[bug]: Memory leak in Node requester

[aymeric-giraudet]

Description

We got reports of memory leaks from users of React InstantSearch with Next.js.

It's easy to reproduce, with an index.mjs file :

import process from 'process';

import { algoliasearch } from 'algoliasearch';

process.stdin.resume();

const client = algoliasearch('latency', '6be0576ff61c053d5f9a3225e2a90f76');

for (let i = 0; i < 1000; i++) {
  client.search({ requests: [{ indexName: 'instant_search' }] });
}

Then run node --inspect index.mjs, in Chrome open chrome://inspect and select index.mjs.

In the memory tab, the VM instance heap size hovers around 90MB without ever going down.

All responses are retained by the error handler.

I tried patching it by adding req.removeAllListeners() as well as response.removeAllListeners() in this end handler :

algoliasearch-client-javascript/packages/requester-node-http/src/createHttpRequester.ts

Lines 60 to 69 in 36ccbc9

	response.on('end', () => {
	clearTimeout(connectTimeout as NodeJS.Timeout);
	clearTimeout(responseTimeout as NodeJS.Timeout);
	resolve({
	status: response.statusCode || 0,
	content: Buffer.concat(contentBuffers).toString(),
	isTimedOut: false,
	});
	});

It's not perfect but it now settles around 20MB. Some unnecessary values are still there but maybe this will properly get GC'd if needed.

I told them to use requester-fetch instead as it's now supported by recent versions of Node.js. Maybe we could make that the default ? From my own benchmarks it seems better than the Node requester currently but with my proposed fix it would make the Node requester more performant than the fetch one 😅 (with undici)

Client

All

Version

5.15.0

Relevant log output

No response