Alternative AccessLog Middleware
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Plack::Middleware::AxsLog - Yet another AccessLog Middleware


use Plack::Builder;

builder {
    enable 'AxsLog',
      combined => 1,
      response_time => 1,
      error_only => 1,


Alternative implementation of Plack::Middleware::AccessLog. This middleware supports response_time and content_length calculation AxsLog also can set condition to display logs by response_time and status code.

Originally, AxsLog was faster AccessLog implementation. But PM::AccessLog became to using same access-log generator module Apache::LogFormat::Compiler. Two middlewares have almost same performance now.


  • combined: Bool

    log format. if disabled, "common" format used. default: 1 (combined format used)

    common (Common Log Format) format is

    %h %l %u %t \"%r\" %>s %b
    => - - [23/Aug/2012:00:52:15 +0900] "GET / HTTP/1.0" 200 645

    combined (NCSA extended/combined log format) format is

    %h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"
    => - - [23/Aug/2012:00:52:15 +0900] "GET / HTTP/1.1" 200 645 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.79 Safari/537.1"
  • ltsv: Bool

    use ltsv log format. default: 0

    LTSV (Labeled Tab-separated Values) format is

    => host:<TAB>user:-<TAB>time:[23/Aug/2012:00:52:15 +0900]<TAB>req:GET / HTTP/1.1<TAB>status:200<TAB>size:645<TAB>"referer:-<TAB>ua:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.79 Safari/537.1

    See also

  • format: String

    A format string.

    builder {
        enable 'AxsLog', 
            format => '%h %l %u %t "%r" %>s %b "%{Referer}i" "%{User-agent}i" %D';

    See details on perldoc Apache::LogFormat::Compiler

  • format_options

    This variable is passed to Apache::LogFormat::Compiler. You can add char_handlers and block_handlers with this middleware.

    enable 'AxsLog', 
        format => '%z %{X_MYAPP_VARIABLE}Z', 
        format_options => +{
            char_handlers => +{
                'z' => sub { 'z' },
            block_handlers => +{
                'Z' => sub { 'Z' },
  • response_time: Bool

    Adds time taken to serve the request. default: 0. This args effect to common, combined and ltsv format.

  • error_only: Bool

    Display logs if response status is error (4xx or 5xx). default: 0

  • long_response_time: Int (microseconds)

    Display log if time taken to serve the request is above long_response_time. default: 0 (all request logged)

  • logger: Coderef

    Callback to print logs. default:none ( output to psgi.errors )

    use File::RotateLogs;
    my $logger = File::RotateLogs->new();
    builder {
        enable 'AxsLog',
          logger => sub { $logger->print(@_) }


Masahiro Nagano




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