/ 
App-YG-0.063
River stage zero No dependents
/ yg

NAME

yg - log line filter, like \G of MySQL

SYNOPSIS

$ yg [options] FILE ...

or

$ cat apache_log | yg [option]

options:
    -p,  --parser         parser(default: apache-combined)
         --tab            show tab delimited log
         --space          show space delimited log
                          NOTE: if you set options --tab or --space, then --parser option is ignored
         --ltsv           parsed and show LTSV log
    -n,  --number         if you specify delimiter and -n, then show number points
    -m,  --match          show log lines only if a keyword matches
    -re, --regexp         show log lines only if regular expression matches
    -i,  --ignore-case    regexp option: ignore case distinctions
    -r,  --raw            also show raw log lines
    -t,  --through        ignore yg command, output only raw log lines
         --digest         show digest of raw log string

    -c, --color           show colorized log

    -h,  --help           show this help message
    -V,  --version        show version

EXAMPLES

parse Apache Combined logs, show logs vertically with labels of element

$ yg apache_commbined_log

parse Apache Error logs, show logs vertically with labels of element

$ yg -p apache-error apache_error_log

parse TAB-delimited logs, show logs vertically

$ yg --tab tab_delimited_log

parse TAB-delimited logs, show logs vertically with number labels

$ yg --tab -n tab_delimited_log

parse SPACE-delimited logs, show logs vertically

$ yg --space space_delimited_log

parse LTSV logs, show logs vertically

$ yg --ltsv ltsv_log

tailed log

$ tail -f apache_commbined_log | yg

DESCRIPTION

yg is a log viewer(filter) to show log lines vertically.

When you check apache logs, I guess you do like this

$ cat apache_log
127.0.0.1 - - [30/Sep/2012:12:34:56 +0900] "GET /foo HTTP/1.0" 200 123 "http://example.com/foo" "Mozilla/5.0"
127.0.0.1 - - [30/Sep/2012:12:34:57 +0900] "GET /bar HTTP/1.0" 301 124 "http://example.com/bar" "Mozilla/5.1"

If you use yg, log lines are showed like below:

$ yg apache_log
******************** 1 ********************
     Host: 127.0.0.1
    Ident: -
 Authuser: -
     Date: 30/Sep/2012:12:34:56 +0900
  Request: GET /foo HTTP/1.0
   Status: 200
    Bytes: 123
  Referer: http://example.com/foo
UserAgent: Mozilla/5.0

******************** 2 ********************
     Host: 127.0.0.1
    Ident: -
 Authuser: -
     Date: 30/Sep/2012:12:34:57 +0900
  Request: GET /bar HTTP/1.0
   Status: 200
    Bytes: 124
  Referer: http://example.com/bar
UserAgent: Mozilla/5.1

easier for understanding.

Of course, yg can work for like below.

$ cat apache_log | yg

yg command supports few formats of log. And you can write custom parser of App::YG.

PARSERS

Above sample uses App::YG::Apache::Combined. It is default parser. If you want to view other format logs, you should specify --parser option.

$ cat apache-error-log | yg --parser apache-error

Then yg uses App::YG::Apache::Error to parse log lines.

$ cat apache-error-log | yg --parser apache-error
******************** 1 ********************
     Date: Sat Oct 06 17:34:17 2012
Log_Level: error
   Client: 127.0.0.1
  Message: File does not exist: /var/www/html/favicon.ico

App::YG has below parsers.

App::YG::Apache::Combined

for apache combined log

App::YG::Apache::Common

for apache common log

App::YG::Apache::Error

for apache error log

App::YG::Nginx::Main

for nginx main log

HOW TO WRITE YOUR OWN PARSER

App::YG is designed to be easily extensible. You might want to write a custom log parser. Each parser is easy to write one.

For example:

package App::YG::MyApp::Log;
use strict;
use warnings;

sub parse {
    my $line = shift;

    $line =~ m!^DATE:([^\t]+)\t([^\t]+)\tMSG:(.+)$! or warn "failed to parse line: '$line'\n";

    return [
        $1 || '',
        $2 || '',
        $3 || '',
    ];
}

sub labels {
    return [qw/
        Date
        Level
        Message
    /];
}

Parser class must have 2 methods parser and labels. Both methods must return array reference. Let's look at the anatomy of App::YG::* modules. And check test codes in t/parser/*/*.t.

AUTHOR

Dai Okabayashi <bayashi@cpan.org>

SEE ALSO

App::YG

LICENSE

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