ERP5OOoDocument: use conversion server that has the most chance to work

Until know, in the preference we defined list of uri for conversion
server, and then we were trying always in the order defined in the
preference. But this is not optimal, when a server start to fail, it's
better to try using another one. So sort list of uri in such a way to
use first server having the most chance to work.

product/ERP5OOo/Document/OOoDocument.py

@@ -49,6 +49,7 @@ from functools import partial
 from Products.ERP5.mixin.base_convertable import BaseConvertableFileMixin
 from Products.ERP5.mixin.text_convertable import TextConvertableMixin
 from Products.ERP5.mixin.extensible_traversable import OOoDocumentExtensibleTraversableMixin
+from DateTime import DateTime
 
 # connection plugins
 from Products.ERP5Type.ConnectionPlugin.TimeoutTransport import TimeoutTransport
@@ -61,6 +62,10 @@ EMBEDDED_FORMAT = '_embedded'
 OOO_SERVER_PROXY_TIMEOUT = 360
 OOO_SERVER_RETRY = 0
 
+# store time (as int) where we had last failure in order
+# to try using proxy server that worked the most recently
+global_server_proxy_uri_failure_time = {}
+
 class OOoServerProxy():
   """
   xmlrpc-like ServerProxy object adapted for OOo conversion server
@@ -95,7 +100,8 @@ class OOoServerProxy():
 
       transport = TimeoutTransport(timeout=timeout, scheme=scheme)
       
-      self._serverproxy_list.append(ServerProxy(uri, allow_none=True, transport=transport))
+      self._serverproxy_list.append((uri, ServerProxy(uri, allow_none=True, transport=transport)))
+
   def _proxy_function(self, func_name, *args, **kw):
     result_error_set_list = []
     protocol_error_list = []
@@ -103,10 +109,13 @@ class OOoServerProxy():
     fault_error_list = []
     count = 0
     serverproxy_list = self._serverproxy_list
+    # we have list of tuple (uri, ServerProxy()). Sort by uri having oldest failure
+    serverproxy_list.sort(key=lambda x: global_server_proxy_uri_failure_time.get(x[0], 0))
     while True:
       retry_server_list = []
-      for server_proxy in serverproxy_list:
+      for uri, server_proxy in serverproxy_list:
         func = getattr(server_proxy, func_name)
+        failure = True
         try:
           # Cloudooo return result in (200 or 402, dict(), '') format or just based type
           # 402 for error and 200 for ok
@@ -114,21 +123,21 @@ class OOoServerProxy():
         except SocketError, e:
           message = 'Socket Error: %s' % (repr(e) or 'undefined.')
           socket_error_list.append(message)
-          retry_server_list.append(server_proxy)
-          continue
+          retry_server_list.append((uri, server_proxy))
         except ProtocolError, e:
           # Network issue
           message = "%s: %s %s" % (e.url, e.errcode, e.errmsg)
           if e.errcode == -1:
             message = "%s: Connection refused" % (e.url)
           protocol_error_list.append(message)
-          retry_server_list.append(server_proxy)
-          continue
+          retry_server_list.append((uri, server_proxy))
         except Fault, e:
           # Return not supported data types
           fault_error_list.append(e)
-          continue
+        else:
+          failure = False
 
+        if not(failure):
           try:
             response_code, response_dict, response_message = result_set
           except ValueError:
@@ -141,6 +150,10 @@ class OOoServerProxy():
             # If error, try next one
             result_error_set_list.append(result_set)
 
+        # Still there ? this means we had no result,
+        # avoid using same server again
+        global_server_proxy_uri_failure_time[uri] = int(DateTime())
+
       # All servers are failed
       if count == self._ooo_server_retry or len(retry_server_list) == 0:
         break