[dnsdist] Logging a sample of queries

[Jacob Bunk Nielsen]

Hi

I want to log a sample of our DNS queries to dnsdist. We run dnsdist 
1.3.3 under systemd.

I have tried:

addAction(ProbaRule(0.01), LogAction())

I would expect this to log ~1/100 of our queries. But there's obviously 
a bug in the docs for dnsdist because LogAction() always require at 
least one argument. I couldn't find a good place to fix it and make a 
pull request. Should I make a github issue?

So I tried to supply '' (the empty string) as filename, which should 
make dnsdist log to stdout, but that only works with --verbose according 
to the docs which then again logs everything, so not exactly what I wanted.

I also tried to specify 'unix:/dev/log' as file name but apparently 
dnsdist don't want to log to a socket.

Ideally I just want dnsdist to log to stdout so systemd will pick up the 
output, but how can that be done without the --verbose option?

Best regards,

Jacob