On Azure .exists blob timeout, log the exception and return False

We have been experimenting some issues with Azure Blob storage. Our current
timeout is the django-storages default (20 secs). We want to reduce it to ~2s,
but without breaking the code and start returning 500. So, we log the error and
return False.

Author: humitos

readthedocs/storage/azure_storage.py

@@ -3,6 +3,7 @@
 
 """Django storage classes to use with Azure Blob storage service."""
 
+import logging
 from azure.common import AzureMissingResourceHttpError
 from django.conf import settings
 from django.contrib.staticfiles.storage import ManifestFilesMixin
@@ -13,6 +14,9 @@
 from .mixins import OverrideHostnameMixin
 
 
+log = logging.getLogger(__name__)
+
+
 class AzureBuildMediaStorage(BuildMediaStorageMixin, OverrideHostnameMixin, AzureStorage):
 
     """An Azure Storage backend for build artifacts."""
@@ -30,6 +34,14 @@ def url(self, name, expire=None, http_method=None):  # noqa
         """
         return super().url(name, expire)
 
+    def exists(self, name, timeout=None):
+        """Override to catch timeout exception and return False."""
+        try:
+            return super().exists(name)
+        except:
+            log.exception('Timeout calling Azure .exists. name=%s', name)
+            return False
+
 
 class AzureBuildStorage(AzureStorage):