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From: Robert J. <yad...@sn...> - 2006-09-22 17:24:46
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I've configured my program to log to a MySQL database using Log::Log4perl::Appender::DBI. However, if the database is not available, my program hangs on trying to write log messages. Is there a workaround for this? Thanks, Rob |
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From: John O. <joh...@o-...> - 2006-09-22 18:19:52
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I'd recommend writing another appender which wraps around Appender::DBI and checks for availability. Alternatively, write to a text log file for speed, then have a daily script which pushes the log entries into the DB. hope that helps, John Robert Jacobson wrote: >I've configured my program to log to a MySQL database using >Log::Log4perl::Appender::DBI. However, if the database is not >available, my program hangs on trying to write log messages. Is >there a workaround for this? > >Thanks, >Rob > > >------------------------------------------------------------------------- >Take Surveys. Earn Cash. Influence the Future of IT >Join SourceForge.net's Techsay panel and you'll get the chance to share your >opinions on IT & business topics through brief surveys -- and earn cash >http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV >_______________________________________________ >log4perl-devel mailing list >log...@li... >https://lists.sourceforge.net/lists/listinfo/log4perl-devel > > > |
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From: Robert J. <yad...@sn...> - 2006-09-26 17:54:43
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At 02:18 PM 9/22/2006, you wrote: >I'd recommend writing another appender which wraps around >Appender::DBI and checks for availability. Ok, having looked at some other options, this sounds like the way to go. But I have a noob question: How do I write that wrapper? I can handle writing the database availability code (I think! :) ) But I don't even know where to start for writing a wrapper to Appender::DBI. If it helps, I've written my own, albeit simple, Appender, that just implemented the new() and log() methods. -- Rob |
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From: Robert J. <yad...@sn...> - 2006-09-26 20:14:42
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At 02:18 PM 9/22/2006, John ORourke wrote:
>I'd recommend writing another appender which wraps around
>Appender::DBI and checks for availability.
Ok, I've managed to write a basic wrapper (without checking for
availability). It seems to work (i.e. messages are logged to the
database), but in the Layout I'm using %F{2}, and I get
"Log4perl/Logger.pm" instead of the path of my script. Do I need to
mess with caller_depth or something?
---------------------------------------------
package Mylog;
use warnings;
use strict;
require Log::Log4perl::Appender::DBI;
sub new {
my ($class, %options) = @_;
my $appender = Log::Log4perl::Appender::DBI->new(
map { $_ => $options{$_} } keys %options,
);
my $self = {
appender => $appender,
name => $options{name},
};
bless $self, $class;
return $self;
}
sub log {
my ($self, %p) = @_;
$self->{appender}->log(
%p,
);
return 1;
}
1;
---------------------------------------------
--
Rob
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From: Mike S. <m...@pe...> - 2006-09-27 05:46:58
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On Tue, 26 Sep 2006, Robert Jacobson wrote:
> At 02:18 PM 9/22/2006, John ORourke wrote:
> >I'd recommend writing another appender which wraps around
> >Appender::DBI and checks for availability.
>
> Ok, I've managed to write a basic wrapper (without checking for
> availability). It seems to work (i.e. messages are logged to the
> database), but in the Layout I'm using %F{2}, and I get
> "Log4perl/Logger.pm" instead of the path of my script. Do I need to
> mess with caller_depth or something?
If you're using wrapper classes, you need to adjust the caller level:
http://log4perl.sourceforge.net/d/Log/Log4perl.html#6acb7
-- Mike
Mike Schilli
m...@pe...
>
> ---------------------------------------------
>
> package Mylog;
>
> use warnings;
> use strict;
>
> require Log::Log4perl::Appender::DBI;
>
> sub new {
> my ($class, %options) = @_;
>
> my $appender = Log::Log4perl::Appender::DBI->new(
> map { $_ => $options{$_} } keys %options,
> );
>
> my $self = {
> appender => $appender,
> name => $options{name},
> };
>
> bless $self, $class;
>
> return $self;
>
> }
>
> sub log {
> my ($self, %p) = @_;
>
> $self->{appender}->log(
> %p,
> );
>
> return 1;
> }
>
> 1;
> ---------------------------------------------
>
> --
> Rob
>
>
> -------------------------------------------------------------------------
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to share your
> opinions on IT & business topics through brief surveys -- and earn cash
> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
> _______________________________________________
> log4perl-devel mailing list
> log...@li...
> https://lists.sourceforge.net/lists/listinfo/log4perl-devel
>
|
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From: Mike S. <m...@pe...> - 2006-09-27 05:49:56
|
On Tue, 26 Sep 2006, Robert Jacobson wrote:
> At 02:18 PM 9/22/2006, you wrote:
> >I'd recommend writing another appender which wraps around
> >Appender::DBI and checks for availability.
