Major Description
While working on ZOOKEEPER-2014, I noticed a discrepancy between Java and C client regarding the error codes definition. There is a
ZRWSERVERFOUND = -122
definition in C client which is not present in Java client's KeeperException.Code definitions.
This discrepancy was introduced by ZOOKEEPER-827, where the C client logic was simulating the Java client's logic when doing a read/write server search while client is in read only mode. Once client finds a valid read/write server, client will try to disconnect and reconnect with this read/write server, as we always prefer r/w server in ro mode. The way Java client is doing this disconnect/reconnect process is by throwing a RWServerFoundException (instead of a KeeperException) to set the client in disconnected state, then wait for client reconnect with r/w server address set before throwing the exception. C client did similar but instead of having an explicitly disconnect / clean up routine, the client was relying on handle_error to do the job where ZRWSERVERFOUND was introduced.
I propose we remove ZRWSERVERFOUND error code from C client and use an explicit routine instead of handle_error when we do r/w server search in C client for two reasons:
- ZRWSERVERFOUND is not something ZK client users would need to know. It's a pure implementation detail that's used to alter the connection state of the client, and ZK client users have no desire nor need to handle such errors, as R/W server scanning and connect is handled transparently by ZK client library.
- To maintain consistency between Java and C client regarding error codes definition. Without removing this from C client, we would need to replace RWServerFoundException in Java client with a new KeeperException, and again with the reason mentioned above, we don't need a KeeperException for this because such implementation detail does not have to be exposed to end users (unless, we provided alternative for users to opt-out automate R/W server switching when in read only mode which we don't.).
Attachments
Attachments
Issue Links
- links to
