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https://issues.apache.org/jira/browse/CURATOR-164?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14505316#comment-14505316
 ] 

ASF GitHub Bot commented on CURATOR-164:
----------------------------------------

Github user Randgalt commented on a diff in the pull request:

    https://github.com/apache/curator/pull/72#discussion_r28801137
  
    --- Diff: 
curator-x-discovery/src/main/java/org/apache/curator/x/discovery/details/ServiceDiscoveryImpl.java
 ---
    @@ -207,9 +207,15 @@ protected void     
internalRegisterService(ServiceInstance<T> service) throws Ex
             {
                 try
                 {
    -                CreateMode      mode = (service.getServiceType() == 
ServiceType.DYNAMIC) ? CreateMode.EPHEMERAL : CreateMode.PERSISTENT;
    -                
client.create().creatingParentsIfNeeded().withMode(mode).forPath(path, bytes);
    -                isDone = true;
    +                synchronized(service) {
    +                    // Check that the service didn't get deleted while we 
were reconnecting
    +                    if (services.containsKey(service.getId()))
    --- End diff --
    
    Why is this needed? The test passes without this and logically it seems 
unnecessary.


> curator-x-discovery: unregisterService is not guaranteed to remove the 
> service, due to reconnectListener concurrency issue
> --------------------------------------------------------------------------------------------------------------------------
>
>                 Key: CURATOR-164
>                 URL: https://issues.apache.org/jira/browse/CURATOR-164
>             Project: Apache Curator
>          Issue Type: Bug
>          Components: Framework
>    Affects Versions: 2.7.0
>            Reporter: Rasmus Berg Palm
>            Assignee: Jordan Zimmerman
>            Priority: Critical
>             Fix For: 2.8.0
>
>
> In ServiceDiscoveryImpl:
> When unregistering a service, the reconnect listener might fire while 
> deleting the path.
> This can cause a condition where the delete finishes successfully, the 
> service is removed from services, and then the reRegisterServices completes 
> successfully and the service is added back in ZK and in services, end result 
> being that the service was not removed, even though unregisterService did not 
> throw any exceptions. 
> Essentially the use of the internal 'services' cache makes for a nightmare of 
> concurrency issues. I put this as critical as the library it's really not 
> usable IMO.



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