Logging in a web server context

["Carl Winbäck" <c@tunnel53.net>]

Hi folks!

Is it possible when using s6-svscan/s6-supervise to somehow arrange so
that a daemon’s stdout is sent to one logdir and stderr to another
logdir?

Or must I use s6-rc in order to achieve this?

My premises are the following:

I want to run nginx under s6, on a mainstream Linux distro such as
Debian/Ubuntu/CentOS. My plan is currently to use s6 only for nginx
and not any other daemons.

I want to collect the web server access logs in order to generate
visitor statistics[1].

One tricky aspect of logging that is specific to web servers is that
they emit two different categories of messages:

a) Errors and warnings

b) Info about page requests[2]

For many other kinds of daemons, one only needs to arrange for logging
stderr and then call it a day. With web servers it’s not quite so
simple.

I am very interested to hear from others on the list what your
thoughts are about this scenario.

The reason I’m weary about s6-rc is that I think it might not play so
well with the distros I mentioned earlier. If this concern is not
correct, please let me know.



[1] An alternative to collecting access logs could be to use Google
Analytics instead, but I want to avoid that since I don’t feel
comfortable about handing over my visitors’ personal data over to
Google.

[2] I.e. lines like this '10.131.214.101 - - [20/Nov/2017:18:52:17
+0000] "GET / HTTP/1.1" 401 188 "-" "Mozilla/5.0 (X11; Ubuntu; Linux
x86_64; rv:47.0) Gecko/20100101 Firefox/47.0"'