Fix concurrent modification errors in pusher metrics (#7106)

add a lock to try to make this metric actually work
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Richard van der Hoff 2020-03-19 11:28:49 +01:00 committed by GitHub
parent 8c75667ad7
commit e913823a22
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2 changed files with 19 additions and 9 deletions

1
changelog.d/7106.feature Normal file
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@ -0,0 +1 @@
Add prometheus metrics for the number of active pushers.

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@ -16,6 +16,7 @@
import logging import logging
from collections import defaultdict from collections import defaultdict
from threading import Lock
from typing import Dict, Tuple, Union from typing import Dict, Tuple, Union
from twisted.internet import defer from twisted.internet import defer
@ -56,12 +57,17 @@ class PusherPool:
# map from user id to app_id:pushkey to pusher # map from user id to app_id:pushkey to pusher
self.pushers = {} # type: Dict[str, Dict[str, Union[HttpPusher, EmailPusher]]] self.pushers = {} # type: Dict[str, Dict[str, Union[HttpPusher, EmailPusher]]]
# a lock for the pushers dict, since `count_pushers` is called from an different
# and we otherwise get concurrent modification errors
self._pushers_lock = Lock()
def count_pushers(): def count_pushers():
results = defaultdict(int) # type: Dict[Tuple[str, str], int] results = defaultdict(int) # type: Dict[Tuple[str, str], int]
for pushers in self.pushers.values(): with self._pushers_lock:
for pusher in pushers.values(): for pushers in self.pushers.values():
k = (type(pusher).__name__, pusher.app_id) for pusher in pushers.values():
results[k] += 1 k = (type(pusher).__name__, pusher.app_id)
results[k] += 1
return results return results
LaterGauge( LaterGauge(
@ -293,11 +299,12 @@ class PusherPool:
return return
appid_pushkey = "%s:%s" % (pusherdict["app_id"], pusherdict["pushkey"]) appid_pushkey = "%s:%s" % (pusherdict["app_id"], pusherdict["pushkey"])
byuser = self.pushers.setdefault(pusherdict["user_name"], {})
if appid_pushkey in byuser: with self._pushers_lock:
byuser[appid_pushkey].on_stop() byuser = self.pushers.setdefault(pusherdict["user_name"], {})
byuser[appid_pushkey] = p if appid_pushkey in byuser:
byuser[appid_pushkey].on_stop()
byuser[appid_pushkey] = p
# Check if there *may* be push to process. We do this as this check is a # Check if there *may* be push to process. We do this as this check is a
# lot cheaper to do than actually fetching the exact rows we need to # lot cheaper to do than actually fetching the exact rows we need to
@ -326,7 +333,9 @@ class PusherPool:
if appid_pushkey in byuser: if appid_pushkey in byuser:
logger.info("Stopping pusher %s / %s", user_id, appid_pushkey) logger.info("Stopping pusher %s / %s", user_id, appid_pushkey)
byuser[appid_pushkey].on_stop() byuser[appid_pushkey].on_stop()
del byuser[appid_pushkey] with self._pushers_lock:
del byuser[appid_pushkey]
yield self.store.delete_pusher_by_app_id_pushkey_user_id( yield self.store.delete_pusher_by_app_id_pushkey_user_id(
app_id, pushkey, user_id app_id, pushkey, user_id
) )