Query missing cross-signing keys on local sig upload

Add changelog

Save retrieved keys to the db

lint

Fix and de-brittle remote result dict processing

Use query_user_devices instead, assume only master, self_signing key types

Make changelog more useful

Remove very specific exception handling

Wrap get_verify_key_from_cross_signing_key in a try/except

Note that _get_e2e_cross_signing_verify_key can raise a SynapseError

lint

Add comment explaining why this is useful

Only fetch master and self_signing key types

Fix log statements, docstrings

Remove extraneous items from remote query try/except

lint

Factor key retrieval out into a separate function

Send device updates, modeled after SigningKeyEduUpdater._handle_signing_key_updates

Update method docstring

synapse/federation/transport/client.py

@@ -406,13 +406,19 @@ class TransportLayerClient(object):
               "device_keys": {
                 "<user_id>": {
                   "<device_id>": {...}
+              } }
+              "master_keys": {
+                "<user_id>": {...}
+              } }
+              "self_signing_keys": {
+                "<user_id>": {...}
             } } }
 
         Args:
             destination(str): The server to query.
             query_content(dict): The user ids to query.
         Returns:
-            A dict containg the device keys.
+            A dict containing device and cross-signing keys.
         """
         path = _create_v1_path("/user/keys/query")
 
@@ -429,14 +435,16 @@ class TransportLayerClient(object):
         Response:
             {
               "stream_id": "...",
-              "devices": [ { ... } ]
+              "devices": [ { ... } ],
+              "master_key": { ... },
+              "self_signing_key: { ... }
             }
 
         Args:
             destination(str): The server to query.
             query_content(dict): The user ids to query.
         Returns:
-            A dict containg the device keys.
+            A dict containing device and cross-signing keys.
         """
         path = _create_v1_path("/user/devices/%s", user_id)