NAME

Krang::Upgrade - superclass for Krang upgrade modules

SYNOPSIS

  use Krang::ClassLoader base => 'Upgrade';

DESCRIPTION

This module is intended to be used as a parent class for Krang upgrade modules. It implements a harness for calling the per_installation() and per_instance() methods.

INTERFACE

To use this module, there are three things you have to do:

• use Krang::ClassLoader base => 'Upgrade';
  
This causes your upgrade module (e.g., ``V1_23.pm'') to inherit certain basic functionality. Specifically, an upgrade() method which calls per_installation(), and then calls per_instance() once for each instance.
• per_installation()
  
You must implement this method in your upgrade module. This method is called once per upgrade, before the per_instance() method is called.

This method is called (as an object method) by the inherited upgrade() method.

• per_instance()
  
You must implement this method in your upgrade module. This method is called once per Krang instance, after the per_installation() method is called.

This method is called (as an object method) by the inherited upgrade() method.

INHERITED METHODS

• new()
  
The new() method is a constructor which creates a trivial object from a hash. Your upgrade modules may use this to store state information.
• upgrade()
  
The upgrade() method is called by the krang_upgrade script to implement an upgrade. This method calls per_installation(), and then calls per_instance() once for each installed instance.

The following named parameters may be passed which will then get passed along to per_installation() and per_instance().

• no_db
  
This tells the upgrade module that the upgrade should not make changes to the database.

• remove_files()
  
This convenience method is provided to help remove old files during the upgrade. It's best to call this method in the per_installation() method since files are per-installation. File names are given relative to KRANG_ROOT.

    $self->remove_files(
        'lib/Krang/Foo.pm',
        'src/Foo-1.00.tar.gz',
    );

SEE ALSO

Releasing Krang: Creating Upgrade Modules docs/release.pod