NAME

File::Write::Rotate - Write to files that archive/rotate themselves

VERSION

version 0.02

SYNOPSIS

use File::Write::Rotate;

my $fwr = File::Write::Rotate->new(
    dir       => '/var/log',    # required
    prefix    => 'myapp',       # required
    #suffix   => '.log',        # default is ''
    size      => 25*1024*1024,  # default is 10MB, unless period is set
    histories => 12,            # default is 10
);

# write, will write to /var/log/myapp.log, automatically rotate old log files
# to myapp.log.1 when myapp.log reaches 25MB. will keep old log files up to
# myapp.log.12.
$fwr->write("This is a line\n");
$fwr->write("This is", " another line\n");

# compress old log files
$fwr->compress;

DESCRIPTION

This module can be used to write to file, usually for logging, that can rotate itself. File will be opened in append mode. Locking will be done to avoid conflict when there are multiple writers. Rotation can be done by size (after a certain size is reached), by time (daily/monthly/yearly), or both.

I first wrote this module for logging script STDERR output to files (see Tie::Handle::FileRotate).

ATTRIBUTES

METHODS

$obj = File::Write::Rotate->new(%args)

Create new object. Known arguments:

• dir => STR (required)

  Directory to put the files in.

• prefix => STR (required)

  Name of files. The files will be named like the following:

  <prefix><period><suffix><rotate_suffix>

  <period> will only be given if the period argument is set. If period is set to yearly, <period> will be YYYY (4-digit year). If period is monthly, <period> will be YYYY-MM (4-digit year and 2-digit month). If period is daily, <period> will be YYYY-MM-DD (4-digit year, 2-digit month, and 2-digit day).

  <rotate_suffix> is either empty string for current file; or .1, .2 and so on for rotated files. .1 is the most recent rotated file, .2 is the next most recent, and so on.

  An example, with prefix set to myapp:

  myapp         # current file
  myapp.1       # most recently rotated
  myapp.2       # the next most recently rotated

  With prefix set to myapp, period set to monthly, suffix set to .log:

  myapp.2012-12.log     # file name for december 2012
  myapp.2013-01.log     # file name for january 2013

  Like previous, but additionally with size also set (which will also rotate each period file if it exceeds specified size):

  myapp.2012-12.log     # file(s) for december 2012
  myapp.2012-12.log.1
  myapp.2012-12.log.2
  myapp.2013-01.log     # file(s) for january 2013

  All times will use local time, so you probably want to set TZ environment variable or equivalent methods to set time zone.

• suffix => STR (default: '')

  Suffix to give to file names, usually file extension like .log. See prefix for more details.

  If you use a yearly period, setting suffix is advised to avoid ambiguity with rotate suffix (for example, is myapp.2012 the current file for year 2012 or file with 2012 rotate suffix?)

• size => INT (default: 10*1024*1024)

  Maximum file size, in bytes, before rotation is triggered. The default is 10MB (10*1024*1024) if period is not set. If period is set, no default for size is provided, which means files will not be rotated for size (only for period).

• histories => INT (default: 10)

  Number of rotated files to keep. After the number of files exceeds this, the oldest one will be deleted. 0 means not to keep any history, 1 means to only keep .1 file, and so on.

$fwr->write(@args)

Write to file. Will automatically rotate file if period changes or file size exceeds specified limit. When rotating, will only keep a specified number of histories and delete the older ones. Uses locking, so multiple writers do not clobber one another. Lock file is named <prefix>.lck. Will wait for up to 1 minute to acquire lock, will die if failed to acquire lock.

Does not append newline so you'll have to do it yourself.

$fwr->compress

Compress old rotated files. Currently uses pigz or gzip program to do the compression. Extension given to compressed file is .gz.

Normally, should be done using a separate process so as to avoid blocking the writers.

Will not lock writers, but will create <prefix>-compress.pid PID file to prevent multiple compression processes running and to signal the writers to postpone rotation.

After compression is finished, will remove the PID file, so rotation can be done again on the next write() if necessary.

SEE ALSO

Log::Dispatch::FileRotate, which inspires this module. Differences between File::Write::Rotate (FWR) and Log::Dispatch::FileRotate (LDFR) are as follows. Firstly, FWR is not part of the Log::Dispatch family. FWR does not use Date::Manip (to be tinier) and does not support DatePattern; instead, FWR replaces it with a simple daily/monthly/yearly period. FWR supports compressing and rotating compressed old files.

Tie::Handle::FileRotate, which uses this module.

AUTHOR

Steven Haryanto <stevenharyanto@gmail.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Steven Haryanto.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.