Provided by: mtpolicyd_2.05-1_all 
NAME
Mail::MtPolicyd::Cookbook::ExtendedModule - how to achieve certain tasks within a plugin
VERSION
version 2.05
Extending your mtpolicyd plugin
How to achieve common task within your plugin.
Logging
You can output log messages to the mail.log from within your plugin by calling:
$self->log( $r, '<log message>' );
The log() method is inherited from the Plugin base class.
The default log_level used is 4.
To debug your plugin you can overwrite the log_level in your plugins configuration:
<Plugin hello-world>
module = "HelloWorld"
log_level = 2
</Plugin>
This will cause your plugin to log with an higher log_level of 2.
Caching lookup results
If your plugin is called from the smtpd_recipient_restrictions if will be called once for
every recipient. If your plugin does an lookup (dns, database, ...) should cache the
result.
The Mail::MtPolicyd::Request object implements the method do_cached() to achieve this:
my ( $ip_result, $info ) = $r->do_cached('rbl-'.$self->name.'-result',
sub { $self->_rbl->check( $ip ) } );
The first parameter is the key in the session to store the cached result. The second
parameter is a function reference.
It will check if there's already an result stored in the given key within the session. In
this case it will return the cached result as an array. If there is no result it will
execute the code reference, store the result within the session and will also return an
array containing the return values of the result.
Doing things only once per mail
If your plugin is called from the smtpd_recipient_restrictions if will be called once for
every recipient but some tasks should only be performed once per mail.
The Mail::MtPolicyd::Request object implements the method is_already_done() to achieve
this:
if( defined $self->score && ! $r->is_already_done( $self->name.'-score' ) ) {
$self->add_score($r, $self->name => $self->score);
}
The method takes the key in the session in which the flag is stored.
The example above will add a new score to the scoring, but only once per mail since the
session is persisted across different checks.
Use scoring
To add scoring to your plugin your plugin needs to consume the role
Mail::MtPolicyd::Plugin::Role::Scoring.
This will add the method add_score( $r, $key, $value ) to your plugin class.
The $key is a name for the score you'll see when you display the detailed scores. eg. with
the AddScoreHeader or ScoreAction plugin.
The $value is positive or negative number. In most cases you want to make this value
configurable.
It is also recommended that you check that you add an score only once. See
is_already_done() method above.
Here is an example:
with 'Mail::MtPolicyd::Plugin::Role::Scoring';
has 'score' => ( is => 'rw', isa => 'Maybe[Num]' );
And somewhere in your run() method:
if( defined $self->score && ! $r->is_already_done( $self->name.'-score' ) ) {
$self->add_score( $r, $self->name => $self->score );
}
Make a configuration value user-configurable
To add user configurable parameters to your plugin the class must consume the
Mail::MtPolicyd::Plugin::Role::UserConfig role.
with 'Mail::MtPolicyd::Plugin::Role::UserConfig' => {
'uc_attributes' => [ 'enabled', 'mode' ],
};
The regular attributes:
has 'enabled' => ( is => 'rw', isa => 'Str', default => 'on' );
has 'mode' => ( is => 'rw', isa => 'Str', default => 'reject' );
The UserConfig role adds the get_uc( $session, $param ) method to your class. To retrieve
the user-configurable values for this attributes use:
my $session = $r->session;
my $mode = $self->get_uc( $session, 'mode' );
my $enabled = $self->get_uc( $session, 'enabled' );
Per user configuration in mtpolicyd works like this:
Retrieve configuration values and store them in the session
A plugin like SqlUserConfig retrieves configuration values and stores them in the
current session.
For example it may set the following key value:
hello_world_enabled = off
A Plugin with user configurable parameters
Our HelloWorld plugin may be configured like this:
<Plugin hello-world>
module = "HelloWorld"
enabled = on
uc_enabled = "hello_world_enabled"
</Plugin>
If the key "hello_world_enabled" is defined in the session it will use its value for
$mode. If it is not defined it will fall back to value of the "enabled" attribute.
Set a mail header
The Mail::MtPolicyd::Plugin::Result object has an extra constructor for returning a
PREPEND action for setting a header:
Mail::MtPolicyd::Plugin::Result->new_header_once( $is_already_done, $header_name, $value );
It could be used like this:
return Mail::MtPolicyd::Plugin::Result->new_header_once(
$r->is_already_done( $self->name.'-tag' ),
$header_name, $value );
Adding periodically scheduled tasks
When mtpolicyd is called with the option --cron <task1,task2,...> it will execute all
plugins that implement a cron() function.
The function is expected to take the following parameters:
$plugin->cron( $server, @tasks );
By default mtpolicyd ships with a crontab that will execute the tasks hourly,daily,weekly
and monthly.
A plugin that implements a weekly task may look like this:
sub cron {
my $self = shift;
my $server = shift;
if( grep { $_ eq 'weekly' } @_ ) {
# do some weekly tasks
$server->log(3, 'i am a weekly task');
}
}
The $server object could be used for logging.
To see the output on the command line you may call mtpolicyd like this:
mtpolicyd -f -l 4 --cron=weekly
AUTHOR
Markus Benning <ich@markusbenning.de>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2014 by Markus Benning <ich@markusbenning.de>.
This is free software, licensed under:
The GNU General Public License, Version 2, June 1991
perl v5.32.1 2021-12Mail::MtPolicyd::Cookbook::ExtendedPlugin(3pm)