Retry mechanism (#35)

* Beta version of retry mechanism

* added 502 response code and exponential backoff

* bugfix

* Update CHANGELOG.rst

* fixed tests

* flake8

* Update CHANGELOG.rst

CHANGELOG.rst

@@ -20,6 +20,18 @@ Possible types of changes are:
 Unreleased
 ----------
 
+1.4.0 - 12.06.2020
+------------------
+
+Changed
+'''''''
+- The underlying HTTP client is now configured to automatically retry requests that return a status code of "429 Too Many Requests", "502 Bad Gateway", "503 Service Unavailable" and "504 Gateway Timeout".
+
+Fixed
+'''''
+- Some tests were still calling ``get_bucket()`` from the constructor of ``GCSFS``.
+
+
 1.3.0 - 20.05.2020
 ------------------
 

fs_gcsfs/_gcsfs.py

@@ -19,6 +19,9 @@
 from fs.time import datetime_to_epoch
 from google.cloud.storage import Client
 from google.cloud.storage.blob import Blob
+from requests.adapters import HTTPAdapter
+from urllib3.util.retry import Retry
+
 
 __all__ = ["GCSFS"]
 
@@ -57,6 +60,7 @@ def __init__(self,
                  root_path: str = None,
                  create: bool = False,
                  client: Client = None,
+                 retry: int = 5,
                  strict: bool = True):
         super().__init__()
         self._bucket_name = bucket_name
@@ -71,6 +75,13 @@ def __init__(self,
         if self.client is None:
             self.client = Client()
 
+        if retry:
+            adapter = HTTPAdapter(max_retries=Retry(total=retry,
+                                                    status_forcelist=[429, 502, 503, 504],
+                                                    method_whitelist=False,  # retry on any HTTP method
+                                                    backoff_factor=0.5))
+            self.client._http.mount("https://", adapter)
+
         self.bucket = self.client.bucket(self._bucket_name)
 
         if self._prefix != "":

fs_gcsfs/tests/conftest.py

@@ -14,7 +14,7 @@ def client():
 
 @pytest.fixture(scope="module")
 def bucket(client):
-    return client.get_bucket(os.environ['TEST_BUCKET'])
+    return client.bucket(os.environ['TEST_BUCKET'])
 
 
 @pytest.fixture(scope="function")

fs_gcsfs/tests/test_gcsfs.py

@@ -1,6 +1,7 @@
 import os
 import unittest
 import uuid
+from unittest import mock
 
 import pytest
 from fs import open_fs
@@ -18,7 +19,7 @@ class TestGCSFS(FSTestCases, unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.client = Client()
-        cls.bucket = cls.client.get_bucket(TEST_BUCKET)
+        cls.bucket = cls.client.bucket(TEST_BUCKET)
         super().setUpClass()
 
     def setUp(self):
@@ -42,6 +43,10 @@ class ClientMock:
         def bucket(self, _):
             pass
 
+        @property
+        def _http(self):
+            return mock.MagicMock()
+
     return ClientMock()