HowTo

A Curated list on How-To's, ranging from any and all JS, Python, Django. Feel free to use all the snippets here for whatever functionality/scenario. I hope this becomes helpful! Contribute, contribute, contribute!

1. How to Render A Datepicker Widget on Multiple Input Fields

Say you want several input fields to have a datepicker widget, without explicitly defining the inputs for each one, or for the case where the input fields are generated dynamically, a possible fix (using jQuery) is written below:

    
    <script>
		$(document).ready(function () {
			$('body').on('focus',".dateinput", function(){
				$(this).datepicker();
			});
		})
	</script>

Whereby dateinput is the class of the input fields. The complete markup is coming. Where I found this useful: I had input fields that needed datepicker widgets within Django Formsets.

2. How to find if today is in a range of given dates

Say you hava an object with 2 Date attributes start_date and end_date and you would like to find the dates between the 2 dates:

	# Somewhere in your views.py
	from datetime import date, timedelta
	
	def daterange(start_date, end_date):
            """
            Function to find all dates within a particular range of 2 dates
   	    """
    	    for n in range(int ((end_date - start_date).days)+1):
	        yield start_date + timedelta(n)
			
			
	def your_view(request):
	    # Logic here, for capturing the 2 dates and assigning them names, i.e. start_date and end_date
	     now = date.today()  #Finding today's date
	     if now in daterange(start_date, end_date): 
                # Logic for if the date today is among the dates
             else:
                # Logic for if date today is not among the dates

3. Celery + Django

4 How to run celery as a daemon?

1. Create /etc/init.d/celeryd with the content from the celery repo

2. Make celeryd executable

sudo nano /etc/init.d/celeryd

Copy-paste code from celery repo to the file

Save celeryd (CTR+X, y, Enter from nano)

Run following commands from the terminal:

sudo chmod 755 /etc/init.d/celeryd
sudo chown root:root /etc/init.d/celeryd

1.2. Configuration

What to do?

1. Create /etc/default/celeryd
2. Configure it

How?

sudo nano /etc/default/celeryd

Configure it depending on what you need. Options and template can be found in the docs

My example:

CELERY_BIN="project/venv/bin/celery" # App instance to use
CELERY_APP="project_django_project" # Where to chdir at start.
CELERYD_CHDIR="/home/username/project/" # Extra command-line arguments to the worker
CELERYD_OPTS="--time-limit=300 --concurrency=8" # %n will be replaced with the first part of the nodename.
CELERYD_LOG_FILE="/var/log/celery/%n%I.log"
CELERYD_PID_FILE="/var/run/celery/%n.pid" # Workers should run as an unprivileged user.
# You need to create this user manually (or you can choose
# a user/group combination that already exists (e.g., nobody).
CELERYD_USER="username"
CELERYD_GROUP="username" # If enabled pid and log directories will be created if missing,
# and owned by the userid/group configured.
CELERY_CREATE_DIRS=1 export SECRET_KEY="foobar"

Note

You can set your environment variables in /etc/default/celeryd. For moreinfo about environment variable take a look at this SOanswer

Test it

You can check if the worker is active by:

sudo /etc/init.d/celeryd start
sudo /etc/init.d/celeryd status

Don't forget to stop the worker:

sudo /etc/init.d/celeryd stop 

2. Init-script: celerybeat

1. Create /etc/init.d/celerybeat with the content from celery repo

2. Make celerybeat executable

sudo nano /etc/init.d/celerybeat

Copy-paste code from celeryrepo to the file

Save celerybeat (CTR+X, y, Enter from nano)

Run following commands from the terminal:

sudo chmod 755 /etc/init.d/celerybeat
sudo chown root:root /etc/init.d/celerybeat

2.2. Configuration

What to do?

Configurate either /etc/default/celerybeat or stick with /etc/default/celeryd

How?

sudo nano /etc/default/celerybeat

Configure it depending on what you need. Options and template can be fount inthe docs

Note

If you don't require any special configuration you can use /etc/default/celeryd as you config file. Just don't create /etc/default/celerybeat

Test it

You can check if the beat is active by:

sudo /etc/init.d/celerybeat start
sudo /etc/init.d/celerybeat status

Don't forget to stop the worker:

sudo /etc/init.d/celerybeat stop 

3. Maintenance

As it was show you can control worker and beat with the following commands:

/etc/init.d/celeryd {start|stop|restart}
/etc/init.d/celerybeat {start|stop|restart}

If you want to see the logs you can open CELERYD_LOG_FILE provided in /etc/default/celeryd. In our example is was /var/log/celery/worker1.log:

sudo nano /var/log/celery/worker1.log 

Additional - Flower Daemon

You may want to run Flower, and the following is the sample /etc/systemd/system/flower.service file :

[Unit]
Description=Flower Celery Service

[Service]
User=your_user
Group=www-data
WorkingDirectory=/var/www/project-working-directory
ExecStart=/home/user/miniconda3/envs/virtualenv/bin/flower --port=5555  --loglevel=info -A yourproject
Restart=on-failure
Type=simple

[Install]
WantedBy=multi-user.target