So, AWS Lambda Web Functions just came out, and I'm super excited about them.

What are they? Well, you can now ship Express, Hono, or React Router with no Lambda-specific adapters or wrappers.

Let me show you how I got this demo set up with CDK.

λ: https://cxrj1w1j65n0k7ss.p7v.lambda-web.us-east-2.on.aws (this may not live forever but the code should)

⚠️ DISCLAIMER: The code we are about to see is written with L1 CDK constructs. The L2 constructs are being tracked via this PR.

First, let's look at the server code I have in Express. I've omitted the bulk of its logic for brevity.

Here, you can see that it's an Express.js server binding to a port.

import express from "express"; const [hostname, rawPort] = ( process.env.AWS_LAMBDA_HTTP_ENDPOINT ?? `127.0.0.1:${process.env.PORT ?? "3000"}` ).split(":"); const port = Number(rawPort); export const app = express(); export const server = app.listen(port, hostname, () => { console.log(`Spinning Lambda is listening on http://${hostname}:${port}`); });

I can run the code locally with pnpm dev.

Now, let's look at the CDK stack used to deploy this function.

export class SpinningLambdaStack extends Stack { constructor(scope: Construct, id: string, props?: StackProps) { super(scope, id, props); // code bucket stuff omitted const webFunction = new CfnWebFunction(this, "WebFunction", { functionName: `${this.stackName}-web`, // many props omitted for brevity }); const revision = new CfnWebFunctionRevision(this, "WebFunctionRevision", { functionName: webFunction.ref, // many props omitted for brevity }); const endpoint = new CfnWebFunctionEndpoint(this, "WebFunctionEndpoint", { functionName: webFunction.ref, // many props omitted for brevity }); } }

Now for deployment. I'm using the new AWS experience, so I have a project dedicated to this demo.

I grab some credentials for my account with aws login. I need to do a one-time setup to bootstrap CDK with npx cdk bootstrap.

Once that's done, I can run pnpm deploy to ship it.

Then it's live 🚀!

Share this on X/Twitter, and it should render as an embed:

https://cxrj1w1j65n0k7ss.p7v.lambda-web.us-east-2.on.aws/embed

Full repo:
https://github.com/sboult/lwf-three-js

As always, happy coding 😉!

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Sean BoultFollow

Developer. Hacker. Creator.