Comment by andyferris

1 month ago

In the apps I've written, generally the user interaction with the API is synchronous and has some immediate effect (e.g. uploading a file - the file is committed and guaranteed accessible by the time the HTTP success response is sent, giving the system strong causal consistency) and within that same transaction I enqueue the related background task (e.g. processing the file) so that we never get an uploaded file with no associated background task (or vice-versa).

(The background task may involve its own transactions when dequeued later, and spawn further background tasks, etc)

1 comment

andyferris

KraftyOne 1 month ago

Got it! So you can make the entire HTTP endpoint a DBOS workflow that performs the synchronous work then launches a background task. Something like this:

    @app.get("/endpoint")
    @DBOS.workflow()
    def http_workflow():
        synchronous_task() # Run the synchronous task
        DBOS.start_workflow(background_task) # Start the background task asynchronously

This is atomic in the sense that if the synchronous task runs, the background task will always also run.