fix: an Aborted exception isn't properly retried (#345)

Author: Ilya Gurov

google/cloud/spanner_dbapi/cursor.py

@@ -206,7 +206,12 @@ def execute(self, sql, args=None):
                 (self._result_set, self._checksum,) = self.connection.run_statement(
                     statement
                 )
-                self._itr = PeekIterator(self._result_set)
+                while True:
+                    try:
+                        self._itr = PeekIterator(self._result_set)
+                        break
+                    except Aborted:
+                        self.connection.retry_transaction()
                 return
 
             if classification == parse_utils.STMT_NON_UPDATING:
@@ -352,7 +357,12 @@ def _handle_DQL(self, sql, params):
                 self._result_set = res
                 # Read the first element so that the StreamedResultSet can
                 # return the metadata after a DQL statement. See issue #155.
-                self._itr = PeekIterator(self._result_set)
+                while True:
+                    try:
+                        self._itr = PeekIterator(self._result_set)
+                        break
+                    except Aborted:
+                        self.connection.retry_transaction()
                 # Unfortunately, Spanner doesn't seem to send back
                 # information about the number of rows available.
                 self._row_count = _UNSET_COUNT

tests/unit/spanner_dbapi/test_cursor.py

@@ -549,6 +549,74 @@ def test_get_table_column_schema(self):
             )
             self.assertEqual(result, expected)
 
+    def test_peek_iterator_aborted(self):
+        """
+        Checking that an Aborted exception is retried in case it happened
+        while streaming the first element with a PeekIterator.
+        """
+        from google.api_core.exceptions import Aborted
+        from google.cloud.spanner_dbapi.connection import connect
+
+        with mock.patch(
+            "google.cloud.spanner_v1.instance.Instance.exists", return_value=True,
+        ):
+            with mock.patch(
+                "google.cloud.spanner_v1.database.Database.exists", return_value=True,
+            ):
+                connection = connect("test-instance", "test-database")
+
+        cursor = connection.cursor()
+        with mock.patch(
+            "google.cloud.spanner_dbapi.utils.PeekIterator.__init__",
+            side_effect=(Aborted("Aborted"), None),
+        ):
+            with mock.patch(
+                "google.cloud.spanner_dbapi.connection.Connection.retry_transaction"
+            ) as retry_mock:
+                with mock.patch(
+                    "google.cloud.spanner_dbapi.connection.Connection.run_statement",
+                    return_value=((1, 2, 3), None),
+                ):
+                    cursor.execute("SELECT * FROM table_name")
+
+                retry_mock.assert_called_with()
+
+    def test_peek_iterator_aborted_autocommit(self):
+        """
+        Checking that an Aborted exception is retried in case it happened while
+        streaming the first element with a PeekIterator in autocommit mode.
+        """
+        from google.api_core.exceptions import Aborted
+        from google.cloud.spanner_dbapi.connection import connect
+
+        with mock.patch(
+            "google.cloud.spanner_v1.instance.Instance.exists", return_value=True,
+        ):
+            with mock.patch(
+                "google.cloud.spanner_v1.database.Database.exists", return_value=True,
+            ):
+                connection = connect("test-instance", "test-database")
+
+        connection.autocommit = True
+        cursor = connection.cursor()
+        with mock.patch(
+            "google.cloud.spanner_dbapi.utils.PeekIterator.__init__",
+            side_effect=(Aborted("Aborted"), None),
+        ):
+            with mock.patch(
+                "google.cloud.spanner_dbapi.connection.Connection.retry_transaction"
+            ) as retry_mock:
+                with mock.patch(
+                    "google.cloud.spanner_dbapi.connection.Connection.run_statement",
+                    return_value=((1, 2, 3), None),
+                ):
+                    with mock.patch(
+                        "google.cloud.spanner_v1.database.Database.snapshot"
+                    ):
+                        cursor.execute("SELECT * FROM table_name")
+
+                retry_mock.assert_called_with()
+
     def test_fetchone_retry_aborted(self):
         """Check that aborted fetch re-executing transaction."""
         from google.api_core.exceptions import Aborted