FileRotate(3) User Contributed Perl Documentation FileRotate(3)NAMELog::Dispatch::FileRotate - Log to files that archive/rotate themselves
SYNOPSIS
use Log::Dispatch::FileRotate;
my $file = Log::Dispatch::FileRotate->new( name => 'file1',
min_level => 'info',
filename => 'Somefile.log',
mode => 'append' ,
size => 10,
max => 6,
);
# or for a time based rotation
my $file = Log::Dispatch::FileRotate->new( name => 'file1',
min_level => 'info',
filename => 'Somefile.log',
mode => 'append' ,
TZ => 'AEDT',
DatePattern => 'yyyy-dd-HH',
);
$file->log( level => 'info', message => "your comment\n" );
DESCRIPTION
This module provides a simple object for logging to files under the
Log::Dispatch::* system, and automatically rotating them according to
different constraints. This is basically a Log::Dispatch::File wrapper
with additions. To that end the arguments
name, min_level, filename and mode
behave the same as Log::Dispatch::File. So see its man page (perldoc
Log::Dispatch::File)
The arguments size and max specify the maximum size and maximum number
of log files created. The size defaults to 10M and the max number of
files defaults to 1. If DatePattern is not defined then we default to
working in size mode. That is, use size values for deciding when to
rotate.
Once DatePattern is defined FileRotate will move into time mode. Once
this happens file rotation ignores size constraints and uses the
defined date pattern constraints.
If you setup a config file using Log::Log4perl::init_and_watch() or the
like, you can switch between modes just by commenting out the
DatePattern line.
When using DatePattern make sure TZ is defined correctly and that the
TZ you use is understood by Date::Manip. We use Date::Manip to generate
our recurrences. Bad TZ equals bad recurrences equals surprises! Read
the Date::Manip man page for more details on TZ.
DatePattern will default to a daily rotate if your entered pattern is
incorrect. You will also get a warning message.
If you have multiple writers that were started at different times you
will find each writer will try to rotate the log file at a recurrence
calculated from its start time. To sync all the writers just use a
config file and update it after starting your last writer. This will
cause Log::Dispatch::FileRotate->new() to be called by each of the
writers close to the same time, and if your recurrences aren't too
close together all should sync up just nicely.
I initially aasumed a long runinng process but it seems people are
using this module as part of short running CGI programs. So, now we
look at the last modified time stamp of the log file and compare it to
a previous occurance of a DatePattern, on startup only. If the file
stat shows the mtime to be earlier than the previous recurrance then I
rotate the log file.
We handle multiple writers using flock().
DatePattern
As I said earlier we use Date::Manip for generating our recurrence
events. This means we can understand Date::Manip's recurrence patterns
and the normal log4j DatePatterns. We don't use DatePattern to define
the extension of the log file though.
DatePattern can therefore take forms like:
Date::Manip style
0:0:0:0:5:30:0 every 5 hours and 30 minutes
0:0:0:2*12:30:0 every 2 days at 12:30 (each day)
3*1:0:2:12:0:0 every 3 years on Jan 2 at noon
DailyRollingFileAppender log4j style
yyyy-MM every month
yyyy-ww every week
yyyy-MM-dd every day
yyyy-MM-dd-a every day at noon
yyyy-MM-dd-HH every hour
yyyy-MM-dd-HH-MM every minute
To specify multiple recurrences in a single string separate them with a
semicolon:
yyyy-MM-dd; 0:0:0:2*12:30:0
This says we want to rotate every day AND every 2 days at 12:30. Put in
as many as you like.
A complete description of Date::Manip recurrences is beyond us here
except to quote (from the man page):
A recur description is a string of the format
Y:M:W:D:H:MN:S . Exactly one of the colons may
optionally be replaced by an asterisk, or an asterisk
may be prepended to the string.
Any value "N" to the left of the asterisk refers to
the "Nth" one. Any value to the right of the asterisk
refers to a value as it appears on a calendar/clock.
Values to the right can be listed a single values,
ranges (2 numbers separated by a dash "-"), or a comma
separated list of values or ranges. In a few cases,
negative values are appropriate.
