--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/source/site.rst	Sun Jan 14 11:48:51 2018 +0100
@@ -0,0 +1,73 @@
+.. _site:
+
+PyAMS site management
+=====================
+
+PyAMS site management is based on the ZODB.
+
+On application startup, if PyAMS_utils package is included into Pyramid configuration, several operations take
+place:
+
+ - a custom **site factory** is defined
+
+ - custom request methods are defined
+
+ - a custom **traverser** handling **namespaces** is defined
+
+ - a custom subscribers predicate based on interfaces support is defined
+
+ - several adapters are registered, to handle annotations and key references
+
+ - custom TALES extensions are registered.
+
+The site factory is an important component in this process. It is this factory which will define the application root
+and create a **local site manager**.
+
+Pyramid application is loaded from ZODB's root via a key defined in Pyramid's configuration file; the key is named
+*pyams.application_name* and it's default value is *application*.
+
+If the application can't be found, PyAMS is looking for an application class name in Pyramid's configuration file; the
+class name configuration key is called *pyams.application_factory* and defined by default as
+*pyams_utils.site.BaseSiteRoot*. PyAMS default site factory will then create the application, and add a local site
+manager to it (see :ref:`zca`).
+
+After application creation, a :py:class:`NewLocalSiteCreatedEvent <pyams_utils.site.NewLocalSiteCreatedEvent>` is
+notified. Custom packages can subscribe to this event to register custom components.
+
+
+*pyams_upgrade* command line script
+-----------------------------------
+
+Pyramid allows to define custom command line scripts for application management. A script called *pyams_upgrade* is
+provided by PyAMS_utils package; this script apply the same process as PyAMS site factory, but can also be used to
+manage **database generations**. The idea behind this is just to allow custom packages to provide a way to check and
+upgrade database configuration away from application startup process:
+
+.. code-block:: bash
+
+    # ./bin/pyams_upgrade webapp/development.ini
+
+
+A **site generation checker** is just a named utility providing :py:class:`pyams_utils.interfaces.site.ISiteGenerations`
+interface. For example, **pyams_security** package provides such utility, to make sure that local site manager
+contains a PyAMS security manager and a principal annotation utility:
+
+.. code-block:: python
+
+    from pyams_utils.site import check_required_utilities
+
+    REQUIRED_UTILITIES = ((ISecurityManager, '', SecurityManager, 'Security manager'),
+                          (IPrincipalAnnotationUtility, '', PrincipalAnnotationUtility, 'User profiles'))
+
+    @utility_config(name='PyAMS security', provides=ISiteGenerations)
+    class SecurityGenerationsChecker(object):
+    """I18n generations checker"""
+
+        generation = 1
+
+        def evolve(self, site, current=None):
+            """Check for required utilities"""
+            check_required_utilities(site, REQUIRED_UTILITIES)
+
+:py:func:`check_required_utilities <pyams_utils.site.check_required_utilities>` is a PyAMS_utils utility function which
+can to used to verify that a set of local utilities are correctly registered with the given names and interfaces.