Memory leak with hono, @hono/node-server, @hono/graphql-server

[kyscott18]

It seems like there is a memory leak when using hono, @hono/node-server, and @hono/graphql-server together.

Minimal reproduction mostly from the example in @hono/graphql-server:

import { Hono } from "hono";
import { serve } from "@hono/node-server";
import { graphqlServer } from "@hono/graphql-server";
import { buildSchema } from "graphql";

setInterval(() => {
  const before = process.memoryUsage().heapUsed / 1024 / 1024;
  global.gc?.();
  const after = process.memoryUsage().heapUsed / 1024 / 1024;
  console.log({ before: before.toFixed(2), after: after.toFixed(2) });
}, 1_000);

export const app = new Hono();

const schema = buildSchema(`
type Query {
  hello: String
}
`);

const rootResolver = (ctx) => {
  return {
    hello: () => "Hello Hono!",
  };
};

app.use(
  "/graphql",
  graphqlServer({
    schema,
    rootResolver,
  })
);

serve(app);

Result of running the server and then sending requests with autocannon after a few seconds:

autocannon -c 100 -d 10 -m POST -H "Content-Type: application/json" -b '{"query":"{ hello }"}' http://localhost:3000/graphql

(base) kylescott@Kyles-MacBook-Pro-2 hono-node-repro % node --expose-gc index.js
{ before: '8.86', after: '6.72' }
{ before: '6.83', after: '6.75' }
{ before: '6.77', after: '6.75' }
{ before: '6.77', after: '6.75' }
{ before: '6.82', after: '6.76' }
{ before: '6.78', after: '6.76' }
{ before: '6.83', after: '6.77' }
{ before: '55.64', after: '37.63' }
{ before: '153.87', after: '97.79' }
{ before: '205.73', after: '152.70' }
{ before: '262.65', after: '208.79' }
{ before: '310.95', after: '259.03' }
{ before: '355.99', after: '308.32' }
{ before: '400.77', after: '354.94' }
{ before: '444.92', after: '398.86' }
{ before: '489.06', after: '443.80' }
{ before: '523.01', after: '484.06' }
{ before: '565.09', after: '523.40' }

https://github.com/kyscott18/hono-node-mem-leak