Remove log_function and its uses (#11761)

I've never found this terribly useful. I think it was added in the early days
of Synapse, without much thought as to what would actually be useful to log,
and has just been cargo-culted ever since.

Rather, it tends to clutter up debug logs with useless information.

changelog.d/11761.misc

@@ -0,0 +1 @@
+Remove `log_function` utility function and its uses.

synapse/federation/federation_client.py

@@ -56,7 +56,6 @@
 from synapse.events import EventBase, builder
 from synapse.federation.federation_base import FederationBase, event_from_pdu_json
 from synapse.federation.transport.client import SendJoinResponse
-from synapse.logging.utils import log_function
 from synapse.types import JsonDict, get_domain_from_id
 from synapse.util.async_helpers import concurrently_execute
 from synapse.util.caches.expiringcache import ExpiringCache
@@ -144,7 +143,6 @@ def _clear_tried_cache(self) -> None:
             if destination_dict:
                 self.pdu_destination_tried[event_id] = destination_dict
 
-    @log_function
     async def make_query(
         self,
         destination: str,
@@ -178,7 +176,6 @@ async def make_query(
             ignore_backoff=ignore_backoff,
         )
 
-    @log_function
     async def query_client_keys(
         self, destination: str, content: JsonDict, timeout: int
     ) -> JsonDict:
@@ -196,7 +193,6 @@ async def query_client_keys(
             destination, content, timeout
         )
 
-    @log_function
     async def query_user_devices(
         self, destination: str, user_id: str, timeout: int = 30000
     ) -> JsonDict:
@@ -208,7 +204,6 @@ async def query_user_devices(
             destination, user_id, timeout
         )
 
-    @log_function
     async def claim_client_keys(
         self, destination: str, content: JsonDict, timeout: int
     ) -> JsonDict:

synapse/federation/federation_server.py

@@ -58,7 +58,6 @@
     run_in_background,
 )
 from synapse.logging.opentracing import log_kv, start_active_span_from_edu, trace
-from synapse.logging.utils import log_function
 from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.replication.http.federation import (
     ReplicationFederationSendEduRestServlet,
@@ -859,7 +858,6 @@ async def on_event_auth(
             res = {"auth_chain": [a.get_pdu_json(time_now) for a in auth_pdus]}
         return 200, res
 
-    @log_function
     async def on_query_client_keys(
         self, origin: str, content: Dict[str, str]
     ) -> Tuple[int, Dict[str, Any]]:
@@ -940,7 +938,6 @@ async def on_get_missing_events(
 
         return {"events": [ev.get_pdu_json(time_now) for ev in missing_events]}
 
-    @log_function
     async def on_openid_userinfo(self, token: str) -> Optional[str]:
         ts_now_ms = self._clock.time_msec()
         return await self.store.get_user_id_for_open_id_token(token, ts_now_ms)

synapse/federation/persistence.py

@@ -23,7 +23,6 @@
 from typing import Optional, Tuple
 
 from synapse.federation.units import Transaction
-from synapse.logging.utils import log_function
 from synapse.storage.databases.main import DataStore
 from synapse.types import JsonDict
 
@@ -36,7 +35,6 @@ class TransactionActions:
     def __init__(self, datastore: DataStore):
         self.store = datastore
 
-    @log_function
     async def have_responded(