Run template step function and mock resource

[asyba]

Hi, this tool can help me doing this local test:
I want to test the step function logic, I have the template yml/json, can I use stepfuntions-local to execute that template locally?
And then replace the resource arn with local lambdas running? (the local lambda will only return some json info to test the InputPath and ResultPath of the step function logic).

[ChristopheBougere]

Hi @asyba, sorry for the delay.
Yep you should be able to do all of that with stepfunctions-local.
Here is an example with local lambdas on localstack, it should work the same with another local lambda server:
https://github.com/airware/stepfunctions-local/wiki/Lambdas-deployed-on-Localstack
Feel free to reopen if you encounter any error.

[asyba]

@ChristopheBougere One question about "stepfunctions-local does not aim to emulate Lambda. To do this you need a local Lambda server that is compliant to AWS API. We recommand to use localstack for that. See how to here."
Can I use "serverless offline" or "sam cli local" to have my lambda locally and with stepfunctions-local ? or only "localstack" can work?

[ChristopheBougere]

AFAIK, serverless-offline is a combination of Lambda and API Gateway and provides an HTTP endpoint which simulates the API Gateway endpoint.
But there is no local Lambda server (that you could run with aws lambda --endpoint http://localhost:{LAMBDA_PORT}) so I don't think it would work.
I would assume it is the same for AWS SAM local (the lambda engine is docker-lambda, which does not provide a lambda HTTP server), but this is to be confirmed.

[asyba]

Yes you are right, it seems that SAM is not supported (aws/aws-sam-cli#174) and also there is no way I think to connect "stepfunctions-local" with an ARN of a lambda that is running in SAM local..
I will have to learn to use localstack.

[ChristopheBougere]

Yep we made the choice when designing this package to only focus on the step functions layer and leveraging other packages for the lambda layer.
That way we can support every runtime and lambda feature natively (as long as they are supported by the lambda emulator).
Note that you can also deploy your lambdas on AWS, and run stepfunctions-local with these distant lambdas. But I guess it isn't what you are looking for.

[pianomansam]

I believe serverless offline now has support for invoking lambda functions with AWS SDK.