Diskcache doesn't work after trying redis/celery

Dash Python
1

Hi guys,

I was working with diskcache on Dev mode, but when I switched to the Prod I decided to try celery/redis.
Unfortunately I run into some problems with celery, and when I decided to switch back to diskcache I got the following error :

[2022-07-14 10:53:57 +0100] [22893] [INFO] Starting gunicorn 20.1.0
[2022-07-14 10:53:57 +0100] [22893] [INFO] Listening at: http://127.0.0.1:8020 (22893)
[2022-07-14 10:53:57 +0100] [22893] [INFO] Using worker: sync
[2022-07-14 10:53:57 +0100] [22896] [INFO] Booting worker with pid: 22896
Exception on /_dash-update-component [POST]
Traceback (most recent call last):
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/flask/app.py”, line 2077, in wsgi_app
response = self.full_dispatch_request()
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/flask/app.py”, line 1525, in full_dispatch_request
rv = self.handle_user_exception(e)
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/flask/app.py”, line 1523, in full_dispatch_request
rv = self.dispatch_request()
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/flask/app.py”, line 1509, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/dash/dash.py”, line 1472, in dispatch
response.set_data(func(*args, outputs_list=outputs_list))
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/dash/_callback.py”, line 151, in add_context
output_value = func(*func_args, **func_kwargs) # %% callback invoked %%
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/dash/dash.py”, line 1356, in callback
callback_manager.terminate_unhealthy_job(pending_job)
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/dash/long_callback/managers/diskcache_manager.py”, line 81, in terminate_unhealthy_job
if job and psutil.pid_exists(job):
File “/home/amiri/anaconda3/envs/acp_manque_production/lib/python3.7/site-packages/psutil/init.py”, line 1379, in pid_exists
if pid < 0:
TypeError: ‘<’ not supported between instances of ‘str’ and ‘int’

The pid that triggers the error looks like this : 748e46d9-4056-4c80-9ea0-6e4785fa06ed
The problem seems to go away when I don’t work with gunicorn or when I change its port.

This is my code:

cache = diskcache.Cache("./cache")
long_callback_manager = DiskcacheLongCallbackManager(cache, expire=60)

app = Dash(__name__, external_stylesheets=[dbc.themes.BOOTSTRAP], 
           long_callback_manager=long_callback_manager, prevent_initial_callbacks=True)

server = app.server

# Setting the layout
app.layout = html.Div([navbar, 
                       main_layout, 
                       toast, 
                       modal,
                       dcc.Interval(id="main-callback-interval", interval=60000)])

# Update dashboard
main_callback_dashapp(app)

if __name__ == '__main__':
    app.run_server()

Thanks in advance.