[Curator] about isOwnedByCurrentThread() in InterProcessSemaphoreMutex

[Xu Cang <xc...@salesforce.com.INVALID>]

Hi Zookeeper/ Curator users and developers,
I have a question regarding this method: isOwnedByCurrentThread() in
InterProcessSemaphoreMutex in Curator

https://curator.apache.org/apidocs/org/apache/curator/framework/recipes/locks/InterProcessSemaphoreMutex.html#isAcquiredInThisProcess--

If scenario as below happens:

1. application using curator successfully acquired this mutex.
2. application lost connection to Zookeeper for several mins and lost ZK
connection.
3. After connection re-established, ZK state became RECONNECTED from LOST.

At this point, can I directly call isOwnedByCurrentThread() to determine if
this process has ownership of this mutex?
If yes, who is updating the 'lease' variable
https://github.com/apache/curator/blob/master/curator-recipes/src/main/java/org/apache/curator/framework/recipes/locks/InterProcessSemaphoreMutex.java#L78

If no, what's the recommended way to determine if this process has the
mutex's ownership or not?

Thank you in advance.

Xu

Re: [Curator] about isOwnedByCurrentThread() in InterProcessSemaphoreMutex

[Jordan Zimmerman <jo...@jordanzimmerman.com>]

As is stated in the Curator documentation (see: http://curator.apache.org/errors.html <http://curator.apache.org/errors.html>) you should assume that your locks are no longer valid when the connection is lost/suspended. If you get SUSPENDED or LOST you should interrupt your locks and consider them lost. For recipes like LeaderSelector, this is done for you (see: https://github.com/apache/curator/blob/master/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderSelectorListenerAdapter.java <https://github.com/apache/curator/blob/master/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderSelectorListenerAdapter.java>). 

-Jordan

> On Apr 3, 2019, at 7:17 PM, Xu Cang <xc...@salesforce.com.INVALID> wrote:
> 
> Hi Zookeeper/ Curator users and developers,
> I have a question regarding this method: isOwnedByCurrentThread() in
> InterProcessSemaphoreMutex in Curator
> 
> https://curator.apache.org/apidocs/org/apache/curator/framework/recipes/locks/InterProcessSemaphoreMutex.html#isAcquiredInThisProcess--
> 
> If scenario as below happens:
> 
> 1. application using curator successfully acquired this mutex.
> 2. application lost connection to Zookeeper for several mins and lost ZK
> connection.
> 3. After connection re-established, ZK state became RECONNECTED from LOST.
> 
> At this point, can I directly call isOwnedByCurrentThread() to determine if
> this process has ownership of this mutex?
> If yes, who is updating the 'lease' variable
> https://github.com/apache/curator/blob/master/curator-recipes/src/main/java/org/apache/curator/framework/recipes/locks/InterProcessSemaphoreMutex.java#L78
> 
> If no, what's the recommended way to determine if this process has the
> mutex's ownership or not?
> 
> Thank you in advance.
> 
> Xu