remove PLC.Debug.log, use PLC.Logger.logger instead

[plcapi.git] / PLC / Accessor.py

diff --git a/PLC/Accessor.py b/PLC/Accessor.py
index acf9a49..7352f47 100644 (file)
--- a/PLC/Accessor.py
+++ b/PLC/Accessor.py
@@ -1,33 +1,41 @@
-# $Id$
-# $URL$
 #
 # Thierry Parmentelat - INRIA
 #
 #
 # just a placeholder for storing accessor-related tag checkers
 # this is filled by the accessors factory
+#
+# NOTE. If you ever come to manually delete a TagType that was created
+# by the Factory, you need to restart your python instance / web server
+# as the cached information then becomes wrong
+
+from PLC.Logger import logger
 
 from PLC.TagTypes import TagTypes, TagType
+from PLC.Roles import Roles, Role
 
 # implementation
 class Accessor (object) :
-    """This is placeholder for storing accessor-related tag checkers
-methods in this class are defined by the accessors factory
+    """This is placeholder for storing accessor-related tag checkers.
+Methods in this class are defined by the accessors factory
 
 This is implemented as a singleton, so we can cache results over time"""
 
     _instance = None
 
+    tag_locators={}
+
     def __init__ (self, api):
         self.api=api
         # 'tagname'=>'tag_id'
         self.cache={}
+        self.hash_name_to_role=dict ( [ (role['name'],role) for role in Roles(api)] )
 
     def has_cache (self,tagname): return self.cache.has_key(tagname)
     def get_cache (self,tagname): return self.cache[tagname]
-    def set_cache (self,tagname,tag_id): self.cache[tagname]=tag_id
+    def set_cache (self,tagname,tag_type): self.cache[tagname]=tag_type
 
-    def locate_or_create_tag (self,tagname,category, description, min_role_id):
+    def locate_or_create_tag (self, tagname, category, description, roles, enforce=False):
         "search tag type from tagname & create if needed"
 
         # cached ?
@@ -37,18 +45,58 @@ This is implemented as a singleton, so we can cache results over time"""
         tag_types = TagTypes (self.api, {'tagname':tagname})
         if tag_types:
             tag_type = tag_types[0]
+            # enforce should only be set by the 'service plc start accessors' sequence
+            if enforce:
+                try:
+                    tag_type.update({'category':category,'description':description})
+                    tag_type.sync()
+                    roles_to_add = set(roles).difference(set(tag_type['roles']))
+                    for rolename in roles_to_add:
+                        tag_type.add_role(self.hash_name_to_role[rolename])
+                    roles_to_delete = set(tag_type['roles']).difference(set(roles))
+                    for rolename in roles_to_delete:
+                        tag_type.remove_role(self.hash_name_to_role[rolename])
+                except:
+                    logger.exception("WARNING, Could not enforce tag type, tagname={}\n"
+                                     .format(tagname))
+
+                    
         else:
             # not found: create it
             tag_type_fields = {'tagname':tagname,
                                'category' :  category,
-                               'description' : description,
-                               'min_role_id': min_role_id}
+                               'description' : description}
             tag_type = TagType (self.api, tag_type_fields)
             tag_type.sync()
-        tag_type_id = tag_type['tag_type_id']
-        self.set_cache(tagname,tag_type_id)
-        return tag_type_id
+            for role in roles:
+                try: 
+                    role_obj=Roles (self.api, role)[0]
+                    tag_type.add_role(role_obj)
+                except:
+                    # xxx todo find a more appropriate way of notifying this
+                    logger.exception("Accessor.locate_or_create_tag: "
+                                     "Could not add role {} to tag_type {}"
+                                     .format(role,tagname))
+        self.set_cache(tagname,tag_type)
+        return tag_type
+
+    # a locator is a function that retrieves - or creates - a tag_type instance
+    @staticmethod
+    def register_tag_locator (name, tag_locator):
+        Accessor.tag_locators[name]=tag_locator
 
+    @staticmethod
+    def retrieve_tag_locator (name):
+        return Accessor.tag_locators[name]
+    
+    # this is designed to be part of the 'service plc start' sequence
+    # it ensures the creation of all the tagtypes defined 
+    # in the various accessors, and enforces consistency to the DB
+    # it's not easy to have define_accessors do this because at
+    # load-time as we do not have an instance of API yet
+    def run_all_tag_locators (self):
+        for (name, tag_locator) in Accessor.tag_locators.items():
+            tag_locator(self,enforce=True)
 
 ####################
 # make it a singleton so we can cache stuff in there over time