README.md

AWS CDK LLRT Function construct

This is a CDK construct library that aims to accelerate your experiment on LLRT, a lightweight JavaScript runtime for AWS Lambda.

Usage

Install it via npm:

npm install cdk-lambda-llrt

Then you can use LlrtFunction construct. Just set an entry point for the function.

import { LlrtFunction } from 'cdk-lambda-llrt';

const handler = new LlrtFunction(this, 'Handler', {
    entry: 'lambda/index.ts',
});

If you are already using NodejsFunction construct, you should be able to just replace it to LlrtFunction.

Warning

LLRT is currently experimental and not fully compatible with Node.js. You should expect some trial and errors to use LLRT with your existing code.

If you want to upgrade the LLRT version, remove the .tmp directory, which contains the cache of LLRT binary fetched from GitHub (only applicable when you set llrtVersion to latest (default)).

Setting platform=browser

In some cases, your code may run successfully on LLRT by setting bundle target platform to browser. You can configure it by the following code:

import { LlrtFunction } from 'cdk-lambda-llrt';

const handler = new LlrtFunction(this, 'Handler', {
    entry: 'lambda/index.ts',
    bundling: {
        esbuildArgs: { '--platform': 'browser' },
    }
});

Docker bundling

In some environments, LlrtFunction's bundling steps will fail because the underlying NodejsFunction sometimes runs the commands on your host machine, and your environment does not support these commands or syntax. To avoid this error, you can force docker bundling for these commands not to depend on your execution environment.

new LlrtFunction(this, 'Handler', {
    entry: 'handler.ts',
    bundling: {
        forceDockerBundling: true,  // Add this!
    },
});

Note that we enable this flag automatically on Windows platform.

LLRT Binary Types

LLRT publishes several types of binaries with different sets of bundled SDKs:

• LlrtBinaryType.FULL_SDK: Includes all AWS SDKs
• LlrtBinaryType.NO_SDK: No AWS SDKs included
• LlrtBinaryType.STANDARD: Standard bundle (default)

You can specify the binary type when creating a new LlrtFunction:

const handler = new LlrtFunction(this, 'Handler', {
    entry: 'lambda/index.ts',
    llrtBinaryType: LlrtBinaryType.FULL_SDK,
});

Examples

See example for examples to use LlrtFunction construct.