Fix concurrent modification errors in pusher metrics (#7106)

add a lock to try to make this metric actually work
pull/7107/head
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
from collections import defaultdict
from threading import Lock
from typing import Dict, Tuple, Union
from twisted.internet import defer
@ -56,12 +57,17 @@ class PusherPool:
# map from user id to app_id:pushkey to pusher
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():
results = defaultdict(int) # type: Dict[Tuple[str, str], int]
for pushers in self.pushers.values():
for pusher in pushers.values():
k = (type(pusher).__name__, pusher.app_id)
results[k] += 1
with self._pushers_lock:
for pushers in self.pushers.values():
for pusher in pushers.values():
k = (type(pusher).__name__, pusher.app_id)
results[k] += 1
return results
LaterGauge(
@ -293,11 +299,12 @@ class PusherPool:
return
appid_pushkey = "%s:%s" % (pusherdict["app_id"], pusherdict["pushkey"])
byuser = self.pushers.setdefault(pusherdict["user_name"], {})
if appid_pushkey in byuser:
byuser[appid_pushkey].on_stop()
byuser[appid_pushkey] = p
with self._pushers_lock:
byuser = self.pushers.setdefault(pusherdict["user_name"], {})
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
# lot cheaper to do than actually fetching the exact rows we need to
@ -326,7 +333,9 @@ class PusherPool:
if appid_pushkey in byuser:
logger.info("Stopping pusher %s / %s", user_id, appid_pushkey)
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(
app_id, pushkey, user_id
)