perl logging - ghdrako/doc_snipets GitHub Wiki
By default Log::Log4perl will print to the STDERR (Standard error) channel which is by default connected to the screen.
use Log::Log4perl qw(:easy); #load the module importing the :easy key that will import 6 functions for the 6 logging levels provided by Log::Log4perl and 6 variables with corresponding names
Log::Log4perl->easy_init($WARN); #set the minimal log-level to be WARN
FATAL "This is", " fatal";
ERROR "This is error";
WARN "This is warn";
INFO "This is info"; # not show
DEBUG "This is debug";
TRACE "This is trace"; # not show
use Log::Log4perl qw(:easy);
DEBUG("message");
INFO("message");
WARN("message");
ERROR("message");
FATAL("message");
Turn off logging
Log::Log4perl->easy_init($OFF);
Using methods
use Log::Log4perl qw(:easy);
Log::Log4perl->easy_init($WARN);
my $logger = Log::Log4perl->get_logger();
$logger->fatal( "This is", " fatal");
$logger->error( "This is error");
$logger->warn( "This is warn");
$logger->info( "This is info");
$logger->debug( "This is debug");
$logger->trace( "This is trace");
use Log::Log4perl ();
use Log::Log4perl::Level ();
Log::Log4perl->easy_init(Log::Log4perl::Level::to_priority( 'WARN' ));
my $logger = Log::Log4perl->get_logger();
$logger->fatal( "This is", " fatal");
$logger->error( "This is error");
$logger->warn( "This is warn");
$logger->info( "This is info");
$logger->debug( "This is debug");
$logger->trace( "This is trace");
open FILE, "<blah" or die "Can't open blah -- bailing out!"; <---> open FILE, "<blah" or $log->logdie("Can't open blah -- bailing out!");
open FILE, "<blah" or LOGDIE "Can't open blah -- bailing out!";
###############################################################################
# Log::Log4perl Conf #
###############################################################################
log4perl.rootLogger = DEBUG, LOG1
log4perl.appender.LOG1 = Log::Log4perl::Appender::File
log4perl.appender.LOG1.filename = /var/log/mylog.log
log4perl.appender.LOG1.mode = append
log4perl.appender.LOG1.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.LOG1.layout.ConversionPattern = %d %p %m %n
#!/usr/bin/perl
use Log::Log4perl;
# Initialize Logger
my $log_conf = "/etc/log4perl.conf";
Log::Log4perl::init($log_conf);
my $logger = Log::Log4perl->get_logger();
# sample logging statement
$logger->info("this is an info log message");
#!/usr/bin/perl
use Log::Log4perl;
# Initialize Logger
my $log_conf = q(
log4perl.rootLogger = DEBUG, LOG1
log4perl.appender.LOG1 = Log::Log4perl::Appender::File
log4perl.appender.LOG1.filename = /var/log/mylog.log
log4perl.appender.LOG1.mode = append
log4perl.appender.LOG1.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.LOG1.layout.ConversionPattern = %d %p %m %n
);
Log::Log4perl::init(\$log_conf);
my $logger = Log::Log4perl->get_logger();
# sample logging statement
$logger->info("this is an info log message");
###############################################################################
# Log::Log4perl Conf #
###############################################################################
log4perl.rootLogger = DEBUG, LOG1, SCREEN
log4perl.appender.SCREEN = Log::Log4perl::Appender::Screen
log4perl.appender.SCREEN.stderr = 0
log4perl.appender.SCREEN.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.SCREEN.layout.ConversionPattern = %m %n
log4perl.appender.LOG1 = Log::Log4perl::Appender::File
log4perl.appender.LOG1.filename = /var/log/mylog.log
log4perl.appender.LOG1.mode = append
log4perl.appender.LOG1.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.LOG1.layout.ConversionPattern = %d %p %m %n
It should be noted, that the output to STDOUT is buffered and there is apparently no way of enabling autoflush so that it doesn't buffer the output.
############################################################
# A simple root logger with a Log::Log4perl::Appender::DBI #
############################################################
log4perl.rootLogger = INFO, DBI
log4perl.appender.DBI = Log::Log4perl::Appender::DBI
log4perl.appender.DBI.datasource=DBI:mysql:database=test;host=localhost;port=3306
log4perl.appender.DBI.username=guest
log4perl.appender.DBI.password=12345
log4perl.appender.DBI.sql=INSERT INTO log VALUES (0,?,?,?,?)
