This is used for integration testing and bundling purposes.

Integration Testing

A simple CDK template uses the Dockerfile to bundle a layer containing tesseract.

Using npx cdk synth the CDK app is synthesized. The artifacts are bundled as this happens. The output artifacts of the synth command (i.e. cloudformation template, layer, testing lambda) is put into cdk.out by the CDK.

AWS SAM CLI is used to invoke a testing function locally using the respective runtime and layer. The result is checked for errors.

Commands to reproduce:

npm ci
npx cdk --app 'npx ts-node index.ts' synth
## run integration test using Python 3.10
npx npm run test:integration:python
## run integration test using NodeJs 18
npx npm run test:integration:node

Bundling

After npx cdk synth was executed bundles of the binary can be created with npm run bundle:binary. The bundles will be put into the ready-to-use folder.