curator-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Scott Blum <dragonsi...@gmail.com>
Subject Re: PLEASE REVIEW - Major re-work of Watcher wrappers
Date Fri, 05 Feb 2016 17:22:05 GMT
Okay, so I looked into this for a bit, and I hit kind of a wall.  I think
there is a legit bug/race in TreeCache, and the following patch *should*
remedy:

diff --git
a/curator-recipes/src/main/java/org/apache/curator/framework/recipes/cache/TreeCache.java
b/curator-recipes/src/main/java/org/apache/curator/framework/recipes/cache/TreeCache.java
index df4403c..a4a022b 100644
---
a/curator-recipes/src/main/java/org/apache/curator/framework/recipes/cache/TreeCache.java
+++
b/curator-recipes/src/main/java/org/apache/curator/framework/recipes/cache/TreeCache.java
@@ -303,7 +303,6 @@ public class TreeCache implements Closeable
         void wasDeleted() throws Exception
         {
             ChildData oldChildData = childData.getAndSet(null);
-
 client.watches().remove(this).ofType(WatcherType.Any).locally().inBackground().forPath(path);
             ConcurrentMap<String, TreeNode> childMap =
children.getAndSet(null);
             if ( childMap != null )
             {
@@ -807,8 +806,16 @@ public class TreeCache implements Closeable
         case RECONNECTED:
             try
             {
+                outstandingOps.incrementAndGet();
                 root.wasReconnected();
                 publishEvent(TreeCacheEvent.Type.CONNECTION_RECONNECTED);
+                if ( outstandingOps.decrementAndGet() == 0 )
+                {
+                    if ( isInitialized.compareAndSet(false, true) )
+                    {
+                        publishEvent(TreeCacheEvent.Type.INITIALIZED);
+                    }
+                }
             }
             catch ( Exception e )
             {

That should guarantee that the initialized event gets deferred until all
outstanding refreshes finish.. but it's not.  Something seems to have
changed under the hood in how background events are getting sent to
TreeCache, and I don't really understand it yet.  And running the debugger
seems to affect the timing, like something racy is going on. :(


On Fri, Feb 5, 2016 at 11:57 AM, Scott Blum <dragonsinth@gmail.com> wrote:

> Ok, that is kind of weird.  I'll take a look.
>
> On Fri, Feb 5, 2016 at 4:58 AM, Jordan Zimmerman <
> jordan@jordanzimmerman.com> wrote:
>
>> No, sorry. The last few lines of the test currently are:
>>
>>
>> assertEvent(TreeCacheEvent.Type.NODE_REMOVED, "/test/me", "data".getBytes());
>> assertEvent(TreeCacheEvent.Type.INITIALIZED);
>>
>> This fails. But, if I switch them it works:
>>
>> assertEvent(TreeCacheEvent.Type.INITIALIZED);
>>
>> assertEvent(TreeCacheEvent.Type.NODE_REMOVED, "/test/me", "data".getBytes());
>>
>> On Feb 5, 2016, at 2:57 AM, Scott Blum <dragonsinth@gmail.com> wrote:
>>
>> So you end up with 2 initialized events?
>>
>> You mean this?
>>
>>          assertEvent(TreeCacheEvent.Type.CONNECTION_RECONNECTED);
>> +        assertEvent(TreeCacheEvent.Type.INITIALIZED);
>>          assertEvent(TreeCacheEvent.Type.NODE_REMOVED, "/test/me",
>> "data".getBytes());
>>          assertEvent(TreeCacheEvent.Type.INITIALIZED);
>>
>> Seems weird if there are two, but I can help look.
>>
>> On Thu, Feb 4, 2016 at 10:48 PM, Jordan Zimmerman <
>> jordan@jordanzimmerman.com> wrote:
>>
>>> Hey Scott,
>>>
>>> In this branch, TestTreeCache.testKilledSession() is failing at:
>>>
>>>         assertEvent(TreeCacheEvent.Type.NODE_REMOVED, "/test/me",
>>> "data".getBytes());
>>>
>>> However, if I change the two asserts to:
>>>
>>>         assertEvent(TreeCacheEvent.Type.INITIALIZED);
>>>         assertEvent(TreeCacheEvent.Type.NODE_REMOVED, "/test/me",
>>> "data".getBytes());
>>>
>>> it works. Does that make any sense?
>>>
>>> -Jordan
>>>
>>> > On Feb 4, 2016, at 9:23 PM, Jordan Zimmerman <
>>> jordan@jordanzimmerman.com> wrote:
>>> >
>>> > Devs,
>>> >
>>> > In trying to fix the bad log message "Failed to find watcher” (which
>>> turns out to be a ZK client issue), I realize that the NamespaceWatcher and
>>> WatcherWrapper stuff could be improved. I’m still working on getting all
>>> tests to pass but I’d appreciate more sets of eyes on this change. Please
>>> review carefully if you can.
>>> >
>>> > https://github.com/apache/curator/pull/131
>>> >
>>> > -Jordan
>>>
>>>
>>
>>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message