Input not passed to Lambda functions

Love the idea behind this project and have been trying to incorporate it into one of my apps that uses step functions so I can test 100% locally. I’ve been able to:

1. Create step function state machines locally.
2. Execute the state machine, passing some JSON as input.
3. When the state machine hits a Task with a Lambda function, I’ve been able to use --lambda-endpoint option to have it call a mock lambda server I’m running locally.

The gotcha is that my mock lambda server gets the POST… But the body contains an empty JSON input: {}. For some reason, the original JSON input I passed in is dropped. Any ideas what I’m doing wrong?

[brikis98]

Scratch that, I was wrong. stepfunctions-local sends the input along just fine. The problem is AWS itself plus the web framework I was using with Node. In particular:

1. AWS does not set a Content-Type header when it invokes a Lambda function.
2. My Node.js web framework, for some reason, doesn’t read in the request body when Content-Type is not set, and, confusingly, just gives you an empty {} body instead.

[marlonbernardes]

Exactly my issue - thanks for sharing the root cause here, @brikis98. It would have taken me much longer to figure this out if not for your comment!