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NAME
Logfile::Rotate - Perl module to rotate logfiles.
SYNOPSIS
use Logfile::Rotate;
my $log = new Logfile::Rotate( File => '/var/adm/syslog/syslog.log',
Count => 7,
Gzip => 'lib',
Post => sub{
open(IN, "/var/run/syslog.pid");
kill("HUP", chomp(<IN>)); }
Dir => '/var/log/old',
Flock => 'yes',
Persist => 'yes',
);
# process log file
$log->rotate();
or
my $log = new Logfile::Rotate( File => '/var/adm/syslog',
Gzip => '/usr/local/bin/gzip');
# process log file
$log->rotate();
undef $log;
DESCRIPTION
I have used the name space of the Logfile::Base manpage package by
*Ulrich Pfeifer*, as the use of this module closely relates to the
processing logfiles.
new `new' accepts the following arguments, `File', `Count', `Gzip',
`Pre', `Post', `Flock' and `Dir' with only `File' being mandatory.
`new' will open and lock the file, so you may co-ordinate the
processing of the file with rotating it. The file is closed and
unlocked when the object is destroyed, so you can do this explicitly
by `undef''ing the object.
The `Pre'/`Post' arguments allow you to pass function references to
this method, which you may use as a callback for any processing you
want before or after the rotation. For example, you may notify the
process writing to the file that it has been rotated.
The `Pre' function is passed the current filename to be rotated as
an argument and the `Post' function is passed the current filename
that was rotated and that file's new filename including any
extension added by compression previously.
Both the `Pre' and `Post' function references you provide are
executed within an `eval' statement inside the `rotate' method. If
the `eval' returns an error then the `rotate' method will croak at
that point.
The `Signal' argument is deprecated by the `Post' argument.
The `Flock' argument allows you to specify whether the perl function
`flock' is used to lock the file during the rotation operation.
Apparently flock causes problems on some platforms and this option
has been added to allow you to control the programs behaviour. By
default the file will be locked using `flock'.
The `Persist' argument allows you to control whether the program
will try and set the current log file ownership and permissions on
any new files that may be created by the rotation. In some
circumstances the program doing the file rotation may not have
sufficient permission to `chown' on the file. By default the program
will try and preserve ownership and permissions.
rotate()
This method will copy the file passed in `new' to a file of the same
name, with a numeric extension and truncate the original file to
zero length. The numeric extension will range from 1 up to the value
specified by Count, or 7 if none is defined, with 1 being the most
recent file. When Count is reached, the older file is discarded in a
FIFO (first in, first out) fashion. If the argument `Dir' was given,
all old files will be placed in the specified directory.
The `Post' function is the last step executed by the rotate method
so the return code of rotate will be the return code of the function
you proved, or 1 by default.
The copy function is implemented by using the the File::Copy manpage
package, but I have had a few people suggest that they would prefer
the File::Move manpage. I'm still not decided on this as you would
loose data if the move should fail.
Optional Compression
If available `rotate' will also compress the file with the the gzip
manpage program or the program passed as the `Gzip' argument.
You may now also use `lib' as a value for the `Gzip' argument. This
directs the program to load the `Compress::Zlib' module, if available
and use it do the compression within perl. This avoids the security
issues associated with spawning external programs and is the recommended
value for this option.
If no argument is defined it will first check to see if the
`Compress::Zlib' module can be loaded then check the perl the Config
manpage to determine if gzip is available on your system. In this case
the the gzip manpage must be in your current path to succeed, and accept
the `-f' option.
See the the section on "WARNING" section below.
Optional Relocation Directory
If you specify an argument for `Dir' then the file being rotated will be
relocated to the directory specified. Along with any other files that
may have been rotated previously. If the directory name specified does
not exist then it will be created with `0750' permissions. If you wish
to have other permissions on the directory then I would recommend you
create the directory before using this module.
See the the section on "WARNING" section below.
WARNING
If a system call is made to gzip this makes this module vulnerable to
security problems if a rogue gzip is in your path or gzip has been
sabotaged. For this reason a STRONGLY RECOMMEND you DO NOT use this
module while you are ROOT.
For a more secure alternative install the `Compress::Zlib' module and
use the lib value for the `Gzip' argument.
If you specify an argument for `Dir' and the directory name you pass
does not exist, this module will create the directory with permissions
`0750'.
DEPENDANCIES
See the File::Copy manpage.
If `Gzip' is being used it must create files with an extension of `.gz'
for the file to be picked by the rotate cycle.
COPYRIGHT
Copyright (c) 1997-99 Paul Gampe. All rights reserved. This program is
free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES
THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
THIS SOFTWARE IS PROVIDED ON AN ``AS IS'' BASIS, AND THE AUTHORS AND
DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
SEE ALSO
the File::Copy manpage, the Logfile::Base manpage, the flock manpage
Changes file for change history and credits for contributions.
RETURN
All functions return 1 on success, 0 on failure.
AUTHOR
Paul Gampe <paulg@apnic.net>
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