Add type hints for HTTP and email pushers. (#8880)

synapse/push/pusherpool.py

@@ -15,7 +15,7 @@
 # limitations under the License.
 
 import logging
-from typing import TYPE_CHECKING, Dict, Union
+from typing import TYPE_CHECKING, Any, Dict, Optional
 
 from prometheus_client import Gauge
 
@@ -23,9 +23,7 @@ from synapse.metrics.background_process_metrics import (
     run_as_background_process,
     wrap_as_background_process,
 )
-from synapse.push import PusherConfigException
-from synapse.push.emailpusher import EmailPusher
-from synapse.push.httppusher import HttpPusher
+from synapse.push import Pusher, PusherConfigException
 from synapse.push.pusher import PusherFactory
 from synapse.types import RoomStreamToken
 from synapse.util.async_helpers import concurrently_execute
@@ -77,7 +75,7 @@ class PusherPool:
         self._last_room_stream_id_seen = self.store.get_room_max_stream_ordering()
 
         # map from user id to app_id:pushkey to pusher
-        self.pushers = {}  # type: Dict[str, Dict[str, Union[HttpPusher, EmailPusher]]]
+        self.pushers = {}  # type: Dict[str, Dict[str, Pusher]]
 
     def start(self):
         """Starts the pushers off in a background process.
@@ -99,11 +97,11 @@ class PusherPool:
         lang,
         data,
         profile_tag="",
-    ):
+    ) -> Optional[Pusher]:
         """Creates a new pusher and adds it to the pool
 
         Returns:
-            EmailPusher|HttpPusher
+            The newly created pusher.
         """
 
         time_now_msec = self.clock.time_msec()
@@ -267,17 +265,19 @@ class PusherPool:
         except Exception:
             logger.exception("Exception in pusher on_new_receipts")
 
-    async def start_pusher_by_id(self, app_id, pushkey, user_id):
+    async def start_pusher_by_id(
+        self, app_id: str, pushkey: str, user_id: str
+    ) -> Optional[Pusher]:
         """Look up the details for the given pusher, and start it
 
         Returns:
-            EmailPusher|HttpPusher|None: The pusher started, if any
+            The pusher started, if any
         """
         if not self._should_start_pushers:
-            return
+            return None
 
         if not self._pusher_shard_config.should_handle(self._instance_name, user_id):
-            return
+            return None
 
         resultlist = await self.store.get_pushers_by_app_id_and_pushkey(app_id, pushkey)
 
@@ -303,19 +303,19 @@ class PusherPool:
 
         logger.info("Started pushers")
 
-    async def _start_pusher(self, pusherdict):
+    async def _start_pusher(self, pusherdict: Dict[str, Any]) -> Optional[Pusher]:
         """Start the given pusher
 
         Args:
-            pusherdict (dict): dict with the values pulled from the db table
+            pusherdict: dict with the values pulled from the db table
 
         Returns:
-            EmailPusher|HttpPusher
+            The newly created pusher or None.
         """
         if not self._pusher_shard_config.should_handle(
             self._instance_name, pusherdict["user_name"]
         ):
-            return
+            return None
 
         try:
             p = self.pusher_factory.create_pusher(pusherdict)
@@ -328,15 +328,15 @@ class PusherPool:
                 pusherdict.get("pushkey"),
                 e,
             )
-            return
+            return None
         except Exception:
             logger.exception(
                 "Couldn't start pusher id %i: caught Exception", pusherdict["id"],
             )
-            return
+            return None
 
         if not p:
-            return
+            return None
 
         appid_pushkey = "%s:%s" % (pusherdict["app_id"], pusherdict["pushkey"])