>
> Ok, having looked at some other options, this sounds like the way to
> go. But I have a noob question: How do I write that wrapper?
Similar to writing your own appender, just call the methods of the
'wrapped' appender from within your wrapper appender:
http://log4perl.sourceforge.net/d/Log/Log4perl/FAQ.html#e8a46
-- Mike
Mike Schilli
m...@pe...
>
> I can handle writing the database availability code (I think! :)
> ) But I don't even know where to start for writing a wrapper to Appender::DBI.
>
> If it helps, I've written my own, albeit simple, Appender, that just
> implemented the new() and log() methods.
>
> --
> Rob
>
>
> -------------------------------------------------------------------------
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to share your
> opinions on IT & business topics through brief surveys -- and earn cash
> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
> _______________________________________________
> log4perl-devel mailing list
> log...@li...
> https://lists.sourceforge.net/lists/listinfo/log4perl-devel
>
|
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From: Mike S. <m...@pe...> - 2006-09-28 02:20:38
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On Wed, 27 Sep 2006, Robert Jacobson wrote:
> However, the dumped log messages have the time of the dump, not the
> original log message time. Is there a way to get Log4perl to use the
> original time of the message?
Take a look at Log::Log4perl::Appender::Buffer, it does something similar:
# Trick the renderer into using the original event time
local $self->{app}->{layout}->{time_function};
$self->{app}->{layout}->{time_function} =
sub { $_->{log4p_logtime} };
It saves the event time when the log message comes in, saves it under the
'log4p_logtime' key and feeds it to the renderer later on.
-- Mike
Mike Schilli
m...@pe...
dd It doesn't seem to be in the hash that
> the log() method gets; but maybe I'm just not looking in the right spot?
>
> I guess I could workaround the issue by prepending the original time
> to the "message" field, but I'd like to avoid modifying the original
> as much as possible. Can I do something like: 1) store the original
> time internally in my buffer and 2) when dumping the buffer to the
> appender, set some internal Log4perl time variable to the buffered time?
>
> -----------------------------------------------------------
> package Mylog;
>
> use warnings;
> use strict;
>
> use Carp;
> use DBI;
>
> require Log::Log4perl::Appender::DBI;
>
> sub new {
> my ($class, %options) = @_;
>
> my $appender = Log::Log4perl::Appender::DBI->new(
> map { $_ => $options{$_} } keys %options,
> );
>
> my $self = {
> appender => $appender,
> name => $options{name},
> };
>
>
> bless $self, $class;
> $self->_init(%options);
>
> return $self;
>
> }
>
> sub log {
> my ($self, %p) = @_;
>
> # Check for DB connection
> if (! $self->{dbh}->ping() ) {
> # Buffer the message
> push @{$self->{BUFFER}}, \%p;
>
> # Notify FOT
> $self->_notify(%p);
> # Try to reconnect
> eval {
> $self->{dbh} = $self->{connect}->();
> };
> return 1;
> } else {
> $self->{connected_time} = scalar gmtime();
> }
>
> $self->check_buffer();
>
> $Log::Log4perl::caller_depth++;
>
> $self->{appender}->log(
> %p,
> );
>
> $Log::Log4perl::caller_depth--;
> return 1;
> }
>
> sub _init {
> my $self = shift;
> my %params = @_;
>
> if ($params{dbh}) {
> $self->{dbh} = $params{dbh};
> } else {
> $self->{connect} = sub {
> DBI->connect(@params{qw(datasource username password)},
> {PrintError => 0})
> or croak "Log4perl: $DBI::errstr";
> };
> $self->{dbh} = $self->{connect}->();
> $self->{_mine} = 1;
> }
> }
>
> sub _notify {
> my $self = shift;
> my %params = @_;
>
> # eventually send an email or something
> # for now just print a message
> print "Database is down\n";
>
> }
>
> sub check_buffer {
> my $self = shift;
>
> return unless ($self->{BUFFER} && ref $self->{BUFFER} eq 'ARRAY');
>
> while ( @{$self->{BUFFER}} ) {
> my $ref = shift @{$self->{BUFFER}};
> $Log::Log4perl::caller_depth += 2;
> $self->{appender}->log(
> %$ref,
> );
> $Log::Log4perl::caller_depth -= 2;
> }
>
> return 1;
> }
>
> 1;
>
> -----------------------------------------------------------
>
> --
> Rob
>
>
|
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From: Robert J. <yad...@sn...> - 2006-09-28 13:20:06
|
At 10:20 PM 9/27/2006, you wrote:
>Take a look at Log::Log4perl::Appender::Buffer, it does something similar:
Thanks much!
