This app includes only one NPM package located in the dependencies/nodejs/package.json file for jsonwebtoken to illustrate the use of a node package in a layer (you may add more).
The app also includes a shared file, in this case a helper file, named helper.js also in the dependencies/nodejs folder. When the app is run, NPM packages are referenced from the dependiences/node_modules folder and the shared file is also referenced.
The main file extend/index.js is included inside of a folder to illustrate structuring code which creates smaller functions in AWS Lambda.
To run this app locally, run the following commands:
cd dependencies/nodejs
npm install
cd ../../
sam local start-api --port 3030
The app will be running at http://localhost:3030/
To stop the app, run Control+C on a Mac.
Use the below commands to deploy to AWS. The first command packages the contents of this app into a .zip file and uploads that .zip file to AWS S3 (required to deploy to AWS Lambda). Replace [YOUR_BUCKET] with the name of your AWS S3 bucket name (you may wish to create a new bucket for this app). Note, you have to have programmatic access to AWS to run the below commands (search aws configure for more info)
aws cloudformation package --template-file template.yaml --s3-bucket [YOUR_BUCKET] --output-template-file outputtemplate.yaml
The next command deploys the code to Api Gateway and Lambda from the uploaded .zip file in the previous step. Replace [YOUR_STACK_NAME] with a stack name of your choosing if you don't already have one (I used sam-layers-sample).
aws cloudformation deploy --stack-name [YOUR_STACK_NAME] --template-file outputtemplate.yaml --capabilities CAPABILITY_NAMED_IAM