add comment about why unreg

This commit is contained in:
Amber Brown 2018-05-28 19:14:41 +10:00
parent a2eb5db4a0
commit 357c74a50f

View file

@ -41,6 +41,8 @@ response_cache_total = Gauge("synapse_util_caches_response_cache:total", "", ["n
def register_cache(cache_type, cache_name, cache):
# Check if the metric is already registered. Unregister it, if so.
# This usually happens during tests, as at runtime these caches are
# effectively singletons.
metric_name = "cache_%s_%s" % (cache_type, cache_name)
if metric_name in collectors_by_name.keys():
REGISTRY.unregister(collectors_by_name[metric_name])