ConstError in tiramisu/error.py

storage_type is now unique
rename _const => _NameSpace
can change storage's options in set_storage

storage :
add Setting object in storage
rename enumerate to list_sessions
rename delete to delete_session
auto-create owner when load sqlite3 storage and in getowner

tiramisu/setting.py

@@ -22,7 +22,8 @@
 # ____________________________________________________________
 from time import time
 from copy import copy
-from tiramisu.error import RequirementError, PropertiesOptionError
+from tiramisu.error import (RequirementError, PropertiesOptionError,
+                            ConstError, ConfigError)
 from tiramisu.i18n import _
 
 
@@ -34,28 +35,46 @@ ro_append = ('frozen', 'disabled', 'validator', 'everything_frozen',
 rw_remove = ('permissive', 'everything_frozen', 'mandatory')
 rw_append = ('frozen', 'disabled', 'validator', 'hidden')
 default_properties = ('expire', 'validator')
-storage_type = 'dictionary'
 
 
-class _const:
+class StorageType:
+    default_storage = 'dictionary'
+    storage_type = None
+
+    def set_storage(self, name):
+        if self.storage_type is not None:
+            raise ConfigError(_('storage_type is already set, cannot rebind it'))
+        self.storage_type = name
+
+    def get_storage(self):
+        if self.storage_type is None:
+            storage = self.default_storage
+        else:
+            storage = self.storage_type
+        return 'tiramisu.storage.{0}.storage'.format(
+            storage)
+
+
+storage_type = StorageType()
+
+
+class _NameSpace:
     """convenient class that emulates a module
     and builds constants (that is, unique names)"""
-    class ConstError(TypeError):
-        pass
 
     def __setattr__(self, name, value):
         if name in self.__dict__:
-            raise self.ConstError, _("can't rebind group ({})").format(name)
+            raise ConstError(_("can't rebind {0}").format(name))
         self.__dict__[name] = value
 
     def __delattr__(self, name):
         if name in self.__dict__:
-            raise self.ConstError, _("can't unbind group ({})").format(name)
+            raise ConstError(_("can't unbind {0}").format(name))
         raise ValueError(name)
 
 
 # ____________________________________________________________
-class GroupModule(_const):
+class GroupModule(_NameSpace):
     "emulates a module to manage unique group (OptionDescription) names"
     class GroupType(str):
         """allowed normal group (OptionDescription) names
@@ -87,7 +106,7 @@ populate_groups()
 
 
 # ____________________________________________________________
-class OwnerModule(_const):
+class OwnerModule(_NameSpace):
     """emulates a module to manage unique owner names.
 
     owners are living in `Config._cfgimpl_value_owners`
@@ -124,7 +143,7 @@ def populate_owners():
 populate_owners()
 
 
-class MultiTypeModule(_const):
+class MultiTypeModule(_NameSpace):
     "namespace for the master/slaves"
     class MultiType(str):
         pass
@@ -184,9 +203,17 @@ class Property(object):
         return str(list(self._properties))
 
 
-def set_storage(name):
-    global storage_type
-    storage_type = name
+def set_storage(name, **args):
+    storage_type.set_storage(name)
+    settings = __import__(storage_type.get_storage(), globals(), locals(),
+                          ['Setting'], -1).Setting()
+    for option, value in args.items():
+        try:
+            getattr(settings, option)
+            setattr(settings, option, value)
+        except AttributeError:
+            raise ValueError(_('option {0} not already exists in storage {1}'
+                               '').format(option, name))
 
 
 def get_storage(context, session_id, is_persistent):
@@ -195,9 +222,8 @@ def get_storage(context, session_id, is_persistent):
 
     if session_id is None:
         session_id = gen_id(context)
-    import_lib = 'tiramisu.storage.{0}.storage'.format(storage_type)
-    return __import__(import_lib, globals(), locals(), ['Storage'],
-                      -1).Storage(session_id, is_persistent)
+    return __import__(storage_type.get_storage(), globals(), locals(),
+                      ['Storage'], -1).Storage(session_id, is_persistent)
 
 
 #____________________________________________________________