I'm using the DBI appender, with the NoopLayout and the data in
param.1, so I had to use:
$self->{appender}->{'bind_value_layouts'}{'1'}{'time_function'};
But it works great :)
Another question, mostly just curiousity -- I used Data::Dumper to
look at the appender structure. How/where does the time_function get
defined as sub {"DUMMY"}? I don't see that anywhere in the Log4perl
code... Is it a perl internal thing?
Below is an excerpt from the dump for the DBI appender.
$VAR1 = bless( {
'bind_value_layouts' => {
'6' => bless( {
'stack' => [
[
'm',
undef
]
],
'printformat' => '%s',
'dontCollapseArrayRefs' => undef,
'format' => undef,
'info_needed' => {
'm' => 1
},
'time_function' => sub { "DUMMY" },
'CSPECS' => 'cCdFHIlLmMnpPrtTxX%',
'message_chompable' => 0
}, 'Log::Log4perl::Layout::PatternLayout' ),
--
Rob
|
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From: Robert J. <yad...@sn...> - 2006-09-27 14:04:20
|
I've implemented a buffering mechanism in my wrapper's log()
call. Basically I check using {dbh}->ping() if the database is
up. If not, I buffer the message in an array and return success so
that the parent program can proceed.
When the database comes back up I dump the buffer to the DBI appender.
However, the dumped log messages have the time of the dump, not the
original log message time. Is there a way to get Log4perl to use the
original time of the message? It doesn't seem to be in the hash that
the log() method gets; but maybe I'm just not looking in the right spot?
I guess I could workaround the issue by prepending the original time
to the "message" field, but I'd like to avoid modifying the original
as much as possible. Can I do something like: 1) store the original
time internally in my buffer and 2) when dumping the buffer to the
appender, set some internal Log4perl time variable to the buffered time?
-----------------------------------------------------------
package Mylog;
use warnings;
use strict;
use Carp;
use DBI;
require Log::Log4perl::Appender::DBI;
sub new {
my ($class, %options) = @_;
my $appender = Log::Log4perl::Appender::DBI->new(
map { $_ => $options{$_} } keys %options,
);
my $self = {
appender => $appender,
name => $options{name},
};
bless $self, $class;
$self->_init(%options);
return $self;
}
sub log {
my ($self, %p) = @_;
# Check for DB connection
if (! $self->{dbh}->ping() ) {
# Buffer the message
push @{$self->{BUFFER}}, \%p;
# Notify FOT
$self->_notify(%p);
# Try to reconnect
eval {
$self->{dbh} = $self->{connect}->();
};
return 1;
} else {
$self->{connected_time} = scalar gmtime();
}
$self->check_buffer();
$Log::Log4perl::caller_depth++;
$self->{appender}->log(
%p,
);
$Log::Log4perl::caller_depth--;
return 1;
}
sub _init {
my $self = shift;
my %params = @_;
if ($params{dbh}) {
$self->{dbh} = $params{dbh};
} else {
$self->{connect} = sub {
DBI->connect(@params{qw(datasource username password)},
{PrintError => 0})
or croak "Log4perl: $DBI::errstr";
};
$self->{dbh} = $self->{connect}->();
$self->{_mine} = 1;
}
}
sub _notify {
my $self = shift;
my %params = @_;
# eventually send an email or something
# for now just print a message
print "Database is down\n";
}
sub check_buffer {
my $self = shift;
return unless ($self->{BUFFER} && ref $self->{BUFFER} eq 'ARRAY');
while ( @{$self->{BUFFER}} ) {
my $ref = shift @{$self->{BUFFER}};
$Log::Log4perl::caller_depth += 2;
$self->{appender}->log(
%$ref,
);
$Log::Log4perl::caller_depth -= 2;
}
return 1;
}
1;
-----------------------------------------------------------
--
Rob
|
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From: John O. <jo...@ve...> - 2006-09-27 17:25:33
|
Robert Jacobson wrote:
>I've implemented a buffering mechanism in my wrapper's log()
>call. Basically I check using {dbh}->ping() if the database is
>up. If not, I buffer the message in an array and return success so
>that the parent program can proceed.
>
>When the database comes back up I dump the buffer to the DBI appender.
>
>
I can't help with the timestamp issue but I'd recommend having a maximum
buffer size too, after which you stop saving up the messages - it could
be used on a system where the DB might be down for days in the event of
a disaster. Maybe if you're feeling very clever, revert to a file
appender if the DB is down!
cheers
John
|
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