CGI::Application::PlugUserLContributedCGI::Application::Plugin::LogDispatch(3)NAMECGI::Application::Plugin::LogDispatch - Add Log::Dispatch support to
CGI::Application
SYNOPSIS
package My::App;
use CGI::Application::Plugin::LogDispatch;
sub cgiapp_init {
my $self = shift;
# calling log_config is optional as
# some simple defaults will be used
$self->log_config(
LOG_DISPATCH_MODULES => [
{ module => 'Log::Dispatch::File',
name => 'debug',
filename => '/tmp/debug.log',
min_level => 'debug',
},
]
);
}
sub myrunmode {
my $self = shift;
$self->log->info('Information message');
$self->log->debug('Debug message');
}
- or as a class based singleton -
package My::App;
use CGI::Application::Plugin::LogDispatch (
LOG_DISPATCH_MODULES => [
{ module => 'Log::Dispatch::File',
name => 'debug',
filename => '/tmp/debug.log',
min_level => 'debug',
},
]
);
My::App->log->info('Information message');
sub myrunmode {
my $self = shift;
$self->log->info('This also works');
}
DESCRIPTIONCGI::Application::Plugin::LogDispatch adds logging support to your
CGI::Application modules by providing a Log::Dispatch dispatcher object
that is accessible from anywhere in the application.
If you have CGI::Application::Plugin::DevPopup installed, a "Log
Entries" report is added to the popup window, containing all of the
entries that were logged during the execution of the runmode.
METHODS
log
This method will return the current Log::Dispatch dispatcher object.
The Log::Dispatch object is created on the first call to this method,
and any subsequent calls will return the same object. This effectively
creates a singleton log dispatcher for the duration of the request. If
"log_config" has not been called before the first call to "log", then
it will choose some sane defaults to create the dispatcher object (the
exact default values are defined below).
# retrieve the log object
my $log = $self->log;
$log->warning("something's not right!");
$log->emergency("It's all gone pear shaped!");
- or -
# use the log object directly
$self->log->debug(Data::Dumper::Dumper(\%hash));
- or -
# if you configured it as a singleton
My::App->log->debug('This works too');
log_config
This method can be used to customize the functionality of the
CGI::Application::Plugin::LogDispatch module. Calling this method does
not mean that a new Log::Dispatch object will be immediately created.
The log object will not be created until the first call to $self->log.
The recommended place to call "log_config" is in the "cgiapp_init"
stage of CGI::Application. If this method is called after the log
object has already been accessed, then it will die with an error
message.
If this method is not called at all then a reasonable set of defaults
will be used (the exact default values are defined below).
The following parameters are accepted:
LOG_DISPATCH_OPTIONS
This allows you to customize how the Log::Dispatch object is
created by providing a hash of options that will be passed to the
Log::Dispatch constructor. Please see the documentation for
Log::Dispatch for the exact syntax of the parameters. Surprisingly
enough you will usually not need to use this option, instead look
at the LOG_DISPATCH_MODULES option.
LOG_DISPATCH_OPTIONS => {
callbacks => sub { my %h = @_; return time().': '.$h{message}; },
}
LOG_DISPATCH_MODULES
This option allows you to specify the Log::Dispatch::* modules that
you wish to use to log messages. You can list multiple dispatch
modules, each with their own set of options. Format the options in
an array of hashes, where each hash contains the options for the
Log::Dispatch:: module you are configuring and also include a
'module' parameter containing the name of the dispatch module. See
below for an example. You can also add an 'append_newline' option
to automatically append a newline to each log entry for this
dispatch module (this option is not needed if you already specified
the APPEND_NEWLINE option listed below which will add a newline for
all dispatch modules).
LOG_DISPATCH_MODULES => [
{ module => 'Log::Dispatch::File',
name => 'messages',
filename => '/tmp/messages.log',
min_level => 'info',
append_newline => 1
},
{ module => 'Log::Dispatch::Email::MailSend',
name => 'email',
to => [ qw(foo@bar.com bar@baz.org ) ],
subject => 'Oh No!!!!!!!!!!',
min_level => 'emerg'
}
]
APPEND_NEWLINE
By default Log::Dispatch does not append a newline to the end of
the log messages. By setting this option to a true value, a
newline character will automatically be added to the end of the log
message.
APPEND_NEWLINE => 1
LOG_METHOD_EXECUTION (EXPERIMENTAL)
This option will allow you to log the execution path of your
program. Set LOG_METHOD_EXECUTION to a list of all the modules you
want to be logged. This will automatically send a debug message at
the start and end of each method/function that is called in the
modules you listed. The parameters passed, and the return value
will also be logged. This can be useful by tracing the program
flow in the logfile without having to resort to the debugger.
LOG_METHOD_EXECUTION => [qw(__PACKAGE__ CGI::Application CGI)],
WARNING: This hasn't been heavily tested, although it seems to
work fine for me. Also, a closure is created around the log
object, so some care may need to be taken when using this in a
persistent environment like mod_perl. This feature depends on the
Sub::WrapPackages module.
