--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pyams_utils/interfaces/site.py	Wed Dec 05 12:45:56 2018 +0100
@@ -0,0 +1,60 @@
+#
+# Copyright (c) 2008-2015 Thierry Florac <tflorac AT ulthar.net>
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+
+__docformat__ = 'restructuredtext'
+
+
+# import standard library
+
+# import interfaces
+from zope.annotation.interfaces import IAttributeAnnotatable
+from zope.component.interfaces import IObjectEvent
+
+# import packages
+from zope.interface import Interface, Attribute
+
+
+class ISiteRoot(IAttributeAnnotatable):
+    """Marker interface for site root"""
+
+
+class ISiteRootFactory(Interface):
+    """Site root utility factory interface"""
+
+
+class INewLocalSiteCreatedEvent(IObjectEvent):
+    """Event interface when a new site root has been created"""
+
+
+class ISiteUpgradeEvent(IObjectEvent):
+    """Event interface when a site upgrade is requested"""
+
+
+SITE_GENERATIONS_KEY = 'pyams.generations'
+
+
+class ISiteGenerations(Interface):
+    """Site generations interface"""
+
+    order = Attribute("Order in which generations should be upgraded")
+    generation = Attribute("Current schema generation")
+
+    def evolve(self, site, current=None):
+        """Evolve database from current generation to last one"""
+
+
+class IConfigurationManager(IAttributeAnnotatable):
+    """Configuration manager marker interface"""
+
+
+class IOptionalUtility(Interface):
+    """Marker interface for site utilities that can be removed"""