NAME
Log::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 modebehave 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 minuteTo 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 monthMETHODS
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. Date::Manip will normally work everything out for you. Except in my case where EST means Eastern Standard Time in Australia not the US! I had to use AEST or EADT instead. Here is a list of Date::Manip's timezones straight from its man page.
The following timezone names are currently understood (and can be used in parsing dates). These are zones defined in RFC 822. Universal: GMT, UT US zones : EST, EDT, CST, CDT, MST, MDT, PST, PDT Military : A to Z (except J) Other : +HHMM or -HHMM ISO 8601 : +HH:MM, +HH, -HH:MM, -HH In addition, the following timezone abbreviations are also accepted. IDLW -1200 International Date Line West NT -1100 Nome HST -1000 Hawaii Standard CAT -1000 Central Alaska AHST -1000 Alaska-Hawaii Standard AKST -0900 Alaska Standard YST -0900 Yukon Standard HDT -0900 Hawaii Daylight AKDT -0800 Alaska Daylight YDT -0800 Yukon Daylight PST -0800 Pacific Standard PDT -0700 Pacific Daylight MST -0700 Mountain Standard MDT -0600 Mountain Daylight CST -0600 Central Standard CDT -0500 Central Daylight EST -0500 Eastern Standard SAT -0400 Chile EDT -0400 Eastern Daylight AST -0400 Atlantic Standard ADT -0300 Atlantic Daylight NDT -0230 Newfoundland Daylight AT -0200 Azores WAT -0100 West Africa GMT +0000 Greenwich Mean UT +0000 Universal (Coordinated) UTC +0000 Universal (Coordinated) WET +0000 Western European WEST +0000 Alias for Western European CET +0100 Central European FWT +0100 French Winter MET +0100 Middle European MEZ +0100 Middle European MEWT +0100 Middle European Winter SWT +0100 Swedish Winter BST +0100 British Summer bst=Brazil standard -0300 GB +0100 GMT with daylight savings CEST +0200 Central European Summer EET +0200 Eastern Europe, USSR Zone 1 FST +0200 French Summer MEST +0200 Middle European Summer MESZ +0200 Middle European Summer METDST +0200 An alias for MEST used by HP-UX SAST +0200 South African Standard SST +0200 Swedish Summer sst=South Sumatra +0700 EEST +0300 Eastern Europe Summer BT +0300 Baghdad, USSR Zone 2 MSK +0300 Moscow IT +0330 Iran ZP4 +0400 USSR Zone 3 MSD +0300 Moscow Daylight ZP5 +0500 USSR Zone 4 IST +0530 Indian Standard ZP6 +0600 USSR Zone 5 CCT +0800 China Coast, USSR Zone 7 AWST +0800 West Australian Standard WST +0800 West Australian Standard PHT +0800 Asia Manila JST +0900 Japan Standard, USSR Zone 8 ROK +0900 Republic of Korea CAST +0930 Central Australian Standard EAST +1000 Eastern Australian Standard GST +1000 Guam Standard, USSR Zone 9 gst=Greenland Std CADT +1030 Central Australian Daylight EADT +1100 Eastern Australian Daylight IDLE +1200 International Date Line East NZST +1200 New Zealand Standard NZT +1200 New Zealand NZDT +1300 New Zealand Daylight-- 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 => $log_level )The callbacks are expected to modify the message and then return a single scalar containing that modified message. These callbacks will be called when either the
logorlog_tomethods are called and will only be applied to a given message once.-- DEBUG ($)
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.
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