nodejs-lambda-serverless-boilerplate

Boilerplate to create AWS Lambda Function with Node.js and deploy it with Serverless

Boilerplate for Node.js lambda function, including Serveless configuration, JavaScript function, and unit test examples.

This example lambda function make a get request to external api endpoint and return the result through the API gateway endpoint. The function runs in the default VPC.

What can I do with this boilerplate

Create Node.js lambda function with unit & integration tests (using mocha).
Testing code coverage report (using istanbul).
Deployment with Serverless command into different environments.
Serverless configuration includes:
1. Create API gateway with custom endpoint.
2. Run Lambda function in a specific VPC and a group of subnets.
3. Assign IAM Roles to the function.
4. Create AWS resources that are associated with the function.

(1) Serverless installation

Using serverless framework to package & deploy lambda function. Install serverless globally as below.

npm install serverless -g

(2) Package installation

Run the command below to install all the packages

npm i

(3) Deployment

Deployment can be done through the local machine by running Serverless command. For production, it is recommended to use a CD/CI tool such as Jenkins. AWS CLI must be configured with the appropriate credental (Configureing the AWS CLI).

sls deploy --stage dev

(4) Unit testing and code coverage

Using Mocha for both unit and integration tests. Istanbul for test coverage.

Unit tests are for checking individual functions without external dependencies. Integration tests are running on the actual endpoint.

Unit test

npm test

Integration test

npm run-script integration

(5) Calling endpoint

The endpoint will be output in Jenkins console after deployment completes. It is a simple get request. You can call it with curl or web browser.

Endpoint looks like: https://somekindofuniqueidyouget.execute-api.ap-southeast-2.amazonaws.com/dev/nodejs-lambda-boilerplate

Upon deployment check for the deployment message as below.

Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service .zip file to S3 (10.87 MB)...
Serverless: Validating template...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
.............................
Serverless: Stack create finished...
Service Information
service: nodejs-lambda-boilerplate
stage: dev
region: ap-southeast-2
stack: nodejs-lambda-boilerplate-dev
api keys:
  None
endpoints:
  GET - https://somekindofuniqueidyouget.execute-api.ap-southeast-2.amazonaws.com/dev/nodejs-lambda-boilerplate
functions:
  nodejsLambdaBoilerPlate: nodejs-lambda-boilerplate-dev-nodejsLambdaBoilerPlate

How did the boilerplate get created?

This section explains how the boilerplate was created.

Initialise with npm init

npm init -y

Create a new AWS lambda service using the Node.js template. This create a boilerplate with .gitignore, handler.js and serverless.yml files.

serverless create --template aws-nodejs --path serverless

Create folders and files

  - config
    - certs.yml (Certificate names per environment)
    - domains.yml (Domain names and base path for API endpoint. The record will be created by Route53)
    - env.yml (Environment variables set in the lambda execution environememt. Example includes environment and parameter names for db connections)
    - permissions.yml (Defines what lambda function is permitted to do. Example includes access rights to parameter store)
    - resources.yml (Resources you want to create along with lambda function. Example includes alerts.)
    - vpc
      - dev.yml (Including Security group ids and subnet ids where you want to run the lamda function.)
      - tst.yml
      - prod.yml
  - src
    - handler.js
    - dataProcessor.js
    - exampleData.js
  - test
    - handler.spec.js
    - dataProcessor.spec.js

Installing dependencies as in package.json

npm install

graileanu / nodejs-lambda-serverless-boilerplate