Getting Started

This repo was created to easily reproduce a bug introduced in [email protected].

To begin, clone this repo and install dependencies:

$ npm install

Then build the project (this script will run cdk synth --no-staging and will pipe the output into template.yaml):

$ npm run build

Now try running the lambda locally using sam local invoke (to install sam please refer to the AWS docs):

$ sam local invoke "funcC3A0C2E2"

Note: You may need to change the name of the lambda. To find the name, look in the template.yaml file created by cdk synth.

You should see an error like this:

{"errorType":"Runtime.HandlerNotFound","errorMessage":"index.handler is undefined or not exported"}

To see this working correctly, modify package.json to change all *aws-cdk* packages from version 1.61.0 to 1.60.0. Then repeat the steps above starting with npm install. Instead of seeing an error you should see a successful response from the lambda:

{"statusCode":200,"headers":{},"body":"Hello!"}

Details

Notice that when running sam with the broken version there is a line that looks like:

Mounting /Users/lprice/work/playground/demo-aws-cdk-asset-path-bug/asset.eaa6b4d3a12be11c844440afe5ee48ce3999505afaa441be0292009b5f7f2766 as /var/task:ro,delegated inside runtime container

This is SAM trying to mount the lambda code to the Docker container from which the lambda will be invoked. This path does not actually contain the bundled lambda code, which is why we see the error.

Compare that with the corresponding line from the working version:

Mounting /Users/lprice/work/playground/demo-aws-cdk-asset-path-bug/.cdk.staging/asset-bundle-2VIsWk as /var/task:ro,delegated inside runtime container

This path does contain the lambda code, so the sam local invoke succeeds.

These paths ultimately come from the template that cdk synth --no-staging creates. Notice the aws:asset:path under the lambda's Metadata property.