Fail gracefully when service unavaillable

ChangeLog.md

@@ -4,6 +4,9 @@
 
 ## Version XX.XX.XX:
 
+### All:
+- Fixed a bug where deserialization of service stats throws a TypeError when the service is unavailable.
+
 ### Blob:
 - create_from_* and and append_blob_from_* methods will return response_properties which contains the etag and last modified time.
 

azure/storage/_deserialization.py

@@ -184,7 +184,8 @@ def _convert_xml_to_service_stats(response):
 
     geo_replication = GeoReplication()
     geo_replication.status = geo_replication_element.find('Status').text
-    geo_replication.last_sync_time = parser.parse(geo_replication_element.find('LastSyncTime').text)
+    last_sync_time = geo_replication_element.find('LastSyncTime').text
+    geo_replication.last_sync_time = parser.parse(last_sync_time) if last_sync_time else None
 
     service_stats = ServiceStats()
     service_stats.geo_replication = geo_replication

tests/test_service_stats.py

@@ -1,4 +1,4 @@
-#-------------------------------------------------------------------------
+# -------------------------------------------------------------------------
 # Copyright (c) Microsoft.  All rights reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-#--------------------------------------------------------------------------
+# --------------------------------------------------------------------------
 import unittest
 
 from azure.storage.blob import BlockBlobService
@@ -21,20 +21,37 @@
     StorageTestCase,
     record,
 )
+from azure.storage.retry import (
+    LinearRetry
+)
 
-#------------------------------------------------------------------------------
+SERVICE_UNAVAILABLE_RESP_BODY = '<?xml version="1.0" encoding="utf-8"?><StorageServiceStats><GeoReplication><Status' \
+                              '>unavailable</Status><LastSyncTime></LastSyncTime></GeoReplication' \
+                              '></StorageServiceStats> '
 
-class ServiceStatsTest(StorageTestCase):
 
-    #--Helpers-----------------------------------------------------------------
+# --Test Class -----------------------------------------------------------------
+class ServiceStatsTest(StorageTestCase):
+    # --Helpers-----------------------------------------------------------------
     def _assert_stats_default(self, stats):
         self.assertIsNotNone(stats)
         self.assertIsNotNone(stats.geo_replication)
 
         self.assertEqual(stats.geo_replication.status, 'live')
         self.assertIsNotNone(stats.geo_replication.last_sync_time)
 
-    #--Test cases per service ---------------------------------------
+    def _assert_stats_unavailable(self, stats):
+        self.assertIsNotNone(stats)
+        self.assertIsNotNone(stats.geo_replication)
+
+        self.assertEqual(stats.geo_replication.status, 'unavailable')
+        self.assertIsNone(stats.geo_replication.last_sync_time)
+
+    @staticmethod
+    def override_response_body_with_unavailable_status(response):
+        response.body = SERVICE_UNAVAILABLE_RESP_BODY
+
+    # --Test cases per service ---------------------------------------
 
     @record
     def test_blob_service_stats(self):
@@ -47,6 +64,19 @@ def test_blob_service_stats(self):
         # Assert
         self._assert_stats_default(stats)
 
+    @record
+    def test_blob_service_stats_when_unavailable(self):
+        # Arrange
+        bs = self._create_storage_service(BlockBlobService, self.settings)
+        bs.response_callback = self.override_response_body_with_unavailable_status
+        bs.retry = LinearRetry(backoff=1).retry
+
+        # Act
+        stats = bs.get_blob_service_stats()
+
+        # Assert
+        self._assert_stats_unavailable(stats)
+
     @record
     def test_queue_service_stats(self):
         # Arrange
@@ -58,6 +88,19 @@ def test_queue_service_stats(self):
         # Assert
         self._assert_stats_default(stats)
 
+    @record
+    def test_queue_service_stats_when_unavailable(self):
+        # Arrange
+        qs = self._create_storage_service(QueueService, self.settings)
+        qs.response_callback = self.override_response_body_with_unavailable_status
+        qs.retry = LinearRetry(backoff=1).retry
+
+        # Act
+        stats = qs.get_queue_service_stats()
+
+        # Assert
+        self._assert_stats_unavailable(stats)
+
     @record
     def test_table_service_stats(self):
         # Arrange
@@ -69,6 +112,19 @@ def test_table_service_stats(self):
         # Assert
         self._assert_stats_default(stats)
 
-#------------------------------------------------------------------------------
+    @record
+    def test_table_service_stats_when_unavailable(self):
+        # Arrange
+        ts = self._create_storage_service(TableService, self.settings)
+        ts.response_callback = self.override_response_body_with_unavailable_status
+        ts.retry = LinearRetry(backoff=1).retry
+
+        # Act
+        stats = ts.get_table_service_stats()
+
+        # Assert
+        self._assert_stats_unavailable(stats)
+
+# ------------------------------------------------------------------------------
 if __name__ == '__main__':
     unittest.main()