apache / bookkeeper / 900

72%

push

jenkins

Track ZooKeeper errors as causes of ZKException

Descriptions of the changes in this PR:

### Motivation

Every time a problem with ZK arises you don't see it in the exception chain of the BKException (in this case ZKException) and you end up with errors like:
```
org.apache.bookkeeper.client.BKException$ZKException: Error while using ZooKeeper
        at org.apache.bookkeeper.client.SyncCallbackUtils.finish(SyncCallbackUtils.java:83)
        at org.apache.bookkeeper.client.SyncCallbackUtils$SyncAddCallback.addComplete(SyncCallbackUtils.java:251)
        at org.apache.bookkeeper.client.AsyncCallback$AddCallback.addCompleteWithLatency(AsyncCallback.java:91)
        at org.apache.bookkeeper.client.PendingAddOp.submitCallback(PendingAddOp.java:430)
        at org.apache.bookkeeper.client.LedgerHandle.errorOutPendingAdds(LedgerHandle.java:1784)
        at org.apache.bookkeeper.client.LedgerHandle$5.safeRun(LedgerHandle.java:574)
```

### Changes
Add a "cause" to every ZKException.

### Notes
There are very few places that cannot be fixed because they are still using the old callback based mechanism without CompletableFuture. Those points are not changed in order to make the patch simple but still useful.





Reviewers: Jia Zhai <zhaijia@apache.org>

This closes #2384 from eolivelli/fix/zkexception-chain

16 of 16 new or added lines in 3 files covered. (100.0%)

28589 of 39848 relevant lines covered (71.75%)

0.72 hits per line