feat(pubsub): allow disabling ack deadline fetch (talkiq#898)

Author: shaundialpad

pubsub/gcloud/aio/pubsub/__init__.py

@@ -53,6 +53,7 @@ async def handler(message):
         'projects/<my_project>/subscriptions/<my_subscription>',
         handler,
         subscriber_client,
+        ack_deadline=10,
         num_producers=1,
         max_messages_per_producer=100,
         ack_window=0.3,
@@ -70,6 +71,11 @@ async def handler(message):
   return ``None`` if the message should be acked. An exception raised within
   the handler will result in the message being left to expire, and thus it will
   be redelivered according to your subscription's ack deadline.
+- ``ack_deadline``: An optional parameter which should match the ack deadline
+  (in seconds) of your subscription. If omitted, the library will fetch the
+  current value from the subscription. Hard-coding it here is a way to avoid an
+  extra call to the Pub/Sub REST API which counts as an Administrator
+  Operation.
 - ``num_producers``: Number of workers that will be making ``pull`` requests to
   pubsub. Please note that a worker will only fetch new batch once the
   ``handler`` was called for each message from the previous batch. This means

pubsub/gcloud/aio/pubsub/subscriber.py

@@ -41,12 +41,13 @@ class AckDeadlineCache:
         def __init__(
             self, subscriber_client: SubscriberClient,
             subscription: str, cache_timeout: float,
+            ack_deadline: Optional[float] = None,
         ):
             self.subscriber_client = subscriber_client
             self.subscription = subscription
             self.cache_timeout = cache_timeout
-            self.ack_deadline: float = float('inf')
             self.last_refresh: float = float('-inf')
+            self.ack_deadline = ack_deadline or float('inf')
 
         async def get(self) -> float:
             if self.cache_outdated():
@@ -469,6 +470,7 @@ async def subscribe(
         num_producers: int = 1,
         max_messages_per_producer: int = 100,
         ack_window: float = 0.3,
+        ack_deadline: Optional[float] = None,
         ack_deadline_cache_timeout: float = float('inf'),
         num_tasks_per_consumer: int = 1,
         enable_nack: bool = True,
@@ -484,6 +486,7 @@ async def subscribe(
             subscriber_client,
             subscription,
             ack_deadline_cache_timeout,
+            ack_deadline,
         )
 
         if metrics_client is not None:

pubsub/pyproject.rest.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "gcloud-rest-pubsub"
-version = "6.1.0"
+version = "6.2.0"
 description = "Python Client for Google Cloud Pub/Sub"
 readme = "README.rst"
 

pubsub/pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "gcloud-aio-pubsub"
-version = "6.1.0"
+version = "6.2.0"
 description = "Python Client for Google Cloud Pub/Sub"
 readme = "README.rst"
 

pubsub/tests/unit/subscriber_test.py

@@ -1,4 +1,5 @@
 # pylint: disable=redefined-outer-name
+# pylint: disable=too-many-lines
 from gcloud.aio.auth import BUILD_GCLOUD_REST
 
 # pylint: disable=too-complex
@@ -148,6 +149,16 @@ async def test_ack_deadline_cache_get_calls_refresh_first_time(
         assert await cache.get() == 42
         assert cache.last_refresh
 
+    @pytest.mark.asyncio
+    async def test_ack_deadline_cache_no_refresh_if_specified(
+        subscriber_client,
+    ):
+        cache = AckDeadlineCache(
+            subscriber_client, 'fake_subscription', float('inf'), 100
+        )
+        assert await cache.get() == 100
+        subscriber_client.get_subscription.assert_not_called()
+
     @pytest.mark.asyncio
     async def test_ack_deadline_cache_get_no_call_if_not_outdated(
         subscriber_client,