diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 1caef70538..bb22494965 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -49,6 +49,7 @@ from synapse.types import JsonDict
from synapse.util import unwrapFirstError
from synapse.util.async_helpers import yieldable_gather_results
from synapse.util.batching_queue import BatchingQueue
+from synapse.util.caches.descriptors import cached
from synapse.util.retryutils import NotRetryingDestination
if TYPE_CHECKING:
@@ -189,9 +190,38 @@ class Keyring:
valid_until_ts=2**63, # fake future timestamp
)
+ self._client = hs.get_federation_http_client()
+
+ @cached()
async def is_server_linearized(self, server_name: str) -> bool:
- # TODO(LM) Fetch whether the key response of the origin contains m.linearized.
- return not self._is_mine_server_name(server_name)
+ # TODO(LM) Cache this in the database.
+ # TODO(LM) Support perspectives server.
+ try:
+ response = await self._client.get_json(
+ destination=server_name,
+ path="/_matrix/key/v2/server",
+ ignore_backoff=True,
+ # we only give the remote server 10s to respond. It should be an
+ # easy request to handle, so if it doesn't reply within 10s, it's
+ # probably not going to.
+ #
+ # Furthermore, when we are acting as a notary server, we cannot
+ # wait all day for all of the origin servers, as the requesting
+ # server will otherwise time out before we can respond.
+ #
+ # (Note that get_json may make 4 attempts, so this can still take
+ # almost 45 seconds to fetch the headers, plus up to another 60s to
+ # read the response).
+ timeout=10000,
+ )
+ except (NotRetryingDestination, RequestSendFailed) as e:
+ # these both have str() representations which we can't really improve
+ # upon
+ raise KeyLookupError(str(e))
+ except HttpResponseException as e:
+ raise KeyLookupError("Remote server returned an error: %s" % (e,))
+
+ return response.get("m.linearized", False)
async def verify_json_for_server(
self,
|
