=head1 Introduction

RT has a lot of core features, but sometimes you have a problem to solve
that's beyond the scope of just configuration. The standard way to add
features to RT is with an extension, or plugin -- RT uses the terms
interchangably.

=head1 Finding extensions

Most of the extensions written by Best Practical (and quite a few
contributed by the community) are available from CPAN; a L<search for
RT::Extension|https://metacpan.org/search?q=RT::Extension::> will turn
up most of them.  The Best Practical website also maintains a list, at
L<http://www.bestpractical.com/rt/extensions.html>

=head1 Installing extensions

RT extensions should be installed by downloading the C<.tar.gz> file for
the extensions, extracting it (with C<tar xzf filename.tar.gz>), and
following the instructions in its included F<README>.

The instructions under C<INSTALLING> in the F<README> always take
precedence over those found here.  In general, however, the process is
as follows:

=over

=item 1.

B<Run C<perl Makefile.PL>> to check for dependencies, and minimum
versions of RT.  If your RT is in an unusual location (not
C</opt/rt4/>), you may need to set the C<RTHOME> environment variable to
the root of your RT location.

=item 2.

B<Run C<make>> to prepare the package for installation.

=item 3.

B<Run C<make install>>; you may need to run this step as C<root>, or at
least a user that has permission to install into RT's directories.

=item 4.

If the extension contains database changes or new queues, scrips,
templates, or the like, you will need to B<run C<make initdb>> to install
them.  Not all extensions have database changes, and most of them only
need this step run when they are first installed, and not on later
updates.  Refer to the C<INSTALLING> section of the module's
documentation.

=item 5.

B<Add the plugin to RT's configuration.> By default, newly installed plugins
are not enabled.  On RT 4.2 and later, each plugin should be enabled by the
C<Plugin()> command:

    Plugin( 'RT::Extension::Example' );
    Plugin( 'RT::Extension::Sample' );


On RT 4.0, enabling them instead requires adding them to the C<@Plugins>
configuration:

    Set( @Plugins, 'RT::Extension::Example', 'RT::Extension::Sample' );

=item 6.

B<Configure any additional settings> that the extension requires.  Many
options that must be set before the plugin can be used.  Read the
documentation carefully.

=item 7.

Next, B<clear the cache>.  RT caches the files it serves, and installing
a plugin requires clearing this cache to ensure that the changes are
served.  This is done by removing files in the
F</opt/rt4/var/mason_data/obj> directory:

   rm -rf /opt/rt4/var/mason_data/obj

This step may not be necessary if the extension does not affect RT's
display.

=item 8.

Finally, B<restart your webserver>.  The steps for this will vary from
webserver to webserver.

=back

Again, the above are generalizations.  The C<README> shipped with the
extension always takes precedence over the above steps.


We do not suggest using the command-line C<cpan> or C<cpanm> client to
install RT extensions, despite them being available from CPAN.  Those
command-line clients are not aware of steps 4-8 listed above, and may
result in an incomplete installation.

=cut
