suppose I am running a worker dyno with following python code in heroku
import time
time.sleep(60*60)
exit()
I want to stop the worker completely, this code ends the program, but it starts again having the same effect as heroku ps:restart worker what should I write in the code to have the same effect as heroku ps:scale worker=0, is this possible ? If not what are my alternatives ?
The worker processes defined in your Procfile should be always-on workers, same as the web-processes you define in there.
For one-off tasks that exit afterwards you can use a one-off worker dyno. You can also easily define them in the Heroku scheduler.
Related
I am building a app and I am trying to run some tasks everyday. So I saw some answers, blogs and tutorials about using celery, So I liked the idea of using celery for doing background jobs.
But I have some questions about celery :-
As mentioned in Celery Documentation that after setting a celery task , I have to run a command like celery -A proj worker -l INFO which will process all the tasks and after command it will run the tasks, so my question is , I have to stop the running server to execute this command and
what if I deploy Django project with celery on Heroku or Python Anywhere.
Should I have to run command every time Or I can execute this command first then i can start the server ?
If I have to run this command every time to perform background tasks then how is this possible when deploying to Heroku,
Will celery's background tasks will remain running after executing python manage.py run server in only terminal ?
Why I am in doubt ? :-
What I think is, When running celery -A proj worker -l INFO it will process (or Run) the tasks and I cannot execute run server in one terminal.
Any help would be much Appreciated. Thank You
Should I have to run command every time Or I can execute this command first then i can start the server ?
Dockerize your Celecry and write your own script for auto-run.
You can't run celery worker and django application in one terminal simultaneously, because both of them are programs that should be running in parallel. So you should use two terminals, one for django and another for celery worker.
I highly recommend to read this heroku development article for using Celery and Django on heroku.
I'm new to RQ and am trying to use it for a job which will run in the background. I have managed to set it up, and I'm also able to start more than one worker.
Now I'm trying to run these workers concurrently. I installed supervisor and followed a tutorial to add programs to it, and it worked.
Here is my supervisor configuration:
[program:rqworker]
command=/usr/local/bin/rq worker mysql
process_name=rqworker1-%(process_num)s
numprocs=3
directory=/home/hp/Python/sample
stopsignal=TERM
autostart=true
autorestart=true
stdout_logfile=/home/hp/Python/sample/logs
The worker function is present in the sample directory mentioned above.
The problem is that even after specifying numprocs as 3 in the config file, the workers do not run in parallel.
Here are some screenshots, which show that although multiple workers have been started, they do not work in parallel.
Also, I saw this stackoverflow answer, but it still doesn't divide the jobs amongst the workers!
Could anyone tell me what is wrong with this configuration/what I need to change?
I found the problem; it wasn't with supervisor or rqworker. The manager program was blocking concurrency, by waiting for task completion!
I start the worker by executing the following in the terminal:
celery -A cel_test worker --loglevel=INFO --concurrency=10 -n worker1.%h
Then I get a long looping error message stating that celery has received an unregistered task and has triggered:
KeyError: 'cel_test.grp_all_w_codes.mk_dct' #this is the name of the task
The problem with this is that cel_test.grp_all_w_codes.mk_dct doesn't exist. In fact there isn't even a module cel_test.grp_all_w_codes let alone the task mk_dct. There was once a few days ago but I've since deleted it. I thought maybe there was a .pyc file floating around but there isn't. I also can't find a single reference in my code to the task that's throwing the error. I shut down my computer and restarted the rabbitmq server thinking maybe a reference to something was just stuck in memory but it did not help.
Does anyone have any idea what could be the problem here or what I'm missing?
Well, without knowing your conf files, I can see two reasons that would provoke this:
the mk_dct task wasn't completed when you stopped the worker and delete the module. If you're running with CELERY_ACKS_LATE, it will try to relaunch the task everytime you re run the worker. Try remove this setting, or launch the worker with the purge option.
celery -A cel_test worker --loglevel=INFO --concurrency=10 -n worker1.%h --purge
the mk_dct task is launched by your celery beat. If so, try relaunching celery beat and clearing it's database backend if you had a custom one.
If it does not solve the problem, please post your celery conf, and make sure you have cleaned all the .pyc of your project and restarted everything.
I'm currently writing a flask application and going to use openshift. I start my worker in my dev environment using
celery worker -A wsgi.app
My question is how do I start my celery worker in openshift? Because if I started in the openshift shell when I exit the shell the process is killed and my background workers never run so the flask application never runs correctly.
I really appreciate any help. Thanks.
Why can't try like this
celery multi start worker1 \
--pidfile="$HOME/run/celery/%n.pid" \
--logfile="$HOME/log/celery/%n.log"
where mentioned here
I have written an Upstart job to run celery in my Ubuntu server. Here's my configuration file called celeryd.conf
# celeryd - runs the celery daemon
#
# This task is run on startup to run the celery daemon
description "run celery daemon"
start on startup
expect fork
respawn
exec su - trakklr -c "/app/trakklr/src/trakklr celeryd --events --beat --loglevel=debug --settings=production"
When I execute sudo service celeryd start, the celeryd process starts just fine and all the x number of worker process start fine.
..but when I execute, sudo service celeryd stop, it stops most of the processes but a few processes are left hanging.
Why is this happening? I'm using Celery 2.5.3.
Here's an issue from the Github tracker.
https://github.com/celery/django-celery/issues/142
I still use init.d to run celery so this may not apply. With that in mind, stopping the celery service sends the TERM signal to celery. This tells the workers not to accept new tasks but it does not terminate existing tasks. Therefore, depending on how long your tasks take to execute you may see tasks for some time after telling celery to stop. Eventually, they will all shut down unless you have some other problem.
I wasn't able to figure this out but it seemed to be an issue with my older celery version. I found this issue mentioned on their issue-tracker and I guess it points to the same issue:
https://github.com/celery/django-celery/issues/142
I upgraded my celery and django-celery to the 3.x.x versions and this issue was gone.