Lambda DevKit

A development toolkit for compiling and running AWS Lambda functions locally with API Gateway simulation.

---

Features

• Local Execution: Run your AWS Lambda functions locally without deploying to AWS.
• API Gateway Simulation: Simulate API Gateway routes and methods (e.g., GET, POST, PUT, DELETE).
• Compilation Support: Automatically compile TypeScript or JavaScript Lambda functions.
• Flexible Configuration: Define routes, handlers, and environment variables in a simple configuration file.
• Developer-Friendly CLI: Use the ldk command to manage and test your Lambda functions.

---

Installation

Install the package as a project dependency:

pnpm add @nexckycort/lambda-devkit -D

---

Quick Start

1. Create a Configuration File
   Create a file named lambda-devkit.config.ts in the root of your project. Here's an example configuration:

import type { LambdaDevkitConfig } from '@nexckycort/lambda-devkit';

const config: LambdaDevkitConfig = {
  server: {
    routes: [
      {
        method: 'GET',
        path: 'users',
        lambda: {
          handler: 'functions/getUsers',
          timeout: 5000,
        },
      },
      {
        method: 'POST',
        path: 'users',
        lambda: {
          handler: 'functions/createUser',
          timeout: 10000,
        },
      },
    ],
    port: 4000,
    environment: {
      ENV: 'dev',
    },
  },
  build: {
    bundle: true,
    minify: true,
    external: ['@aws-sdk/*'],
  },
};

export default config;

2. Start the Local Server
   Run the following command to start the local server:

   ldk dev

3. Test Your Endpoints
   Use tools like Postman or curl to test your endpoints:

   curl http://localhost:4000/users

---

Usage

Commands

The ldk CLI provides the following commands:

Command	Description
ldk dev	Start the local server with API Gateway simulation.
ldk build	Compile your Lambda functions.

Example

Here’s an example of how to use the CLI:

# Build your Lambda functions
ldk build

# Start the local server
ldk dev

---

Configuration

Lambda DevKit uses a configuration file (lambda-devkit.config.ts) to define routes, handlers, and other settings. Below is a detailed explanation of each field:

server

Server configuration for local development.

Field	Type	Description
routes	RouteConfig[]	List of routes and their configurations.
port	number	Port on which the local server will run. Default: 4000.
environment	object	Environment variables to be passed to the Lambda function.

routes

An array of route configurations. Each route maps an HTTP method and path to a Lambda function.

Field	Type	Description
method	string	HTTP method (e.g., GET, POST, PUT, DELETE).
path	string	Path for the route. Supports wildcards like users/*.
lambda	LambdaConfig	Configuration for the Lambda function that handles requests to this route.

lambda

Configuration for a Lambda function.

Field	Type	Description
handler	string	Path to the folder containing the Lambda handler (e.g., functions/myFunction).
timeout	number	Maximum execution time for the Lambda function in milliseconds.

build

Build configuration for the Lambda functions.

Field	Type	Description
entryPoint	string	Entry point for the build process. Default: "functions/**".
bundle	boolean	Whether to bundle the Lambda function code into a single file.
minify	boolean	Whether to minify the Lambda function code during the build process.
sourcemap	boolean | string	Sourcemap generation options (true, 'linked', 'inline', etc.).
outbase	string	Base directory for resolving entry points. Default: "functions".
external	string[]	External libraries that should be excluded from the build. Default: ["@aws-sdk/*"].

---

Examples

Basic Example

Here’s a simple example of a Lambda function and its configuration:

src/getUsers/index.ts

export const handler = async (event: any) => {
  console.log("Event:", event);

  return {
    statusCode: 200,
    body: JSON.stringify([
      { id: 1, name: "Alice" },
      { id: 2, name: "Bob" },
    ]),
  };
};

lambda-devkit.config.ts

import type { LambdaDevkitConfig } from '@nexckycort/lambda-devkit';

const config: LambdaDevkitConfig = {
  server: {
    routes: [
      {
        method: 'GET',
        path: 'users',
        lambda: {
          handler: 'functions/getUsers'
        },
      },
    ],
    port: 4000,
  },
  build: {
    bundle: true,
    minify: true,
    external: ['@aws-sdk/*'],
  },
};

export default config;

Run the server:

ldk dev

Test the endpoint:

curl http://localhost:4000/users

---

License

This project is licensed under the MIT License. See the LICENSE file for details.