Error when using Cloudformation package for Lambda functions?

If you’re like me, and you’ve been using Lambda, you would have been delighted when you found out that Cloudformation now had a transform for Lambda.

This post won’t get in much detail on how to implement a deployment using this Transform feature.. but instead, it will go through one of the issues I had when using it.

If you’re here, that’s because you’ve probably hit an issue that I had:

'NoneType' object has no attribute 'get'

What does that even mean !? Not a lot indeed ..

So I ran the aws cloudformation package command with the --debug flag, and this line stood out:

[...]
2017-04-16 18:28:12,761 - MainThread - botocore.args - DEBUG - The s3 config key is not a dictionary type, ignoring its value of: None
[...]

But really!? I interpreted this as the s3 bucket I specified to the package command does not exist .. but it does..

I’ve been using Cloudformation for a while and I’ve been relying a lot of aws cloudformation create-stack to validate my templates as I deploy them.. I just didn’t see a great value at using aws cloudformation validate-template up to now..

Yes, in a CI, it would be nice to separate the validation step from the deployment step, but really … I didn’t see much value as the create-stack or the update-stack would run the validation anyway!
I know .. I could have at least lint’ed my YAML but hey! I didn’t!

Well … now I found a good reason for it..

The issue was that my YAML was invalid! Of course!!

Guess what … I’ll be sure to at least lint my YAML now!!!