Convert remote key resource REST layer to async/await. (#7020)

changelog.d/7020.misc

+Port `synapse.rest.keys` to async/await.

synapse/rest/key/v2/remote_key_resource.py

@@ -18,8 +18,6 @@ from typing import Dict, Set
 from canonicaljson import encode_canonical_json, json
 from signedjson.sign import sign_json
 
-from twisted.internet import defer
-
 from synapse.api.errors import Codes, SynapseError
 from synapse.crypto.keyring import ServerKeyFetcher
 from synapse.http.server import (
@@ -125,8 +123,7 @@ class RemoteKey(DirectServeResource):
 
         await self.query_keys(request, query, query_remote_on_cache_miss=True)
 
-    @defer.inlineCallbacks
-    def query_keys(self, request, query, query_remote_on_cache_miss=False):
+    async def query_keys(self, request, query, query_remote_on_cache_miss=False):
         logger.info("Handling query for keys %r", query)
 
         store_queries = []
@@ -143,7 +140,7 @@ class RemoteKey(DirectServeResource):
             for key_id in key_ids:
                 store_queries.append((server_name, key_id, None))
 
-        cached = yield self.store.get_server_keys_json(store_queries)
+        cached = await self.store.get_server_keys_json(store_queries)
 
         json_results = set()
 
@@ -215,8 +212,8 @@ class RemoteKey(DirectServeResource):
                     json_results.add(bytes(result["key_json"]))
 
         if cache_misses and query_remote_on_cache_miss:
-            yield self.fetcher.get_keys(cache_misses)
-            yield self.query_keys(request, query, query_remote_on_cache_miss=False)
+            await self.fetcher.get_keys(cache_misses)
+            await self.query_keys(request, query, query_remote_on_cache_miss=False)
         else:
             signed_keys = []
             for key_json in json_results: