fix: update resume token for restarting BiDi streams (#10282)

Author: crwilcox

google/cloud/firestore_v1/watch.py

@@ -213,9 +213,9 @@ def __init__(
         self._closing = threading.Lock()
         self._closed = False
 
-        initial_request = firestore_pb2.ListenRequest(
-            database=self._firestore._database_string, add_target=self._targets
-        )
+        self.resume_token = None
+
+        rpc_request = self._get_rpc_request
 
         if ResumableBidiRpc is None:
             ResumableBidiRpc = self.ResumableBidiRpc  # FBO unit tests
@@ -224,7 +224,7 @@ def __init__(
             self._api.transport.listen,
             should_recover=_should_recover,
             should_terminate=_should_terminate,
-            initial_request=initial_request,
+            initial_request=rpc_request,
             metadata=self._firestore._rpc_metadata,
         )
 
@@ -252,13 +252,19 @@ def __init__(
         self.has_pushed = False
 
         # The server assigns and updates the resume token.
-        self.resume_token = None
         if BackgroundConsumer is None:  # FBO unit tests
             BackgroundConsumer = self.BackgroundConsumer
 
         self._consumer = BackgroundConsumer(self._rpc, self.on_snapshot)
         self._consumer.start()
 
+    def _get_rpc_request(self):
+        if self.resume_token is not None:
+            self._targets["resume_token"] = self.resume_token
+        return firestore_pb2.ListenRequest(
+            database=self._firestore._database_string, add_target=self._targets
+        )
+
     @property
     def is_active(self):
         """bool: True if this manager is actively streaming.

tests/unit/v1/test_watch.py

@@ -776,6 +776,12 @@ def test__reset_docs(self):
         self.assertEqual(inst.resume_token, None)
         self.assertFalse(inst.current)
 
+    def test_resume_token_sent_on_recovery(self):
+        inst = self._makeOne()
+        inst.resume_token = b"ABCD0123"
+        request = inst._get_rpc_request()
+        self.assertEqual(request.add_target.resume_token, b"ABCD0123")
+
 
 class DummyFirestoreStub(object):
     def Listen(self):  # pragma: NO COVER
@@ -922,7 +928,7 @@ def __init__(
         self.start_rpc = start_rpc
         self.should_recover = should_recover
         self.should_terminate = should_terminate
-        self.initial_request = initial_request
+        self.initial_request = initial_request()
         self.metadata = metadata
         self.closed = False
         self.callbacks = []