Differences between invoke, offline, lambda console, api gateway and which to use?


#1

Hello, I have been chasing what I thought was a bug in my code but turns out to be a difference in the way the event is handled depending on environment.

In my development flow I use sls invoke local for quick checks and the sls offline plugin with PostMan for more detailed debugging. Then I deploy to AWS and use sls invoke for another quick check and PostMan to
confirm the API Gateway endpoint is functioning as expected.

As soon as I introduce parameters in the form of an event everything goes haywire. It seems that some cases parameters are on the event and in other cases event.body after JSON.parsing it. I have documented each case and it’s results in https://docs.google.com/spreadsheets/d/1QJOak5XlZuX0-ETHTbpV4ScFvp2uvsIwQl7IvmHhH_g/edit?usp=sharing.

Can anyone enlighten me:

  1. Is this normal behaviour?
  2. If so, why?
  3. What is the established best practice for managing it? Should I use environment variables, attempt to JSON parse and act on success/fail, something else?

For now I have simply added let params = (event.body) ? JSON.parse(event.body) : event; as the first line inside each handler function and it seems to be working. But I lost a lot of time getting to this stage.