diff options
Diffstat (limited to 'synapse/http/federation/well_known_resolver.py')
| -rw-r--r-- | synapse/http/federation/well_known_resolver.py | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/synapse/http/federation/well_known_resolver.py b/synapse/http/federation/well_known_resolver.py index c846003886..5e9b0befb0 100644 --- a/synapse/http/federation/well_known_resolver.py +++ b/synapse/http/federation/well_known_resolver.py @@ -32,8 +32,8 @@ from synapse.util.metrics import Measure # period to cache .well-known results for by default WELL_KNOWN_DEFAULT_CACHE_PERIOD = 24 * 3600 -# jitter to add to the .well-known default cache ttl -WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 10 * 60 +# jitter factor to add to the .well-known default cache ttls +WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 0.1 # period to cache failure to fetch .well-known for WELL_KNOWN_INVALID_CACHE_PERIOD = 1 * 3600 @@ -133,16 +133,14 @@ class WellKnownResolver(object): # We have recently seen a valid well-known record for this # server, so we cache the lack of well-known for a shorter time. cache_period = WELL_KNOWN_DOWN_CACHE_PERIOD - cache_period += random.uniform( - 0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER - ) else: - # add some randomness to the TTL to avoid a stampeding herd every hour - # after startup cache_period = WELL_KNOWN_INVALID_CACHE_PERIOD - cache_period += random.uniform( - 0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER - ) + + # add some randomness to the TTL to avoid a stampeding herd + cache_period *= random.uniform( + 1 - WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER, + 1 + WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER, + ) if cache_period > 0: self._well_known_cache.set(server_name, result, cache_period) @@ -194,7 +192,10 @@ class WellKnownResolver(object): cache_period = WELL_KNOWN_DEFAULT_CACHE_PERIOD # add some randomness to the TTL to avoid a stampeding herd every 24 hours # after startup - cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER) + cache_period *= random.uniform( + 1 - WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER, + 1 + 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) |