Posting this in the hopes that it’ll help someone at some point….

Using Apache (Apache2 in my case, but I’m not sure it matters), you can customize the format for log files like access_log. Apache has a good page describing the variables you can use. But it doesn’t tell you everything you need to know!

The first question is where you put it… You can just specify it in httpd.conf (I put it near the end, but I don’t think its placement matters terribly, as long as it’s not in the middle of a section. It doesn’t go in any directives or anything. You can also insert it inside a VirtualHost directive if you only want it to apply to those. (Don’t put it inside a Directory directive!)

The second thing is something that’s not really specified anywhere: specifying a LogFormat without then specifying a CustomLog directive accomplishes nothing! I wanted to keep Apache logging in the default directory (/var/log/apache2/access_log on Gentoo), so I just set the LogFormat to something I wanted. And nothing happened.

You specify the format in CustomLog as well, so it’s handy to use LogFormat to assign a “nickname”:

LogFormat "%h %l %u %t "%r" %>s %b "%{Referer}i" "%{User-agent}i"" n1zyy
CustomLog /var/log/apache2/access_log n1zyy

The first line sets the “n1zyy” ‘nickname’ to refer to to the format I specify. The next line sets a “custom” log file (in this case, it’s the same as the default, but I digress. It won’t work if I don’t specify it.) Then I tell it to use the format named “n1zyy.”

Once this is set up, you want to reload Apache, since it won’t notice your changes until you do.