NAME
CGI::Application::Plugin::LogDispatch - Add Log::Dispatch support to
CGI::Application
SYNOPSIS
use CGI::Application::Plugin::LogDispatch;
$self->log->info('Information message');
$self->log->debug('Debug message');
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.
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));
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 $log = shift;
if ($ENV{'REMOTE_USER'}) {
$log->info("user ".$ENV{'REMOTE_USER'});
}
# etc...
}
BUGS
This is alpha software and as such, the features and interface are
subject to change. So please check the Changes file when upgrading.
SEE ALSO
CGI::Application, Log::Dispatch, Log::Dispatch::Screen,
Sub::WrapPackages, perl(1)
AUTHOR
Cees Hek <cees@crtconsulting.ca>
LICENSE
Copyright (C) 2004 Cees Hek <cees@crtconsulting.ca>
This library is free software. You can modify and or distribute it under
the same terms as Perl itself.