Pulp

Create a base class for all future Content Units that stores information in MongoEngine

• The "AddUnitMixin.link_unit" functionality is currently only used when errata are created and is never read. This functionality does not need to be migrated to the unit model
• user_metadata field
• add a method add_content(source_location, relative_path)

source_location - the temp directory or location on disk where the plugin has stored the file or directory
relative_path - the relative path within /var/lib/pulp/content/content_type/<relative_path> where the content should be saved
when the unit is saved, if content has been added it will be moved into place in the content directory by the platform and the storage_path will be set the relative_path, use the post_save signal on the model

• add a property for the absolute storage path, this is a combination of pulp_config.config.get('server', 'storage_dir')/unit.content_type/unit.storage_path
• class method to set the _last_updated property and a signal hook on save to set or update the value
• The init should validate that the model implements a field for the content_type (this field should be persisted to the database)
• The init should validate that the model implements a property named unit_key_fields that lists the fields that make up the unit key (This is not persisted to the database)
• Method to get the list of repositories that contain the given unit. (This method will be a no/op until the Repository and the RepositoryContentUnit collection has been converted)

https://fedorahosted.org/pulp/wiki/ConvertingUnitsToMongoengine