axios vs undici with ProxyAgent

[yerlantemir]

Hi team,

First of all, thank you for amazing work than you have done so far! I hope this bug is happening because of my misuse and would love to contribute if there are some problems with the library.

Bug Description

When using undici with ProxyAgent, request performance is significantly slower compared to axios with https-proxy-agent for parallel requests through a proxy server.

Reproducible By

1. Setup proxy server
2. Send 1000 requests to the 3rd party service parallelly using axios and undici with ProxyAgent
3. Compare the results

Expected Behavior

Replacing axios with undici should maintain or improve performance.

Logs & Screenshots

-------------------
`Results for axios: {
  Concurrency: 10,
  'Avg Duration': '465ms',
  'Total Time': '111s'
}
-------------------
Results for undici: {
  Concurrency: 10,
  'Avg Duration': '604ms',
  'Total Time': '145s'
}

You can find the test script here: https://jumpshare.com/v/0ol3h5KZePayCSY46GY1?b=DJylk9UBBfNgJiz93jg4

Environment

MacOs Sonoma 14.3
node v20.13.0

Additional context

We are running a service that sends ~1000s of requests each minute to the third party service through proxy server. Currently, we are using axios with https-proxy-agent and are exploring undici for potential performance improvements and the ability to add retry logic. Could you please help identify what might be causing this issue? Is there a specific way undici should be configured in this case, or could this be related to a bottleneck in the library?

[mcollina]

I don't think the proxy agent was every optimized, thanks for the call. Can you help assembling a benchmark everyone can reproduce? Otherwise it would be really hard to optimize.

---

Note that your undici call has a significant memory leak. You are not consuming the body, preventing the sockets to be reused. You should try:

    const proxyAgent = getProxyAgentFromUndiciPool();
    const response = await request(URL, {
      dispatcher: proxyAgent,
      method: 'POST',
      blocking: true,
      upgrade: false,
      reset: false,
      body: JSON.stringify(BODY),
      headers: HEADERS,
      throwOnError: true
    });
    await response.body.dump() // or response.dump().catch(() => {})
    const { statusCode } = response;

[yerlantemir]

@mcollina thanks for quick response! I created a reproducible environment for this issue, you can find a code here: yerlantemir@9820786.

With the following setup, I am constantly getting worse results with undici

Would love to hear your thoughts on this

[PandaWorker]

you have an error with axios in the last example, because of this, it sends requests through the default agent, and not the one specified

you also have a restriction on agent connections, but requests are still sent one at a time and not immediately to all possible connections

const makeAxiosRequest = async () => {
  await axios.get(serverUrl + '/hello?foo=bar', {
    httpsAgent: axiosHttpsProxyAgent,
    httpAgent: axiosHttpsProxyAgent // +++
  });
}

Results for 10000 requests
axios 2461 ms
undici 2456 ms

[PandaWorker]

If you use all 100 agent connections, then undici will be 2 times faster

[PandaWorker]

Try this

https://gist.github.com/PandaWorker/8b95c10f156f4bbc997555d0a1505cab

[mcollina]

Thanks @PandaWorker!

[yerlantemir]

@PandaWorker Thanks for your help. I couldn't make 2x faster, but at least it's not losing to axios on performance.

On the production environment, axios is still a little bit faster(10-20%). Currently I am trying to replicate this environment and find out the issues, will be back if I find something useful.