# 1. First install celery
# pip install celery

# --------------------------

# Inside main project directory, create celery.py file

# celery.py
import os
from celery import Celery
from django.conf import settings

# set the default Django settings module for the 'celery' program.
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'ProjectName.settings')
app = Celery('ProjectName')

# Using a string here means the worker will not have to
# pickle the object when using Windows.
app.config_from_object('django.conf:settings')
app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)

# --------------------------
# in settings.py

BROKER_URL = 'redis://127.0.0.1:6379'
CELERY_RESULT_BACKEND = 'redis://127.0.0.1:6379'
CELERY_ACCEPT_CONTENT = ['application/json']
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_ENABLE_UTC = False
CELERY_TIMEZONE = 'MST'

# --------------------------
# create python package called tasks and store all your long running tasks as module here

# email_sender_tasks.py
from celery import shared_task

@shared_task
def send_notification_email(data, email):
	# your logic here
    try:
		msg_html = render_to_string('templates/email_template.html',{})
        send_mail('Welcome!', msg_html, email,
                  [data['email']], html_message=msg_html)
    except Exception as error:
        return error

# ------------------
# Now call the task from your view

from email_sender_tasks import send_notification_email

def register(request):
	# your logic here
	if register_status == True:
		send_notification_email.delay({"user_info": request.user}, email='insight@gmail.com')

# -------------------
# Start celery server in your local machine
celery -A ProjectName worker -l info

# *******************************************
# in the EC2 instance, you need to configure the EC2 for celery and django
# the supervisor configuration: celery_supervisor.conf
[program:project_celery_conf]
command = /var/www/start_celery.sh           ; Command to start app
user = www-data                                            ; User to run as
stdout_logfile = /var/www/logs/celery.log     ; Where to write log messages
redirect_stderr = true                                     ; Save stderr in the same log
environment=LANG=en_US.UTF-8,LC_ALL=en_US.UTF-8            ; Set UTF-8 as default encoding

# start_celery.sh

#!/usr/bin/env bash

NAME="project_celery_conf"                          # name of the application
PROJECT_DIR=/var/www/proj-name               # project directory
APP_DIR=/var/www/proj-name                           # can be project dir
APP_MODULE=ProjectName                         # application module name

echo "Starting $NAME as `whoami`"


# Activate the virtual environment
source $PROJECT_DIR/venvpp/bin/activate
export PYTHONPATH=$APP_DIR:$PYTHONPATH

cd $APP_DIR

# Start Celery
exec celery -A ${APP_MODULE} worker -l info