Merge branch 'master' into exp2

[sfa.git] / sfa / util / api.py

diff --git a/sfa/util/api.py b/sfa/util/api.py
index 4b94208..eeb3d6a 100644 (file)
--- a/sfa/util/api.py
+++ b/sfa/util/api.py
@@ -1,24 +1,20 @@
 #
 # SFA XML-RPC and SOAP interfaces
 #
-### $Id$
-### $URL$
-#
 
 import sys
 import os
 import traceback
 import string
 import xmlrpclib
-
+import sfa.util.xmlrpcprotocol as xmlrpcprotocol
+from sfa.util.sfalogging import logger
 from sfa.trust.auth import Auth
 from sfa.util.config import *
 from sfa.util.faults import *
-from sfa.util.debug import *
+from sfa.util.cache import Cache
 from sfa.trust.credential import *
 from sfa.trust.certificate import *
-from sfa.util.namespace import *
-from sfa.util.sfalogging import *
 
 # See "2.2 Characters" in the XML specification:
 #
@@ -95,14 +91,34 @@ def import_deep(name):
         mod = getattr(mod, comp)
     return mod
 
+class ManagerWrapper:
+    """
+    This class acts as a wrapper around an SFA interface manager module, but
+    can be used with any python module. The purpose of this class is raise a 
+    SfaNotImplemented exception if the a someone attepmts to use an attribute 
+    (could be a callable) thats not available in the library by checking the
+    library using hasattr. This helps to communicate better errors messages 
+    to the users and developers in the event that a specifiec operation 
+    is not implemented by a libarary and will generally be more helpful than
+    the standard AttributeError         
+    """
+    def __init__(self, manager, interface):
+        self.manager = manager
+        self.interface = interface
+        
+    def __getattr__(self, method):
+        
+        if not hasattr(self.manager, method):
+            raise SfaNotImplemented(method, self.interface)
+        return getattr(self.manager, method)
+        
 class BaseAPI:
 
-    cache = None
     protocol = None
   
     def __init__(self, config = "/etc/sfa/sfa_config.py", encoding = "utf-8", 
                  methods='sfa.methods', peer_cert = None, interface = None, 
-                 key_file = None, cert_file = None, cache = cache):
+                 key_file = None, cert_file = None, cache = None):
 
         self.encoding = encoding
         
@@ -113,7 +129,6 @@ class BaseAPI:
         # Better just be documenting the API
         if config is None:
             return
-        
         # Load configuration
         self.config = Config(config)
         self.auth = Auth(peer_cert)
@@ -124,21 +139,23 @@ class BaseAPI:
         self.cert_file = cert_file
         self.cert = Certificate(filename=self.cert_file)
         self.cache = cache
+        if self.cache is None:
+            self.cache = Cache()
         self.credential = None
         self.source = None 
         self.time_format = "%Y-%m-%d %H:%M:%S"
-        self.logger=get_sfa_logger()
-        
+        self.logger = logger
+ 
         # load registries
         from sfa.server.registry import Registries
-        self.registries = Registries(self) 
+        self.registries = Registries() 
 
         # load aggregates
         from sfa.server.aggregate import Aggregates
-        self.aggregates = Aggregates(self)
+        self.aggregates = Aggregates()
 
 
-    def get_manager(self, manager_base = 'sfa.managers'):
+    def get_interface_manager(self, manager_base = 'sfa.managers'):
         """
         Returns the appropriate manager module for this interface.
         Modules are usually found in sfa/managers/
@@ -158,8 +175,11 @@ class BaseAPI:
             manager_module = manager_base + ".component_manager_%s" % mgr_type
         else:
             raise SfaAPIError("No manager for interface: %s" % self.interface)  
-        manager = __import__(manager_module, fromlist=[manager_base])   
- 
+        manager = __import__(manager_module, fromlist=[manager_base])
+        # this isnt necessary but will help to produce better error messages
+        # if someone tries to access an operation this manager doesn't implement  
+        manager = ManagerWrapper(manager, self.interface)
+
         return manager
 
     def callable(self, method):
@@ -219,7 +239,7 @@ class BaseAPI:
         except SfaFault, fault:
             result = fault 
         except Exception, fault:
-            traceback.print_exc(file = log)
+            logger.log_exc("BaseAPI.handle has caught Exception")
             result = SfaAPIError(fault)
 
 
@@ -247,3 +267,14 @@ class BaseAPI:
                 raise result 
             
         return response
+
+    def get_cached_server_version(self, server):
+        cache_key = server.url + "-version"
+        server_version = None
+        if self.cache:
+            server_version = self.cache.get(cache_key)
+        if not server_version:
+            server_version = server.GetVersion()
+            # cache version for 24 hours
+            self.cache.add(cache_key, server_version, ttl= 60*60*24)
+        return server_version