NAME
File::Tail::Lite - Perl module for seekable 'tailf' implementation
SYNOPSIS
Simple usage.
use File::Tail::Lite;
my $tailf = new File::Tail::Lite(filename => "/some_path/filename_for_tailf");
while(my $line) = $tailf->readline())
{
print $line;
}Get position everytime, so we will not miss any content when crash happens.
use File::Tail::Lite;
my $tailf = new File::Tail::Lite(filename => "/some_path/filename_for_tailf");
while(my ($pos, $line) = $tailf->readline())
{
print "[$pos,$line]";
}Seek to a position when start reading.
use File::Tail::Lite;
my $seekpos = sub_recover_pos();
my $tailf = new File::Tail::Lite(filename => "/some_path/filename_for_tailf", seekpos => $seekpos);
while(my ($pos, $line) = $tailf->readline())
{
print "[$pos,$line]";
$seekpos = $pos;
sub_save_pos($seekpos);
}Note that the above scripts will never exit. If there is nothing being written to the file, it will simply block.
DESCRIPTION
This module is made for seekable 'tailf' implementation.
File::Tail is good, but it can not seek when reading started,so we may miss contents if programe crash.
This module slove the problem.
And it is quite simple and easy to use.
METHOD
$file_tail_lite->readline()
return one line one time, blocks until that.
also return $self->{maxbuff} bytes if the line is too long to handle.
$file_tail_lite->{error}
0 : no error.
1 : error happened.
$file_tail_lite->{errinfo}
A string desc the error.
This will be set when $self->{error} == 1.
CONSTRUCTOR
new ([ ARGS])
- filename
-
The name of the file want to tailf.
- seekpos
-
default: 'eof'.
int - start reading from the specified offset
'begin' - read from the head of the file.
'eof' - read the new append contents only.
- maxbuf
-
default: 1024.
readline() returns a line by default.
set the max line length here, so that readline() can break long line.
EXAMPLE
use File::Tail::Lite;
use Storable qw(retrieve store);
my $stor_file = '/tmp/seekpos.tmp';
my $seekpos = retrieve($stor_file) || 'end';
my $tailf = new File::Tail::Lite(filename => "/var/log/httpd/access.log", seekpos => $seekpos, maxbuf => 100);
while(my ($pos, $line) = $tailf->readline())
{
print "[$pos,$line]";
store \$pos, $stor_file;
}
AUTHOR
Written by Chen Gang
yikuyiku.com@gmail.com
COPYRIGHT
Copyright (c) 2014 Chen Gang.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.