GitHub user jiajunwang opened a pull request:
https://github.com/apache/helix/pull/103
Fix disconnected zkConnection issue.
One issue is found that when zkConnection is using an invalid zookeeper
object (null), the callers will get NPE error.
Affected Helix components are ZKHelixManager, ZkHelixPropertyStore, and
other ZK related classes.
For fixing this issue:
1. Override retryUntilConnected() in Helix ZkClient to check the connection
before trigger callbacks. This will prevent NPE. But the user will still need
to try-catch IllegalStateException and re-create a ZkClient if necessary.
2. For ZKHelixManager, implement handleSessionEstablishmentError to retry
establishing a new connection. If the retry fails, Helix invokes a user
registered state handler.
3. Add unit test for simulating connection error and test if error handler
can recover the connection or trigger user registered callback.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/jiajunwang/helix zkFix
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/helix/pull/103.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #103
----
commit 3064c40556afa5afa71c102708c519ffa2ba7b8c
Author: Jiajun Wang <jjw...@linkedin.com>
Date: 2017-07-25T23:50:22Z
Fix disconnected zkConnection issue.
One issue is found that when zkConnection may be using an invalid zookeeper
object (null). And related calls will get NPE error.
Affected Helix components are ZKHelixManager, ZkHelixPropertyStore and
other zk related classes.
For fixing this issue:
1. Override retryUntilConnected() in Helix ZkClient to check the connection
before trigger callbacks. This will prevent NPE. But user will still need to
try-catch IllegalStateException, and re-create a ZkClient if necessary.
2. For ZKHelixManager, implement handleSessionEstablishmentError to retry
establishing a new connection. If retry fails, Helix invokes a user registered
state handler.
3. Add unit test for simulating connection error and test if error handler
can recover the connection or trigger user registered callback.
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