API Core: Retry.__init__ add on_error (#8892)

Author: emar-kar

google/api_core/retry.py

@@ -237,12 +237,14 @@ def __init__(
         maximum=_DEFAULT_MAXIMUM_DELAY,
         multiplier=_DEFAULT_DELAY_MULTIPLIER,
         deadline=_DEFAULT_DEADLINE,
+        on_error=None
     ):
         self._predicate = predicate
         self._initial = initial
         self._multiplier = multiplier
         self._maximum = maximum
         self._deadline = deadline
+        self._on_error = on_error
 
     def __call__(self, func, on_error=None):
         """Wrap a callable with retry behavior.
@@ -257,6 +259,8 @@ def __call__(self, func, on_error=None):
             Callable: A callable that will invoke ``func`` with retry
                 behavior.
         """
+        if self._on_error is not None:
+            on_error = self._on_error
 
         @general_helpers.wraps(func)
         def retry_wrapped_func(*args, **kwargs):
@@ -290,6 +294,7 @@ def with_deadline(self, deadline):
             maximum=self._maximum,
             multiplier=self._multiplier,
             deadline=deadline,
+            on_error=self._on_error,
         )
 
     def with_predicate(self, predicate):
@@ -308,6 +313,7 @@ def with_predicate(self, predicate):
             maximum=self._maximum,
             multiplier=self._multiplier,
             deadline=self._deadline,
+            on_error=self._on_error,
         )
 
     def with_delay(self, initial=None, maximum=None, multiplier=None):
@@ -328,16 +334,18 @@ def with_delay(self, initial=None, maximum=None, multiplier=None):
             maximum=maximum if maximum is not None else self._maximum,
             multiplier=multiplier if maximum is not None else self._multiplier,
             deadline=self._deadline,
+            on_error=self._on_error,
         )
 
     def __str__(self):
         return (
             "<Retry predicate={}, initial={:.1f}, maximum={:.1f}, "
-            "multiplier={:.1f}, deadline={:.1f}>".format(
+            "multiplier={:.1f}, deadline={:.1f}, on_error={}>".format(
                 self._predicate,
                 self._initial,
                 self._maximum,
                 self._multiplier,
                 self._deadline,
+                self._on_error,
             )
         )

tests/unit/test_retry.py

@@ -161,20 +161,25 @@ def test_constructor_defaults(self):
         assert retry_._maximum == 60
         assert retry_._multiplier == 2
         assert retry_._deadline == 120
+        assert retry_._on_error is None
 
     def test_constructor_options(self):
+        _some_function = mock.Mock()
+
         retry_ = retry.Retry(
             predicate=mock.sentinel.predicate,
             initial=1,
             maximum=2,
             multiplier=3,
             deadline=4,
+            on_error=_some_function,
         )
         assert retry_._predicate == mock.sentinel.predicate
         assert retry_._initial == 1
         assert retry_._maximum == 2
         assert retry_._multiplier == 3
         assert retry_._deadline == 4
+        assert retry_._on_error is _some_function
 
     def test_with_deadline(self):
         retry_ = retry.Retry()
@@ -209,7 +214,8 @@ def test___str__(self):
         assert re.match(
             (
                 r"<Retry predicate=<function.*?if_exception_type.*?>, "
-                r"initial=1.0, maximum=60.0, multiplier=2.0, deadline=120.0>"
+                r"initial=1.0, maximum=60.0, multiplier=2.0, deadline=120.0, "
+                r"on_error=None>"
             ),
             str(retry_),
         )
@@ -230,8 +236,7 @@ def test___call___and_execute_success(self, sleep):
         target.assert_called_once_with("meep")
         sleep.assert_not_called()
 
-    # Make uniform return half of its maximum, which will be the calculated
-    # sleep time.
+    # Make uniform return half of its maximum, which is the calculated sleep time.
     @mock.patch("random.uniform", autospec=True, side_effect=lambda m, n: n / 2.0)
     @mock.patch("time.sleep", autospec=True)
     def test___call___and_execute_retry(self, sleep, uniform):
@@ -253,3 +258,55 @@ def test___call___and_execute_retry(self, sleep, uniform):
         target.assert_has_calls([mock.call("meep"), mock.call("meep")])
         sleep.assert_called_once_with(retry_._initial)
         assert on_error.call_count == 1
+
+    @mock.patch("time.sleep", autospec=True)
+    def test___init___without_retry_executed(self, sleep):
+        _some_function = mock.Mock()
+
+        retry_ = retry.Retry(
+            predicate=retry.if_exception_type(ValueError), on_error=_some_function
+        )
+        # check the proper creation of the class
+        assert retry_._on_error is _some_function
+
+        target = mock.Mock(spec=["__call__"], side_effect=[42])
+        # __name__ is needed by functools.partial.
+        target.__name__ = "target"
+
+        wrapped = retry_(target)
+
+        result = wrapped("meep")
+
+        assert result == 42
+        target.assert_called_once_with("meep")
+        sleep.assert_not_called()
+        _some_function.assert_not_called()
+
+    # Make uniform return half of its maximum, which is the calculated sleep time.
+    @mock.patch("random.uniform", autospec=True, side_effect=lambda m, n: n / 2.0)
+    @mock.patch("time.sleep", autospec=True)
+    def test___init___when_retry_is_executed(self, sleep, uniform):
+        _some_function = mock.Mock()
+
+        retry_ = retry.Retry(
+            predicate=retry.if_exception_type(ValueError), on_error=_some_function
+        )
+        # check the proper creation of the class
+        assert retry_._on_error is _some_function
+
+        target = mock.Mock(
+            spec=["__call__"], side_effect=[ValueError(), ValueError(), 42]
+        )
+        # __name__ is needed by functools.partial.
+        target.__name__ = "target"
+
+        wrapped = retry_(target)
+        target.assert_not_called()
+
+        result = wrapped("meep")
+
+        assert result == 42
+        assert target.call_count == 3
+        assert _some_function.call_count == 2
+        target.assert_has_calls([mock.call("meep"), mock.call("meep")])
+        sleep.assert_any_call(retry_._initial)