Lambda Web FunctionsでHonoの実用パターンと設定の境界を検証する

import { createServer } from "node:http";
import { getRequestListener } from "@hono/node-server";

const address = process.env.AWS_LAMBDA_HTTP_ENDPOINT;
if (!address || !/^[A-Za-z0-9.:[\]-]+:\d{1,5}$/.test(address)) {
  throw new Error("AWS_LAMBDA_HTTP_ENDPOINT must contain a host and port");
}
const endpoint = new URL(`http://${address}`);
const hostname = endpoint.hostname.replace(/^\[|\]$/g, "");
const port = Number(endpoint.port);
if (!hostname || !Number.isInteger(port) || port < 1 || port > 65535) {
  throw new Error("invalid AWS_LAMBDA_HTTP_ENDPOINT");
}
const server = createServer(getRequestListener(app.fetch));
server.listen(port, hostname);

// WebFunctionRevision の ServiceConfig 内
TimeoutSeconds: 3,
MaxConcurrencyPerEnvironment: 8,
EnvironmentVariables: {
  AWS_LAMBDA_NODEJS_ENTRYPOINT: "server.mjs",
  LAB_REVISION_MARKER: "base",
},

// WebFunctionEndpoint の properties 内
EndpointType: "HomeRegion",
AuthType: "IamAuth",
ScalingConfig: { MaxEnvironments: 2 },
ThrottleConfig: { RateLimit: 100 },

app.post(
  "/body-limit",
  bodyLimit({
    maxSize: 1024,
    onError: (c) => c.json({ error: "body too large" }, 413),
  }),
  async (c) => {
    const bytes = new Uint8Array(await c.req.arrayBuffer());
    return c.json({ bytes: bytes.byteLength, sha256: digest(bytes) });
  },
);

// 各chunkの送信
await stream.writeSSE({ event: "chunk", id: String(index), data: String(index) });
// 指定件数の送信が終わった場合だけ送信
await stream.writeSSE({ event: "done", data: "complete" });