This is best illustrated by example.
0:0:2:1:0:0:0 every 2 weeks and 1 day
0:0:0:0:5:30:0 every 5 hours and 30 minutes
0:0:0:2*12:30:0 every 2 days at 12:30 (each day)
3*1:0:2:12:0:0 every 3 years on Jan 2 at noon
0:1*0:2:12,14:0:0 2nd of every month at 12:00 and 14:00
1:0:0*45:0:0:0 45th day of every year
0:1*4:2:0:0:0 4th tuesday (day 2) of every month
0:1*-1:2:0:0:0 last tuesday of every month
0:1:0*-2:0:0:0 2nd to last day of every month
METHODS
· new(%p)
This method takes a hash of parameters. The following options are
valid:
· -- name ($)
The name of the object (not the filename!). Required.
· -- size ($)
The maxium (or close to) size the log file can grow too.
· -- max ($)
The maxium number of log files to create.
· -- TZ ($)
The TimeZone time based calculations should be done in. This should
match Date::Manip's concept of timezones and of course your
machines timezone.
· -- DatePattern ($)
The DatePattern as defined above.
· -- min_level ($)
The minimum logging level this object will accept. See the
Log::Dispatch documentation for more information. Required.
· -- max_level ($)
The maximum logging level this obejct will accept. See the
Log::Dispatch documentation for more information. This is not
required. By default the maximum is the highest possible level
(which means functionally that the object has no maximum).
· -- filename ($)
The filename to be opened for writing. This is the base name.
Rotated log files will be renamed filename.1 thru to
filename."max". Where max is the paramater defined above.
· -- mode ($)
The mode the file should be opened with. Valid options are
'write', '>', 'append', '>>', or the relevant constants from Fcntl.
The default is 'write'.
· -- autoflush ($)
Whether or not the file should be autoflushed. This defaults to
true.
· -- callbacks( \& or [ \&, \&, ... ] )
This parameter may be a single subroutine reference or an array
reference of subroutine references. These callbacks will be called
in the order they are given and passed a hash containing the
following keys:
( message => $log_message, level => $log_level )
The callbacks are expected to modify the message and then return a
single scalar containing that modified message. These callbacks
will be called when either the "log" or "log_to" methods are called
and will only be applied to a given message once.
· -- DEBUG ($)
Turn on lots of warning messages to STDERR about what this module
is doing if set to 1. Really only useful to me.
· log_message( message => $ )
Sends a message to the appropriate output. Generally this
shouldn't be called directly but should be called through the
"log()" method (in Log::Dispatch::Output).
· setDatePattern( $ or [ $, $, ... ] )
Set a new suite of recurrances for file rotation. You can pass in a
single string or a reference to an array of strings. Multiple
recurrences can also be define within a single string by seperating
them with a semi-colon (;)
See the discussion above regarding the setDatePattern paramater for
more details.
TODO
compression, signal based rotates, proper test suite
Could possibly use Logfile::Rotate as well/instead.
AUTHOR
Mark Pfeiffer, <markpf at mlp-consulting dot com dot au> inspired by
Dave Rolsky's, <autarch at urth dot org>, code :-)
Kevin Goess <cpan at goess dot org> suggested multiple writers should
be supported. He also conned me into doing the time based stuff.
Thanks Kevin! :-)
Thanks also to Dan Waldheim for helping with some of the locking issues
in a forked environment.
And thanks to Stephen Gordon for his more portable code on lockfile
naming.
Copyright
Copyright 2005-2006, Mark Pfeiffer
This code may be copied only under the terms of the Artistic License,
or GPL License which may be found in the Perl 5 source kit.
Use 'perldoc perlartistic' to see the Artistic License. Use 'perldoc
perlgpl' to see the GNU General Public License.
Complete documentation for Perl, including FAQ lists, should be found
on this system using `man perl' or `perldoc perl'. If you have access
to the Internet, point your browser at http://www.perl.org/, the Perl
Home Page.
POD ERRORS
Hey! The above document had some coding errors, which are explained
below:
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Expected '=item *'
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Expected '=item *'
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perl v5.14.1 2008-10-20 FileRotate(3)
