Email Notification System

[Ramez Kabbani]

I'm trying to build an email notification system, and would appreciate some guidance.

Triggers:

1. New item created & user assigned to instance
2. Existing item edited & user assigned to instance
3. Comment added to object where user is involved
   
4. Item date field expires & user opts in to this notification type & user part of item's project

My thoughts:

• I can use the post_save signal to trigger a Celery task that sends the email.
• I would need to create a decorator to register models to be monitored
  
• I could create a separate notification app so I can build a setting interface that exposes criteria like which projects get monitored.
• For trigger #2 I can create a celery task that runs at, say, 9am everyday and checks all instances for expired date. It would send an email if the condition is True
  

This is as much as I have figured out. I need to work on implementation now, but would like some feedback.