X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=PLC%2FAccessor.py;h=e32add4b5016d5390de2eebf0d3f53e612a8f35c;hb=98423c5d9f2489f8d82dbe0cdd798ed33ed8f3b5;hp=fb12f3d8f74a2d04ecd81268938e5570db07ae78;hpb=fe32171e8722932e55d6c3e5b0df2acc34a1939f;p=plcapi.git diff --git a/PLC/Accessor.py b/PLC/Accessor.py index fb12f3d..e32add4 100644 --- a/PLC/Accessor.py +++ b/PLC/Accessor.py @@ -9,77 +9,109 @@ # 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 +class Accessor(object): + """ + This is a 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""" + Class is implemented as a singleton, so we can cache results over time + """ _instance = None - tag_locators={} + tag_locators = {} - def __init__ (self, api): - self.api=api + def __init__(self, api): + self.api = api # 'tagname'=>'tag_id' - self.cache={} + self.cache = {} + self.hash_name_to_role = {role['name']: role for role in Roles(api)} + + def has_cache(self, tagname): + return self.cache.has_key(tagname) - 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_type): self.cache[tagname]=tag_type + def get_cache(self, tagname): + return self.cache[tagname] - def locate_or_create_tag (self, tagname, category, description, roles): + def set_cache(self, tagname, tag_type): + self.cache[tagname] = tag_type + + def locate_or_create_tag(self, tagname, category, + description, roles, enforce=False): "search tag type from tagname & create if needed" # cached ? - if self.has_cache (tagname): + if self.has_cache(tagname): return self.get_cache(tagname) # search - tag_types = TagTypes (self.api, {'tagname':tagname}) + tag_types = TagTypes(self.api, {'tagname': tagname}) if tag_types: tag_type = tag_types[0] + # enforce should only be set by + # '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} - tag_type = TagType (self.api, tag_type_fields) + tag_type_fields = {'tagname': tagname, + 'category': category, + 'description': description} + tag_type = TagType(self.api, tag_type_fields) tag_type.sync() for role in roles: - try: - role_obj=Roles (self.api, role)[0] + 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 - print "Accessor.locate_or_create_tag: Could not add role %r to tag_type %s"%(role,tagname) - self.set_cache(tagname,tag_type) + 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 + def register_tag_locator(name, tag_locator): + Accessor.tag_locators[name] = tag_locator @staticmethod - def retrieve_tag_locator (name): + 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 + # 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): + def run_all_tag_locators(self): for (name, tag_locator) in Accessor.tag_locators.items(): - tag_locator(self) + tag_locator(self, enforce=True) #################### # make it a singleton so we can cache stuff in there over time -def AccessorSingleton (api): +def AccessorSingleton(api): if not Accessor._instance: Accessor._instance = Accessor(api) return Accessor._instance