Apache::LogFormat::Compiler(3) Compile a log format string to perl-code


use Apache::LogFormat::Compiler;
my $log_handler = Apache::LogFormat::Compiler->new("combined");
my $log = $log_handler->log_line(


Compile a log format string to perl-code. For faster generation of access_log lines.


Takes a format string (or a preset template "combined" or "custom") to specify the log format. This module implements a subset of Apache's LogFormat templates <http://httpd.apache.org/docs/2.0/mod/mod_log_config.html>:

   %%    a percent sign
   %h    REMOTE_ADDR from the PSGI environment, or -
   %l    remote logname not implemented (currently always -)
   %u    REMOTE_USER from the PSGI environment, or -
   %t    [local timestamp, in default format]
   %r    REQUEST_METHOD, REQUEST_URI and SERVER_PROTOCOL from the PSGI environment
   %s    the HTTP status code of the response
   %b    content length of the response
   %T    custom field for handling times in subclasses
   %D    custom field for handling sub-second times in subclasses
   %v    SERVER_NAME from the PSGI environment, or -
   %V    HTTP_HOST or SERVER_NAME from the PSGI environment, or -
   %p    SERVER_PORT from the PSGI environment
   %P    the worker's process id
   %m    REQUEST_METHOD from the PSGI environment
   %U    PATH_INFO from the PSGI environment
   %q    QUERY_STRING from the PSGI environment
   %H    SERVER_PROTOCOL from the PSGI environment

In addition, custom values can be referenced, using "%{name}", with one of the mandatory modifier flags "i", "o" or "t":

   %{variable-name}i    HTTP_VARIABLE_NAME value from the PSGI environment
   %{header-name}o      header-name header in the response
   %{time-format]t      localtime in the specified strftime format
log_line($env:HashRef, $res:ArrayRef, $length:Integer, $reqtime:Integer, $time:Integer): $log:String
Generates log line.

  $env      PSGI env request HashRef
  $res      PSGI response ArrayRef
  $length   Content-Length
  $reqtime  The time taken to serve request in microseconds. optional
  $time     Time the request was received. optional. If $time is undefined. current timestamp is used.

Sample psgi

  use Plack::Builder;
  use Time::HiRes;
  use Apache::LogFormat::Compiler;
  my $log_handler = Apache::LogFormat::Compiler->new(
      '%h %l %u %t "%r" %>s %b "%{Referer}i" "%{User-agent}i" %D'
  my $compile_log_app = builder {
      enable sub {
          my $app = shift;
          sub {
              my $env = shift;
              my $t0 = [gettimeofday];
              my $res = $app->();
              my $reqtime = int(Time::HiRes::tv_interval($t0) * 1_000_000);
                  $env,$res,6,$reqtime, $t0->[0]));

ABOUT POSIX::strftime::Compiler

This module uses POSIX::strftime::Compiler for generate datetime string. POSIX::strftime::Compiler provides GNU C library compatible strftime(3). But this module will not affected by the system locale. This feature is useful when you want to write loggers, servers and portable applications.


Apache::LogFormat::Compiler allows one to add a custom format string

  my $log_handler = Apache::LogFormat::Compiler->new(
      char_handlers => +{
          'z' => sub {
              my ($env,$req) = @_;
              return $env->{HTTP_X_FORWARDED_FOR};
      block_handlers => +{
          'Z' => sub {
              my ($block,$env,$req) = @_;
              # block eq 'HTTP_X_FORWARDED_FOR|REMOTE_ADDR'
              my ($main, $alt) = split('\|', $args);
              return exists $env->{$main} ? $env->{$main} : $env->{$alt};

Any single letter can be used, other than those already defined by Apache::LogFormat::Compiler. Your sub is called with two or three arguments: the content inside the "{}" from the format (block_handlers only), the PSGI environment ($env), and the ArrayRef of the response. It should return the string to be logged.


Masahiro Nagano <[email protected]>


Copyright (C) Masahiro Nagano

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.