DEFAULT OPTIONS
The following example shows what options are set by default (ie this is
what you would get if you do not call log_config). A single
Log::Dispatch::Screen module that writes error messages to STDERR with
a minimum log level of debug.
$self->log_config(
LOG_DISPATCH_MODULES => [
{ module => 'Log::Dispatch::Screen',
name => 'screen',
stderr => 1,
min_level => 'debug',
append_newline => 1
}
],
);
Here is a more customized example that uses two file appenders, and an
email gateway. Here all debug messages are sent to /tmp/debug.log, and
all messages above are sent to /tmp/messages.log. Also, any emergency
messages are emailed to foo@bar.com and bar@baz.org.
$self->log_config(
LOG_DISPATCH_MODULES => [
{ module => 'Log::Dispatch::File',
name => 'debug',
filename => '/tmp/debug.log',
min_level => 'debug',
max_level => 'debug'
},
{ module => 'Log::Dispatch::File',
name => 'messages',
filename => '/tmp/messages.log',
min_level => 'info'
},
{ module => 'Log::Dispatch::Email::MailSend',
name => 'email',
to => [ qw(foo@bar.com bar@baz.org ) ],
subject => 'Oh No!!!!!!!!!!',
min_level => 'emerg'
}
],
APPEND_NEWLINE => 1,
);
EXAMPLE
In a CGI::Application module:
# configure the log modules once during the init stage
sub cgiapp_init {
my $self = shift;
# Configure the session
$self->log_config(
LOG_DISPATCH_MODULES => [
{ module => 'Log::Dispatch::File',
name => 'messages',
filename => '/tmp/messages.log',
min_level => 'error'
},
{ module => 'Log::Dispatch::Email::MailSend',
name => 'email',
to => [ qw(foo@bar.com bar@baz.org ) ],
subject => 'Oh No!!!!!!!!!!',
min_level => 'emerg'
}
],
APPEND_NEWLINE => 1,
);
}
sub cgiapp_prerun {
my $self = shift;
$self->log->debug("Current runmode: ".$self->get_current_runmode);
}
sub my_runmode {
my $self = shift;
my $log = $self->log;
if ($ENV{'REMOTE_USER'}) {
$log->info("user ".$ENV{'REMOTE_USER'});
}
# etc...
}
SINGLETON SUPPORT
This module can be used as a singleton object. This means that when
the object is created, it will remain accessable for the duration of
the process. This can be useful in persistent environments like
mod_perl and PersistentPerl, since the object only has to be created
one time, and will remain in memory across multiple requests. It can
also be useful if you want to setup a DIE handler, or WARN handler,
since you will not have access to the $self object.
To use this module as a singleton you need to provide all configuration
parameters as options to the use statement. The use statement will
accept all the same parameters that the log_config method accepts, so
see the documentation above for more details.
When creating the singleton, the log object will be saved in the
namespace of the module that created it. The singleton will also be
inherited by any subclasses of this module.
NOTE: Singleton support requires the Class::ISA module which is not
installed automatically by this module.
SINGLETON EXAMPLE
package My::App;
use base qw(CGI::Application);
use CGI::Application::Plugin::LogDispatch(
LOG_DISPATCH_MODULES => [
{ module => 'Log::Dispatch::File',
name => 'messages',
filename => '/tmp/messages.log',
min_level => 'error'
},
],
APPEND_NEWLINE => 1,
);
}
sub cgiapp_prerun {
my $self = shift;
$self->log->debug("Current runmode: ".$self->get_current_runmode);
}
sub my_runmode {
my $self = shift;
my $log = $self->log;
if ($ENV{'REMOTE_USER'}) {
$log->info("user ".$ENV{'REMOTE_USER'});
}
# etc...
}
package My::App::Subclass;
use base qw(My::App);
# Setup a die handler that uses the logger
$SIG{__DIE__} = sub { My::App::Subclass->log->emerg(@_); CORE::die(@_); };
sub my_other_runmode {
my $self = shift;
$self->log->info("This will log to the logger configured in My::App");
}
BUGS
Please report any bugs or feature requests to
"bug-cgi-application-plugin-logdispatch@rt.cpan.org", or through the
web interface at <http://rt.cpan.org>. I will be notified, and then
you'll automatically be notified of progress on your bug as I make
changes.
SEE ALSO
CGI::Application, Log::Dispatch, Log::Dispatch::Screen,
Sub::WrapPackages, perl(1)AUTHOR
Cees Hek <ceeshek@gmail.com>
LICENSE
Copyright (C) 2004 Cees Hek <ceeshek@gmail.com>
This library is free software. You can modify and or distribute it
under the same terms as Perl itself.
perl v5.14.12011CGI::Application::Plugin::LogDispatch(3)