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Support celerycam for reconnecting db connenction if db connection is lost accidentally #550

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Support celerycam for reconnecting db connenction if db connection is lost accidentally #550

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2c9ab71
Force close connection and then reconnect when db connection is close…
jxltom Jul 6, 2018
2e52c37
Fixed typo
jxltom Jul 6, 2018
9415676
Compatible with flake8
jxltom Jul 6, 2018
bbd7ab9
Update djcelery/snapshot.py
auvipy May 20, 2025
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17 changes: 14 additions & 3 deletions djcelery/snapshot.py
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,8 @@
from datetime import timedelta

from django.conf import settings
from django.db import connection
from django.db.utils import InterfaceError

from celery import states
from celery.events.state import Task
Expand Down Expand Up @@ -127,9 +129,18 @@ def _handle_tasks():
for i, task in enumerate(state.tasks.items()):
self.handle_task(task)

for worker in state.workers.items():
self.handle_worker(worker)
_handle_tasks()
try:
for worker in state.workers.items():
self.handle_worker(worker)
_handle_tasks()
except InterfaceError as e:
# When connection already closed exception is raised,
# force to close connection and Django will automatically reconnect
if str(e) == 'connection already closed':
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Copilot AI May 13, 2025

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Comparing exception message strings is brittle; consider catching a more specific exception subclass or inspecting error attributes instead of matching on str(e).

Suggested change
if str(e) == 'connection already closed':
if getattr(e, 'args', None) and 'connection already closed' in e.args[0]:

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connection.close()
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Copilot AI May 13, 2025

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The try/except block wraps both worker and task handling, which may swallow unrelated errors. Consider narrowing the scope to only the database operations that need reconnection.

Suggested change
try:
for worker in state.workers.items():
self.handle_worker(worker)
_handle_tasks()
except InterfaceError as e:
# When connection already closed exception is raised,
# force to close connection and Django will automatically reconnect
if str(e) == 'connection already closed':
connection.close()
for worker in state.workers.items():
self.handle_worker(worker)
_handle_tasks()
try:
# Check and handle database reconnection if needed
connection.close()
except InterfaceError as e:
# When connection already closed exception is raised,
# force to close connection and Django will automatically reconnect
if str(e) == 'connection already closed':

Copilot uses AI. Check for mistakes.

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Copilot AI May 20, 2025

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Instead of calling connection.close() directly, use django.db.close_old_connections() to properly handle connection pooling and ensure thread safety according to Django's recommendations.

Suggested change
connection.close()
close_old_connections()

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logger.info(
'Django db connection is closed and will reconnect'
)

def on_cleanup(self):
expired = (self.TaskState.objects.expire_by_states(states, expires)
Expand Down