From 49b3fdacf04c3746e56d754a2fc0178c23c2259b Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Thu, 18 Mar 2010 16:46:54 +0100
Subject: [PATCH] Extend ConfdFilterCallback with consistency checks
Note that users of the callback will have to manually check the
attribute.
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>
---
lib/confd/client.py | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/lib/confd/client.py b/lib/confd/client.py
index dfbc65063..71b510435 100644
--- a/lib/confd/client.py
+++ b/lib/confd/client.py
@@ -347,6 +347,12 @@ class ConfdClientRequest(objects.ConfdRequest):
class ConfdFilterCallback:
"""Callback that calls another callback, but filters duplicate results.
+ @ivar consistent: a dictionary indexed by salt; for each salt, if
+ all responses ware identical, this will be True; this is the
+ expected state on a healthy cluster; on inconsistent or
+ partitioned clusters, this might be False, if we see answers
+ with the same serial but different contents
+
"""
def __init__(self, callback, logger=None):
"""Constructor for ConfdFilterCallback
@@ -364,6 +370,7 @@ class ConfdFilterCallback:
self._logger = logger
# answers contains a dict of salt -> answer
self._answers = {}
+ self.consistent = {}
def _LogFilter(self, salt, new_reply, old_reply):
if not self._logger:
@@ -388,6 +395,8 @@ class ConfdFilterCallback:
# if we have no answer we have received none, before the expiration.
if up.salt in self._answers:
del self._answers[up.salt]
+ if up.salt in self.consistent:
+ del self.consistent[up.salt]
def _HandleReply(self, up):
"""Handle a single confd reply, and decide whether to filter it.
@@ -399,6 +408,8 @@ class ConfdFilterCallback:
"""
filter_upcall = False
salt = up.salt
+ if salt not in self.consistent:
+ self.consistent[salt] = True
if salt not in self._answers:
# first answer for a query (don't filter, and record)
self._answers[salt] = up.server_reply
@@ -413,6 +424,8 @@ class ConfdFilterCallback:
# else: different content, pass up a second answer
else:
# older or same-version answer (duplicate or outdated, filter)
+ if up.server_reply.answer != self._answers[salt].answer:
+ self.consistent[salt] = False
filter_upcall = True
self._LogFilter(salt, up.server_reply, self._answers[salt])
--
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