From af9f1c07646031bf267aa20f2629d5b96c6603b6 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Tue, 6 Aug 2019 16:27:46 +0100 Subject: [PATCH] Add a lower bound for TTL on well known results. It costs both us and the remote server for us to fetch the well known for every single request we send, so we add a minimum cache period. This is set to 5m so that we still honour the basic premise of "refetch frequently". --- synapse/http/federation/matrix_federation_agent.py | 4 ++++ tests/http/federation/test_matrix_federation_agent.py | 4 ++-- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py index a0d513983..79e488c94 100644 --- a/synapse/http/federation/matrix_federation_agent.py +++ b/synapse/http/federation/matrix_federation_agent.py @@ -47,6 +47,9 @@ WELL_KNOWN_INVALID_CACHE_PERIOD = 1 * 3600 # cap for .well-known cache period WELL_KNOWN_MAX_CACHE_PERIOD = 48 * 3600 +# lower bound for .well-known cache period +WELL_KNOWN_MIN_CACHE_PERIOD = 5 * 60 + logger = logging.getLogger(__name__) well_known_cache = TTLCache("well-known") @@ -356,6 +359,7 @@ class MatrixFederationAgent(object): cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER) else: cache_period = min(cache_period, WELL_KNOWN_MAX_CACHE_PERIOD) + cache_period = max(cache_period, WELL_KNOWN_MIN_CACHE_PERIOD) return (result, cache_period) diff --git a/tests/http/federation/test_matrix_federation_agent.py b/tests/http/federation/test_matrix_federation_agent.py index 4255add09..5e709c0c1 100644 --- a/tests/http/federation/test_matrix_federation_agent.py +++ b/tests/http/federation/test_matrix_federation_agent.py @@ -953,7 +953,7 @@ class MatrixFederationAgentTests(TestCase): well_known_server = self._handle_well_known_connection( client_factory, expected_sni=b"testserv", - response_headers={b"Cache-Control": b"max-age=10"}, + response_headers={b"Cache-Control": b"max-age=1000"}, content=b'{ "m.server": "target-server" }', ) @@ -969,7 +969,7 @@ class MatrixFederationAgentTests(TestCase): self.assertEqual(r, b"target-server") # expire the cache - self.reactor.pump((10.0,)) + self.reactor.pump((1000.0,)) # now it should connect again fetch_d = self.do_get_well_known(b"testserv")