Started receiving ErrConnectionClosed error on version 1.56.0

[chlp]

After upgrading to version 1.56.0, started encountering error ErrConnectionClosed

ErrConnectionClosed = errors.New("the server closed connection before returning the first response byte. " +
        "Make sure the server returns 'Connection: close' response header before closing the connection")

In my case, I was sending a POST request. There is an inverse correlation between the error rate and RPS:

• At 500 RPS, there are almost no errors: 0% most of the time with consistently high RPS, with occasional periods where errors are less than 0.1%
• At around 10 RPS, the error rate significantly increases to 10-20%

Rolled back to version 1.55.0, and the errors disappeared completely.

[newacorn]

In version 1.56.0, for non-idempotent requests, the framework will no longer automatically make retry decisions for users regardless of the error encountered. When the newly added field RetryIfErr is not configured by the user, the default retry strategy is to never retry non-idempotent requests.

    cli := HostClient{RetryIfErr: func(request *Request, attempts int, err error) (resetTimeout bool, retry bool) {
        isIdempotent := request.Header.IsGet() || request.Header.IsHead() || request.Header.IsPut()
        retry = true
        if !isIdempotent && err != io.EOF {
            retry = false
        }
        return
    }}

Defining RetryIfErr as shown below can replicate the behavior of version 1.55.0.

[chlp]

@newacorn wow, I see. I'll give it a try and come back to share results. Thank you so much!

[chlp]

yeah, it works, thanks again!

    fasthttp.Client{
        RetryIfErr: func(req *fasthttp.Request, attempts int, err error) (resetTimeout bool, retry bool) {
            if err == io.EOF {
                return false, true
            }
            return false, false
        },
    }