Work with Celery Tasks

D2S uses Celery for asynchronous background processing. This guide covers adding and modifying tasks.

Existing task modules

Task definitions are in backend/app/tasks/:

Module	Purpose
upload_tasks.py	File processing (COG conversion, point cloud processing, vector formats)
raw_image_processing_tasks.py	Raw image processing pipeline
stac_tasks.py	STAC catalog operations
toolbox_tasks.py	Analytics tools (NDVI, CHM, zonal statistics)
post_upload_tasks.py	Post-upload operations
admin_tasks.py	Administrative operations

Adding a new task

1. Define the task in the appropriate module (or create a new one in backend/app/tasks/):

   from app.core.celery_app import celery_app
   
   @celery_app.task
   def your_task(arg1, arg2):
       # Task logic here
       ...
   

2. Dispatch the task from an API endpoint or another task:

   from app.tasks.your_module import your_task
   
   your_task.delay(arg1, arg2)
   

Monitoring tasks

Task progress is tracked in the database and polled by the frontend. Long-running tasks update their status records so clients can display progress indicators.