A boilerpate development enviroment and reference implementation for AWS Lambda Node.js functions using the Serverless Framework
This is a development environment and reference implementation for an AWS Lambda Node.js 4.3 function. Features include:
- implement in modern Javascript (ES6);
- unit test with Mocha runner;
- static type check with flow;
- pre-commit Git hook with husky;
- deploy to AWS Lambda via the Serverless Framework;
- trigger by HTTP POST and/or S3 CreateObject Event;
- local unit tests and cloud integration tests;
- live tail CloudWatch logs at command line.
Note that in this Lambda reference implementation, Node.js is used. However, this environment and framework should work for other Lambda supported languages like Java or Python.
Getting Started
The Lambda Function is written in ES6 Node.js, and deployed via the Serverless Framework. The life-cycle (code linting, unit test, integration tests and various stage deployment) commands are wrapped as NPM scripts and can be easily be added to continuous integration/deployment framework like Jenkins.
In order to deploy and execute the functions in this module, you must have the relevant AWS previledges. See here for a full discussion.
To checkout and CD to the module:
git clone git@github.com:aidanbon/serverless-nodejs-archetype.git && cd serverless-nodejs-archetype && npm i
In the next section, we'll describe the various life-cycle commands.
Life-Cycle Commands
| Life-Cycle | Command | Description |
|---|---|---|
| development | npm run lint | perform syntax and type checking on the source code |
| testing | npm t | run local unit tests |
| deploymnet | npm run deploy | deploy to AWS Lambda in dev mode |
| deployment | npm run deploy:prod | deploy to AWS Lambda in production mode |
| deploymnet | npm run deploy:func | just re-deploy the function only, no infrastructure changes (faster) |
| testing | npm run test:invoke:http | launch integration test with a simulated HTTP event |
| testing | npm run test:invoke:s3 | launch integration test with a simulated S3 event |
| testing | npm run test:curl | launch integration test to hit the API endpoint via cURL |
| monitoring | npm run tail | tail the CloudWatch log for the Lambda function |
| clean up | npm run remove | to delete the AWS infrastructure created during deployment |
Tools and Tips
- Javascript code are written in ES2015, and store under the src folder.
- Code are transpiled by Babel to ES5 for Node v4.3 runtime in AWS Lambda. The transpiled code is stored at dist folder.
- Use standard.js for code style linting. (What is linting anyway?). Note: unit tests are excluded.
- Use flow for optional static type checking.
- Use husky to prevent bad commits.
- Use const, let, and avoid using var unless really needed. See discussion here.
- The entry point AWS Lambda function is handler.js.
- Unit tests (with the Mocha test runner and Chai assertion library) are located at test folder with -test.js suffix.