log4perl.appender.DBI.params.1=%F{1}
log4perl.appender.DBI.params.2=%d{yyyy-MM-dd HH:mm:ss}
log4perl.appender.DBI.params.3=%p
log4perl.appender.DBI.usePreparedStmt=1
log4perl.appender.DBI.layout=Log::Log4perl::Layout::NoopLayout
log4perl.appender.DBI.warp_message=0
--
-- Definition of table `log`
--
DROP TABLE IF EXISTS `log`;
CREATE TABLE `log` (
`log_id` int(11) NOT NULL auto_increment,
`log_source` varchar(100) NOT NULL default '',
`log_date` datetime NOT NULL default '0000-00-00 00:00:00',
`log_level` varchar(10) NOT NULL default '',
`log_mesg` varchar(200) NOT NULL default '',
PRIMARY KEY (`log_id`),
KEY `log_date_idx` (`log_date`),
KEY `log_source_idx` (`log_source`),
KEY `log_mesg_idx` (`log_mesg`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
SELECT * FROM mydb.log
Log::Log4perl can be used by Perl scripts or tools that need to write log messages to Syslog through the use of a special appender. This facility is provided in Log::Log4perl via the JavaMap::SyslogAppender which is a wrapper for the Log::Dispatch::Syslog module. To get this to work, you will need to install both Log::Log4perl, as well as, Log::Dispatch::Syslog. Our solution calls for a log4perl.conf file that would look like this:
############################################################
# A simple root logger using Log::Log4perl::JavaMap #
############################################################
log4j.appender.SyslogAppender = org.apache.log4j.SyslogAppender
log4j.appender.SyslogAppender.SyslogHost = localhost
log4j.appender.SyslogAppender.Facility = daemon
log4j.appender.SyslogAppender.layout = org.apache.log4j.PatternLayout
log4j.appender.SyslogAppender.ConversionPattern = %p: %m%n
Alternatively, you can always call the Log::Dispatch::Syslog code directly as follows:
############################################################
# Log::Log4perl conf - Syslog #
############################################################
log4perl.rootLogger = DEBUG, SYSLOG
log4perl.appender.SYSLOG = Log::Dispatch::Syslog
log4perl.appender.SYSLOG.min_level = debug
log4perl.appender.SYSLOG.ident = myprocess
log4perl.appender.SYSLOG.facility = daemon
log4perl.appender.SYSLOG.layout = Log::Log4perl::Layout::SimpleLayout
###############################################################################
# Log::Log4perl Conf #
###############################################################################
log4perl.logger.my_app = DEBUG, LOG1
log4perl.appender.LOG1 = Log::Log4perl::Appender::File
log4perl.appender.LOG1.filename = /var/log/mylog.log
log4perl.appender.LOG1.mode = append
log4perl.appender.LOG1.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.LOG1.layout.ConversionPattern = %d %p %m %n
# second logger points to the same file but with different level
log4perl.logger.my_other_app = INFO, LOG2
log4perl.appender.LOG2 = Log::Log4perl::Appender::File
log4perl.appender.LOG2.filename = /var/log/mylog.log
log4perl.appender.LOG2.mode = append
log4perl.appender.LOG2.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.LOG2.layout.ConversionPattern = %d %p %m %n
To utilize this configuration, suppose we have to separate Perl scripts named my_app.pl and my_other_app.pl. They would both initialize the Log::Log4perl using the same conf file. Immediately after instantiating the $logger object, the get_logger() method would be called by each script, passing in the value of the logger to get, as follows:
#!/usr/bin/perl
use Log::Log4perl;
# Initialize Logger
my $log_conf = "/etc/log4perl.conf";
Log::Log4perl::init($log_conf);
my $logger = Log::Log4perl->get_logger('my_app');
# sample logging statement
$logger->info("this is an info log message");
Oter aplication differ in:
$logger->get_logger('my_other_app');
Log::Any allows CPAN modules to safely and efficiently log messages, while letting the application choose
(or decline to choose) a logging mechanism such as Log::Dispatch or Log::Log4perl.
$cat log.pm
#!perl -w
# Log.pm -- a simple logger which uses DBI and DBD::CSV to
# handle all the file locking. All log entries are kept in
# a text file, to make reading it much easier than if they
# had been put into a real database.
# copyright September 23, 2001 by Michael S. Joyce
# [email protected]
# This code may be used and distributed under the same terms
# as Perl.
# TODO:
# add an option to make database connections
# happen with each call to logger(), instead of
# maintaining the connection for the lifetime of
# the program
use DBI;
use strict;
package Logger;
use vars qw($tbldefault $dbdefault);
# default name for the log file
$tbldefault="errlog";
# default directory for the log files
$dbdefault='E:\\\\log';
# check to see if a log file exists,
# and create it if it doesn't.
sub tblexists {
my $dbh = shift;
my $tblname = shift;
# $dbh->tables() is a new method in DBI version 1.09
unless (scalar grep {$_ eq $tblname} $dbh->tables())
{
my $crtstr=<<ENDQ;
CREATE TABLE $tblname(
date CHAR(24),
filename CHAR(24),
lineno CHAR(8),
message VARCHAR(256)
)
ENDQ
$dbh->do($crtstr) or die "creating table: $!\n$dbh->errstr";
}
}
# initialize the logger
# put a statement handle and database handle
# into self, as well as other potentially useful information
sub initialize {
my $self = shift;
$self->{'tblname'}=shift || $tbldefault;
$self->{'dbname'}=shift || $dbdefault;
$self->{'constr'}="DBI:CSV:f_dir=$self->{'dbname'}";
my $dbh = DBI->connect($self->{'constr'})
or die "No Database Connection Made: $!\n $DBI::errstr\n";
$self->{'dbhandle'}=$dbh;
tblexists($dbh, $self->{'tblname'});
my $instr="INSERT INTO $self->{'tblname'} VALUES (?,?,?,?)";
my $sth=$dbh->prepare($instr);
$self->{'sthandle'}=$sth;
}
# simple constructor
# most of the work is done in initialize()
sub new {
my $class = shift;
my $self = {};
bless $self, $class;
$self->initialize(@_);
return $self;
}
# member function to log a message
sub logger {
my $self = shift;
my $sth = $self->{'sthandle'};
my $time=localtime();
my $message = shift;
my ($package, $filename, $line) = caller;
$sth->execute($time, $filename, "line $line", $message);
}
# Destructor to cleanup database connections
sub DESTROY {
my $self = shift;
my $dbh = $self->{'dbhandle'};
$dbh->disconnect();
}
1;