Can I simulate max_concurrency and batch_size params in event_source_mapping using aws_lambda_simple and sqs mocks?

[rishacha]

I have a scenario where I'm using an architecture like this -

1. I have a FIFO queue
2. I pushing objects to the FIFO queue
3. I have setup an event source mapping to aws_lambda
4. I want to test out the batch_size params, and max_concurrency params

How do I go about simulating/testing this scenario using a custom function and having it invoked multiple times with the event_source_mapping?

My idea is to use - aws_lambda_simple to do the job.

Would this work?

[bblommers]

Hi @rishacha! Moto isn't quite advanced enough to support your test case, I'm afraid. Invoking a function via an EventSource is done syncronously, so the batch_size will realistically always be 1. The MaximumConcurrency-argument isn't taken into account at all, for the same reason.

Maybe LocalStack may be a better fit? I don't know for sure whether they support it, but they tend to be better at emulating the real behaviour when it comes to AWSLambda Functions.