How to determine that a job has completed using Azure functions

Question

I am working on a project that has the following setup.

• A timed function starts the whole process.
• This function puts a set of messages on a queue. One for each subtask to be executed.
• Each subtask function then puts a set of messages on a different queue for all the sub-subtask that should be executed.

One run of the process would generate roughly 100000 function calls in total.

I would like to know when the whole process is complete so that I can do some post processing. What would be the best way to achieve this?

I can think of two ways:

• Timed function that checks for status. This works, but as you pay per function call it would be wasting a lot of calls.
• Each function calls a Completed function, which does some processing if it has been called enough times or some condition in a database is reached. Again, as you pay per function call it would be wasting a lot of calls.

Any better ideas?

Answer 1

Durable functions would be worth looking into. The way they work is you have one function run which orchestrates the processing of normal functions. The durable function maintains it's state for the duration of all the sub-functions. So after all of your sub-functions complete you can call a single completed function.

See https://learn.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-overview