Zur Installation von lokalen Utilities beim Zope-Start siehe Installation von Utilities beim Zope-Start.
Hier nur der nötige Programmcode, um den Kontext zu erhalten.

import transaction
from zope.app.intid.interfaces import IIntIds
from zope.app.catalog.interfaces import ICatalog
from zope.app.component import hooks

from zope.app import zapi
from zope.app.appsetup.bootstrap import ensureUtility, getInformationFromEvent
from zope.app.intid import IntIds

from zope.app.catalog.catalog import Catalog
from zope.app.catalog.field import FieldIndex

from exampleapp.interfaces import IColor

def bootStrapSubscriber(event):
    """Subscriber to the IDataBaseOpenedEvent

    Create local utilities if not yet present
    """
    db, connection, root, root_folder = getInformationFromEvent(event)
    ensureUtility(root_folder, IIntIds, '', IntIds, copy_to_zlog=False)
    ensureUtility(root_folder, ICatalog, '', Catalog, copy_to_zlog=False)
    catalog = zapi.getUtility(ICatalog, context=root_folder)
    if not catalog.get('interfaces'):
        try:
            # Die Installation eines Index erwartet Kontext, den Zope in
            # einer thread-globalen Variablen vorhält. Diese muss jetzt
            # gesetzt werden, weil die Site ja gerade erst erstellt wird.
            old_site = hooks.getSite()
            hooks.setSite(root_folder)
	    # add index
            catalog['color'] = FieldIndex('color', IColor, field_callable=False)
        finally:
            # Die alte Site wieder herstellen
            hooks.setSite(old_site)

    transaction.commit()
    connection.close()