Debugging with Nginx access logs

The Nginx access logs have been customised to include additional MageStack information for debugging.

A typical access log entry will look like this,

- -  10/Jul/2014:22:27:49 +0100 "GET /index.php" 200

The default format is "%R - %u %t \"%m %r\" %s"

Decompiling the log entry reveals,

Column Value Field
1 - Remote IP Address
2 - Remote User
3 10/Jul/2014:22:27:49 +0100 Server Time
4 GET Request Method
5 /index.php Request URI (without query string)
6 200 Response Code (status)

The full, available options for formatting are:

%C: %CPU used by the request
    it can accept the following format:
    - %{user}C for user CPU only
    - %{system}C for system CPU only
    - %{total}C  for user + system CPU (default)
%d: time taken to serve the request
    it can accept the following format:
    - %{seconds}d (default)
    - %{miliseconds}d
    - %{mili}d
    - %{microseconds}d
    - %{micro}d
%e: an environment variable (same as $_ENV or $_SERVER)
    it must be associated with embraces to specify the name of the env
    variable. Some exemples:
    - server specifics like: %{REQUEST_METHOD}e or %{SERVER_PROTOCOL}e
    - HTTP headers like: %{HTTP_HOST}e or %{HTTP_USER_AGENT}e
%f: script filename
%l: content-length of the request (for POST request only)
%m: request method
%M: peak of memory allocated by PHP
    it can accept the following format:
    - %{bytes}M (default)
    - %{kilobytes}M
    - %{kilo}M
    - %{megabytes}M
    - %{mega}M
%n: pool name
%o: ouput header
    it must be associated with embraces to specify the name of the header:
    - %{Content-Type}o
    - %{X-Powered-By}o
    - %{Transfert-Encoding}o
    - ....
%p: PID of the child that serviced the request
%P: PID of the parent of the child that serviced the request
%q: the query string
%Q: the '?' character if query string exists
%r: the request URI (without the query string, see %q and %Q)
%R: remote IP address
%s: status (response code)
%t: server time the request was received
    it can accept a strftime(3) format:
    %d/%b/%Y:%H:%M:%S %z (default)
%T: time the log has been written (the request has finished)
    it can accept a strftime(3) format:
    %d/%b/%Y:%H:%M:%S %z (default)
%u: remote user