DNS resolver can run for longer than the given timeout

It's very hard to reproduce, we found the problem because we have a 60s timeout for our web server that we kept busting, even with email-validator's default 15s timeout.

Disabling check_availability solved our problem.

The problem

The problem lies within:

response = dns_resolver.resolve(domain, "MX")

( https://github.com/JoshData/python-email-validator/blob/main/email_validator/deliverability.py#L40 )

While debugging, what I can see is that the resolver goes through a loop, and only checks the timeout between calls. It also does some time.sleep()
That means that if a call or a sleep is longer than the timeout, it doesn't get interrupted and can thus run for longer

The solution

Using signal, we could interrupt the process. See https://stackoverflow.com/a/494273

This package does it: https://github.com/pnpnpn/timeout-decorator

I'll try implementing the stackoverflow suggestion on my end and write back with news

Comienza en deliverability.py, en la llamada a dns_resolver.resolve(domain, "MX"), y sigue cómo se pasa el tiempo de espera configurado cuando check_availability está habilitado. Reproduce o investiga el bucle del resolver y el comportamiento de sleep descritos en el issue. Se considera terminado cuando la resolución DNS no se ejecuta más allá del tiempo de espera indicado y se conserva el comportamiento existente de deliverability.