How do the functions 'task' and 'shared_task' differ in the context of task processing libraries in Python?

task is bound to a specific application instance or task broker (for example, in Django settings). shared_task is independent and can be used from any part of the project without explicit binding to an application.

Main differences:

• Application binding:
  • task: Defined in the context of a specific application or broker. Requires importing the application instance.
  • shared_task: Not bound to a specific application. Available through import from celery.
• Usage:
  • task: Usually used within a specific project where the Celery application is defined.
  • shared_task: Recommended for reusable tasks that can be called from different projects or independent scripts.
• Import:
  • task:

    // tasks.py
    from myapp.celery import app
    
    @app.task
    def my_app_task():
        pass
    

  • shared_task:

    // my_tasks.py
    from celery import shared_task
    
    @shared_task
    def general_task():
        pass
    

Choosing between task and shared_task depends on the use case. For most tasks within a single project, task is suitable. For common, reusable tasks, shared_task is preferable.