[S4-85] Improve handling of ZK connection changes

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.5.0
• Fix Version/s: 0.5.0
• Assignee: Matthieu Morel
• Reporter: Daniel Gómez Ferro
• Created: 17/Jul/12 07:43
• Updated: 24/Jul/12 07:31
• Resolved: 24/Jul/12 07:31

Description

Currently we are handling ZK state changes a bit differently in two places.

org.apache.s4.comm.topology.AssignmentFromZK:

    @Override
    public void handleStateChanged(KeeperState state) throws Exception {
        this.state = state;
        if (!state.equals(KeeperState.SyncConnected)) {
            logger.warn("Session not connected for cluster [{}]: [{}]. Trying to reconnect", clusterName, state.name());
            zkClient.close();
            zkClient.connect(connectionTimeout, null);
            handleNewSession();
        }
    }

org.apache.s4.comm.topology.ClusterFromZK:

    @Override
    public void handleStateChanged(KeeperState state) throws Exception {
        this.state = state;
        if (!state.equals(KeeperState.SyncConnected)) {
            logger.warn("Session not connected for cluster [{}]: [{}]. Trying to reconnect", clusterName, state.name());
            zkClient.connect(connectionTimeout, null);
            handleNewSession();
        }
    }

In the first case we explicitly close the connection before trying to reconnect. Furthermore, I think we should only try to reconnect when the state is equals to KeeperState.Expired, since now we are closing the connection on a Disconnected event too.