These are the scripts executed during installation and uninstallation of a module. For an RPM distributive these are ordinary PREIN, POSTIN, PREUN, POSTUN scripts. For shell-based distributives, the installation script will be contained in the self-extracting script body, while the uninstallation script is a separate file that will be executed during removal of a module from Plesk. This file should be located in the directory:

<PRODUCT_ROOT_D>/var/modules/<module name>/uninstall

In respect to Plesk, installation or uninstallation of a module will be carried out either by installing or uninstalling an RPM package, or by executing a shell script for Standard Plesk. Thus a module itself is responsible for its correct installation and registration. The modulemng utility is used for launching installation/uninstallation process.

Installation

The following actions should be performed during installation process:

• check if a module with such name is already installed. If it is, start update process.
• unpack module service and management files, if required
• set access permissions to the files
• create module-related tables in the Plesk database
• make service settings, if necessary (create databases, configuration files, etc.)
• launch the service, if necessary
• make a record on the installed module in the Modules table of the Plesk database
• extract images for module files, move them to the htdocs/images/modules/ directory, save the file name for the access button to the module in the icon field of the Modules table.

See example of installation scripts.

Uninstallation

To uninstall a module, you need to uninstall an RPM package or simply execute a /var/modules/<module_name>/uninstall shell script. The following actions should be perform during uninstallation process: 

• remove the record about the module from the Modules table
• stop the service, if necessary
• make an additional cleanup, if necessary (remove a module-related database, etc.)
• remove module service files, if necessary
• remove image files
• remove module management files.

See example of uninstallation scripts.