Fix synctl and duplicate worker spawning (#8798)

Synctl did not check if a worker thread was already running when using
`synctl start` and would naively start a fresh copy. This would
sometimes lead to cases where many duplicate copies of a single worker
would run.

This fix adds a pid check when starting worker threads and synctl will
now refuse to start individual workers if they're already running.
This commit is contained in:
Waylon Cude 2020-11-23 07:20:49 -08:00 committed by GitHub
parent 59a995f38d
commit 7127855741
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2 changed files with 8 additions and 0 deletions

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changelog.d/8798.bugfix Normal file
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@ -0,0 +1 @@
Fix a bug where synctl could spawn duplicate copies of a worker. Contributed by Waylon Cude.

7
synctl
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@ -358,6 +358,13 @@ def main():
for worker in workers:
env = os.environ.copy()
# Skip starting a worker if its already running
if os.path.exists(worker.pidfile) and pid_running(
int(open(worker.pidfile).read())
):
print(worker.app + " already running")
continue
if worker.cache_factor:
os.environ["SYNAPSE_CACHE_FACTOR"] = str(worker.cache_factor)