Add JSON output support to knot DNS probe script

[bebehei]

This adds conditional support to output JSON in the mod-probe support portal. Condition --json as the argument.

Makes it much easier to convert this as a e.g. elasticsearch ingest or similar for observability.

Since the official gitlab.nic.cz is closed and it seems, contributions are accepted here, too, I've chosen a GitHub PR.

[salzmdan]

Thanks! We will check soon.

[Dook97]

Hi @bebehei and thanks a lot for your contribution!

Your code is good, so we've adopted it with only minor changes. Could you take a look and tell us whether the end result is fine with you? We'll merge once you give your OK.

FYI: This Github repo is just a mirror of our Gitlab. If you'd like to contribute more in the future, we'd be happy to create an account for you there.

[bebehei]

As far as I can see, you changed the print logic, especially just the flush=True.

Without verfying further: This should not be necessary, since print also spits out a newline and python is line buffered on stdout anyways. Forced flushes improve latency, but limit throughput. I don't see what you're trying to optimize for. But, you do you.

My main goal was to contribute back the JSON logic. Others can be faster now to start ingesting their DNS queries into elasticsearch/whatever.

Props for keeping up the commit in original form!

--

If I will do other commits, I'll ask for account on your GitLab.

Thanks!

[salzmdan]

Merged as https://gitlab.nic.cz/knot/knot-dns/-/commit/1729a53709214a28b218e00b7a04bfa33042ccd2.