[trigger] MetaService en place, et amélioration du débug

gestion/trigger/services/service.py

@@ -6,11 +6,65 @@ This module provides a basic service class to other services. It should *NOT*
 be referenced in configuration of trigger.
 """
 
+import collections
+
+import cranslib.clogger as clogger
+import gestion.config.trigger as trigger_config
+from gestion.trigger.host import TriggerFactory
+
+logger = clogger.CLogger("trigger", "service", "debug", trigger_config.debug)
+
+class MetaService(type):
+    """Metaclass designed to handle all services.
+
+    """
+
+    def __new__(mcs, cname, cpar, cattrs):
+        """Method producing the new class itself
+        At first, I wanted to put the changes_trigger modification in __new__,
+        using direct modification of cattrs['changes_trigger'] by pointing the
+        required methods (classmethods). The problem was that these methods were
+        bound at the return of type.__new__, for a reason I could not exactly
+        explain.
+
+        I found a workaround using __init__, so the point would be to remove
+        __new__, and directly use type.__new__, but this comment seems useful,
+        so __new__ will survive.
+
+        """
+        return super(MetaService, mcs).__new__(mcs, cname, cpar, cattrs)
+
+    def __init__(cls, cname, cpar, cattrs):
+        """Used to register the generated classes in TriggerFactory, and modify the behavior of
+        changes_trigger by pointing functions instead of their names. This allows to cancel any
+        positional requirement in class definition.
+
+        Do NEVER return something in __init__ function.
+
+        """
+        if not cname == "BasicService":
+            TriggerFactory.register(cname.lower(), cls)
+        changes_trigger = collections.defaultdict(list)
+        # I love getattr
+        text_changes_trigger = getattr(cls, "changes_trigger", {})
+        for (ldap_attr_name, funcs_name) in text_changes_trigger.items():
+            for func_name in funcs_name:
+                # I really love getattr.
+                get = getattr(cls, func_name, None)
+                if get is None:
+                    logger.critical("Fatal, bad function (%r) reference in %r.", func_name, cname)
+                    continue
+                changes_trigger[ldap_attr_name].append(get)
+        setattr(cls, "changes_trigger", changes_trigger)
+        super(MetaService, cls).__init__(cname, cpar, cattrs)
+
 class BasicService(object):
     """Basic service handler. Other services should inherit fron this one.
 
     """
 
+    __metaclass__ = MetaService
+
     changes_trigger = {}
 
     @classmethod