This simple logging hook allows you to run a function when httpd enters the logging phase of a request. With it, you can append data to your own logs, manipulate data before the regular log is written, or prevent a log entry from being created. To prevent the usual logging from happening, simply return apache2.DONE in your logging handler, otherwise return apache2.OK to tell httpd to log as normal.

Example:

LuaHookLog "/path/to/script.lua" logger

-- /path/to/script.lua --
function logger(r)
 -- flip a coin:
 -- If 1, then we write to our own Lua log and tell httpd not to log
 -- in the main log.
 -- If 2, then we just sanitize the output a bit and tell httpd to 
 -- log the sanitized bits.
 if math.random(1,2) == 1 then
 -- Log stuff ourselves and don't log in the regular log
 local f = io.open("/foo/secret.log", "a")
 if f then
 f:write("Something secret happened at " .. r.uri .. "\n")
 f:close()
 end
 return apache2.DONE -- Tell httpd not to use the regular logging functions
 else
 r.uri = r.uri:gsub("somesecretstuff", "") -- sanitize the URI
 return apache2.OK -- tell httpd to log it.
 end
end