Apache::LogFormat::Compiler(3)

NAME
Apache::LogFormat::Compiler - Compile a log format string to perl-code

SYNOPSIS
  use Apache::LogFormat::Compiler;

  my $log_handler = Apache::LogFormat::Compiler->new("combined");
  my $log = $log_handler->log_line(
      $env,
      $res,
      $length,
      $reqtime,
      $time
  );

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

METHOD

new($fmt:String)
    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);
                  $env->{psgi.error}->print($log_handler->log_line(
                      $env,$res,6,$reqtime, $t0->[0]));
              }
          };
          $app
      };

ADD CUSTOM FORMAT STRING
Apache::LogFormat::Compiler allows one to add a custom format string

  my $log_handler = Apache::LogFormat::Compiler->new(
      '%z %{HTTP_X_FORWARDED_FOR|REMOTE_ADDR}Z',
      char_handlers => +{
          'z' => sub {
              my ($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.

AUTHOR
Masahiro Nagano <kazeburo@gmail.com>

SEE ALSO
Plack::Middleware::AccessLog, <http://httpd.apache.org/docs/2.2/mod/mod_log_config.html>

LICENSE
Copyright (C) Masahiro Nagano

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