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:

    %%    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.

RECOMMENDED MODULE

If POSIX::strftime::GNU is available, Apache::LogFormat::Compiler uses it. It's good for Windows and old Unices have limited strftime's formatting.

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.