models.Response:  #
                     setattr(response, '_maybe_parsed_body', _maybe_parsed_body)
                     return response
 
-            except (ConnectionError, Timeout, InvalidResponseBodyError) as e:
-                raise e
             except Exception as e:
-                bail(e)
+                if _is_retryable_error(e):
+                    raise e
+                else:
+                    bail(e)
 
             api_error = ApifyApiError(response, attempt)
             if response.status_code == HTTPStatus.TOO_MANY_REQUESTS or response.status_code >= 500:

src/apify_client/_version.py

@@ -1 +1 @@
-__version__ = '0.4.0'
+__version__ = '0.5.0'