Setting up websockets in AWS Lambda

[muezz]

I am working on an API where I need to have a websocket route. Since I need to deploy on AWS Lambda, I am looking to find the right way to set it up.

To run things locally for development, I use the node runtime. I have three main files:

// apps/backend/lambda/app.ts
import { Hono } from "hono/quick";
const app = new Hono<MaybeAuthenticatedApiContext>().basePath("/api");
app.route("/auth", authRoutes);
export default app;

// apps/backend/lambda/index.ts
import { serve } from "@hono/node-server";
serve(
  {
    fetch: app.fetch,
    port: 3000,
  },
  (info) => {
    console.log(`Server is running on http://localhost:${info.port}`);
  }
);

// apps/backend/lambda/handler.ts
import { handle } from "hono/aws-lambda";
import app, from "./app";
export const handler = handle(app);

As you can see, app.ts holds the server logic, index.ts allows me to run the server locally and I use handler.ts for deployment on lambda via cdk.

Here is where I am struggling:

// apps/backend/lambda/app.ts
import { Hono } from "hono/quick";
import { createNodeWebSocket } from "@hono/node-ws";
const app = new Hono<MaybeAuthenticatedApiContext>().basePath("/api");
const { injectWebSocket, upgradeWebSocket } = createNodeWebSocket({ app });
app.route("/auth", authRoutes);
app.get(
  "/ws",
  upgradeWebSocket((c) => ({
    // logic for websockets goes here
  }))
);
export default app;

I am struggling here as createNodeWebSocket comes from @hono/node-ws but app.ts needs to be runtime agnostic so it can be used in node for local dev on in AWS Lambda for production. I am also not sure how, where or when to call injectWebSocket.

If I am thinking about this completely incorrectly, please let me know.