RetryAgent and fetch

[zbinlin]

I tried to use fetch with RetryAgent, but it doesn't seem to work well.

import { RetryAgent, Agent, fetch } from "undici";
const agent = new RetryAgent(new Agent());
const res = await fetch("https://www.example.org", {
    dispatcher: agent,
});

When a HeadersTimeoutError occurs, it does not retry the request but instead throws the error.

Does the fetch supports RetryAgent?

[metcoder95]

By default, the RetryHandler does not recognizes undici's error codes as retriable, you can expand that by adding more errorCodes while creating the RetryAgent, e.g.

import { createServer } from "node:http"
import { once } from "node:events"
import { RetryAgent, Agent, fetch } from "./index.js";

const server = createServer((req, res) => {
    setTimeout(() => {
        res.writeHead(200, { "Content-Type": "text/plain" });
        res.end('Hello World');
    }, 1000)
})

server.listen();
await once(server, 'listening')

const agent = new RetryAgent(new Agent({ headersTimeout: 500 }), {
    errorCodes: ['UND_ERR_HEADERS_TIMEOUT'],
});
const { port } = server.address()
const res = await fetch(`http://localhost:${port}`, {
    dispatcher: agent,
});