Custom resource deployment hangs forever about serverless

[Mmarzex]

Hi @mikybars your issue is a regression on our part in v4 I believe, so we will get a fix published shortly.

As for what you are seeing @sean-legitscript on v3 there haven't been any changes so not sure what could be causing that. Could you try adding the property provider.logs.frameworkLambda: true in your serverless.yml, then you should be able to see the logs in Cloudwatch for the custom resource lambda.

[Mmarzex]

@mikybars We updated v4 with a fix for this, if you want to run serverless update and try again?

[mikybars]

Yep, it seems to be working now. No more hangs. Good job ;)

[mikybars]

Thanks @sean-legitscript for reporting this as I was about to do the same thing 😅

In my case I have a PreSignUp hook set up for an existing (this fact is relevant) Cognito user pool and I was experiencing the same hangs that you describe.
After one week or so of painful debugging (1+ hour feedback loops) I can say that I finally figured it out and had it working. I don't want to bore anyone here with the gritty details but the problem lies within the custom-resources code provided by the serverless framework when you add the existing: true property in your config. This code, which is auto-generated as part of the package phase inside the .serverless folder, is responsible for provisioning custom resources in AWS. As I had the opportunity to find out this code is wrong:

export default {
  handler: handlerWrapper(handler, 'CustomResourceExistingCognitoUserPool')
};

As far as I'm concerned (I'm not a JS guy) ES6 modules are not supported in Node.js environments, which use CommonJS syntax instead:

module.exports = {
  handler: handlerWrapper(handler, 'CustomResourceExistingCognitoUserPool')
};

Btw, this would have been way easier to find out should the lambda function responsible for provisioning the custom resource had had a log group set up in CloudWatch in the first place. I guess anyone expected this to ever fail 🤷🏾

I can offer myself to fix this, btw 🙂