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".
pull/5836/head
Erik Johnston 2019-08-06 16:27:46 +01:00
parent d1b5b055be
commit af9f1c0764
2 changed files with 6 additions and 2 deletions

View File

@ -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)

View File

@ -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")