lambda-node-runtime

Lambda Node Runtime

The module allows you to run your JavaScript code on any Node.js version in AWS Lambda.

AWS Lambda rarely updates Node.js version, in fact AWS Lambda Node.js version problem looks similar to one Babel tries to solve for JS versions. This module enables you to use latest Node.js version with latest features and bug/security fixes.

Quick start

Installation

Add module to your AWS Lambda Node.js project:

npm install lambda-node-runtime -S

Usage

Write a module that holds AWS Lambda handler:

module.exports.handler = async (event, context) => {
    // Your code
}

Reference your handler using AWS Lambda Environment Variable

LAMBDA_NODE_HANDLER=index.handler

Set AWS Lambda Handler to expression

node_modules/lambda-node-runtime/index.handler

Optionally set desired Node.js version in package.json (default version is 8.10.0)

{
    ...
    "lambda-node-runtime": {
        "node-version": "8.10.0"
    }
    ...
}

How it works

When you install lambda-node-runtime module it downloads Node to node_modules/lambda-node-runtime/.node dir. Therefore, when you create an AWS Lambda package it includes desired Node runtime. When AWS Lambda package is deployed and invoked, bundled Node child process starts and executes your JS code.

Why is this possible?

It is possible to run Node version of your desire because Node binary is relatively small (around 10 MB when zipped) so there is plenty of space left for code (AWS Lambda package size restriction is 50 MB).

Also Node is fast to start so the latency between when you invoke AWS Lambda function and when it actually starts running the code is lower.

Please note that latency is there because new Node.js child process must be started. However, Node.js child process is reused in hot AWS Lambda function meaning only cold start is slower.

More details (comparisons, benchmarks) will be provided after the module is used for a number of projects.