Lambda Template

This repo contains opinionated boilerplate code for building and bundling multiple lambdas from a single src directory, without needing to nest multiple build files. Esbuild is used to minify and optimize the lambda bundle to reduce cold starts and optimize runtimes. There are also examples deploying these lambdas via cdk and serverless

Folder Structure

src
├── common
│   └── logger.ts
├── products
|   └── handler.ts
└── users
    └── handler.ts

Each directory inside the src directory gets bundled as its own lambda, except the common directory. There are 2 lambda assets, a users.zip and a products.zip. The common directory is an exception which does not get bundled as its own asset. It has code that gets reused across the lambdas.

Building

To build the lambdas inside this repository, you can just run npm run build

This will create a dist directory with the following structure

dist
├── products
│   ├── handler.js
│   ├── handler.js.map
│   └── products.zip
└── users
    ├── handler.js
    ├── handler.js.map
    └── users.zip

This *.zip files can be uploaded as lambda assets through cdk, serverless, cloud formation... to a lambda with entrypoints handler.handler

Adding new lambdas

To add a new lambda, a new folder under the src directory needs to be created, with a file handler.ts. This handler.ts file needs to export a export const handler = () => {} function which will be used as the lambda entry point. This file will then get bundled by esbuild as a lambda asset.

Shared code

Any code that needs to be shared across multiple lambdas can go into the common folder. This folder is unique in the sense that it is the older folder directly under src that does not get builded into its own lambda.

Deploying

First run npm i to install all required dependencies.

To deploy the example lambdas via cdk run AWS_PROFILE=<profile> npm run cdk-deploy. To deploy via the serverless framework run AWS_PROFILE=<profile> npm run serverless-deploy.