Why does the client.DoTimeout timeout setting have no effect?

[ljfuyuan]

Here is my core code

client := &fasthttp.Client{
	Name: "timeout-test-client",
}

req := fasthttp.AcquireRequest()
resp := fasthttp.AcquireResponse()

defer func() {
	fasthttp.ReleaseRequest(req)
	fasthttp.ReleaseResponse(resp)
}()

req.SetRequestURI("http://aaaa.com")
req.Header.SetMethod(fasthttp.MethodPost)
req.Header.SetContentType("application/json")
req.SetBodyRaw(body)

fmt.Println("###########start", start)
if err = client.DoTimeout(req, resp, time.Second*5); err != nil {
	fmt.Println("###########end", time.Now().Sub(start))
	return false, err
}
fmt.Println("###########end", time.Now().Sub(start))

And i got this:

###########start 2025-09-19 05:23:21.961335825 +0000 UTC m=+0.000482228
###########end 32.247683172s

Why do I still get a timeout result after 30 seconds even if I set a 5-second timeout?
Did I miss any setting? Thanks you all

[erikdubbelboer]

What is http://aaaa.com?

Can you give me an example that reproduces. For example this code times out after exactly 5 seconds as expected:

package main

import (
	"fmt"
	"time"

	"github.com/valyala/fasthttp"
)

func main() {
	client := &fasthttp.Client{
		Name: "timeout-test-client",
	}

	req := fasthttp.AcquireRequest()
	resp := fasthttp.AcquireResponse()

	defer func() {
		fasthttp.ReleaseRequest(req)
		fasthttp.ReleaseResponse(resp)
	}()

	req.SetRequestURI("https://dubbelboer.com/slow.php") // this url returns a response after 6 seconds.
	req.Header.SetMethod(fasthttp.MethodPost)
	req.Header.SetContentType("application/json")
	req.SetBodyRaw([]byte(`{"a":"b"}`))

	start := time.Now()
	if err := client.DoTimeout(req, resp, time.Second*5); err != nil {
		fmt.Println(time.Since(start), err)
	} else {
		fmt.Println(time.Since(start))
	}
}

% go run main.go
5.001719125s timeout

[ljfuyuan]

Thanks for your reply.
aaaa.com is just an example. I suspect the DNS or TCP connection is taking too long, causing the 5-second limit to be exceeded. By setting additional ReadTimeout and WriteTimeout, I can reduce the time to the limit.