NAME¶
CGI::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');
}
DESCRIPTION¶
CGI::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 accessible 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.
