Finalize plugin initialization on demand.

This patch changes the way plugins are initialized. Instead of
finalizing all the plugins at once, plugins are finalized only after
they are accessed (currently applies to Command, Object and
Attribute subclasses, only in CLI by default).

This change provides significant performance boost, as only the
plugins that are actually used are finalized.

ticket 1336

1 files changed, 38 insertions, 25 deletions

diff --git a/ipalib/frontend.py b/ipalib/frontend.py
index 851de4379..3dc30daee 100644
--- a/ipalib/frontend.py
+++ b/ipalib/frontend.py
@@ -388,17 +388,20 @@ class Command(HasParam):
     ipalib.frontend.my_command()
     """
 
+    finalize_early = False
+
     takes_options = tuple()
     takes_args = tuple()
-    args = None
-    options = None
-    params = None
+    # Create stubs for attributes that are set in _on_finalize()
+    args = Plugin.finalize_attr('args')
+    options = Plugin.finalize_attr('options')
+    params = Plugin.finalize_attr('params')
     obj = None
 
     use_output_validation = True
-    output = None
+    output = Plugin.finalize_attr('output')
     has_output = ('result',)
-    output_params = None
+    output_params = Plugin.finalize_attr('output_params')
     has_output_params = tuple()
 
     msg_summary = None
@@ -411,6 +414,7 @@ class Command(HasParam):
         If not in a server context, the call will be forwarded over
         XML-RPC and the executed an the nearest IPA server.
         """
+        self.ensure_finalized()
         params = self.args_options_2_params(*args, **options)
         self.debug(
             'raw: %s(%s)', self.name, ', '.join(self._repr_iter(**params))
@@ -769,7 +773,7 @@ class Command(HasParam):
         """
         return self.Backend.xmlclient.forward(self.name, *args, **kw)
 
-    def finalize(self):
+    def _on_finalize(self):
         """
         Finalize plugin initialization.
 
@@ -799,7 +803,7 @@ class Command(HasParam):
         )
         self.output = NameSpace(self._iter_output(), sort=False)
         self._create_param_namespace('output_params')
-        super(Command, self).finalize()
+        super(Command, self)._on_finalize()
 
     def _iter_output(self):
         if type(self.has_output) is not tuple:
@@ -1040,19 +1044,21 @@ class Local(Command):
 
 
 class Object(HasParam):
-    backend = None
-    methods = None
-    properties = None
-    params = None
-    primary_key = None
-    params_minus_pk = None
+    finalize_early = False
+
+    # Create stubs for attributes that are set in _on_finalize()
+    backend = Plugin.finalize_attr('backend')
+    methods = Plugin.finalize_attr('methods')
+    properties = Plugin.finalize_attr('properties')
+    params = Plugin.finalize_attr('params')
+    primary_key = Plugin.finalize_attr('primary_key')
+    params_minus_pk = Plugin.finalize_attr('params_minus_pk')
 
     # Can override in subclasses:
     backend_name = None
     takes_params = tuple()
 
-    def set_api(self, api):
-        super(Object, self).set_api(api)
+    def _on_finalize(self):
         self.methods = NameSpace(
             self.__get_attrs('Method'), sort=False, name_attr='attr_name'
         )
@@ -1074,11 +1080,14 @@ class Object(HasParam):
                 filter(lambda p: not p.primary_key, self.params()), sort=False  #pylint: disable=E1102
             )
         else:
+            self.primary_key = None
             self.params_minus_pk = self.params
 
         if 'Backend' in self.api and self.backend_name in self.api.Backend:
             self.backend = self.api.Backend[self.backend_name]
 
+        super(Object, self)._on_finalize()
+
     def params_minus(self, *names):
         """
         Yield all Param whose name is not in ``names``.
@@ -1166,16 +1175,20 @@ class Attribute(Plugin):
     only the base class for the `Method` and `Property` classes.  Also see
     the `Object` class.
     """
-    __obj = None
+    finalize_early = False
+
+    NAME_REGEX = re.compile(
+        '^(?P<obj>[a-z][a-z0-9]+)_(?P<attr>[a-z][a-z0-9]+(?:_[a-z][a-z0-9]+)*)$'
+    )
+
+    # Create stubs for attributes that are set in _on_finalize()
+    __obj = Plugin.finalize_attr('_Attribute__obj')
 
     def __init__(self):
-        m = re.match(
-            '^([a-z][a-z0-9]+)_([a-z][a-z0-9]+(?:_[a-z][a-z0-9]+)*)$',
-            self.__class__.__name__
-        )
+        m = self.NAME_REGEX.match(type(self).__name__)
         assert m
-        self.__obj_name = m.group(1)
-        self.__attr_name = m.group(2)
+        self.__obj_name = m.group('obj')
+        self.__attr_name = m.group('attr')
         super(Attribute, self).__init__()
 
     def __get_obj_name(self):
@@ -1194,9 +1207,9 @@ class Attribute(Plugin):
         return self.__obj
     obj = property(__get_obj)
 
-    def set_api(self, api):
-        self.__obj = api.Object[self.obj_name]
-        super(Attribute, self).set_api(api)
+    def _on_finalize(self):
+        self.__obj = self.api.Object[self.obj_name]
+        super(Attribute, self)._on_finalize()
 
 
 class Method(Attribute, Command):