void createClient() throws Exception {
PathBasedZkSerializer zkSerializer =
ChainedPathZkSerializer.builder(new ZNRecordStreamingSerializer()).build();
_zkclient =
new ZkClient(
_zkAddress, _sessionTimeout, ZkClient.DEFAULT_CONNECTION_TIMEOUT, zkSerializer);
_baseDataAccessor = createBaseDataAccessor();
_dataAccessor = new ZKHelixDataAccessor(_clusterName, _instanceType, _baseDataAccessor);
_configAccessor = new ConfigAccessor(_zkclient);
int retryCount = 0;
_zkclient.subscribeStateChanges(this);
while (retryCount < 3) {
try {
_zkclient.waitUntilConnected(_sessionTimeout, TimeUnit.MILLISECONDS);
handleStateChanged(KeeperState.SyncConnected);
handleNewSession();
break;
} catch (HelixException e) {
LOG.error("fail to createClient.", e);
throw e;
} catch (Exception e) {
retryCount++;
LOG.error("fail to createClient. retry " + retryCount, e);
if (retryCount == 3) {
throw e;
}
}
}
}
/**
* wait until we get a non-zero session-id. note that we might lose zkconnection right after we
* read session-id. but it's ok to get stale session-id and we will have another
* handle-new-session callback to correct this.
*/
void waitUntilConnected() {
boolean isConnected;
do {
isConnected =
_zkclient.waitUntilConnected(ZkClient.DEFAULT_CONNECTION_TIMEOUT, TimeUnit.MILLISECONDS);
if (!isConnected) {
LOG.error(
"fail to connect zkserver: "
+ _zkAddress
+ " in "
+ ZkClient.DEFAULT_CONNECTION_TIMEOUT
+ "ms. expiredSessionId: "
+ _sessionId
+ ", clusterName: "
+ _clusterName);
continue;
}
ZkConnection zkConnection = ((ZkConnection) _zkclient.getConnection());
_sessionId = Long.toHexString(zkConnection.getZookeeper().getSessionId());
/**
* at the time we read session-id, zkconnection might be lost again wait until we get a
* non-zero session-id
*/
} while ("0".equals(_sessionId));
LOG.info(
"Handling new session, session id: "
+ _sessionId
+ ", instance: "
+ _instanceName
+ ", instanceTye: "
+ _instanceType
+ ", cluster: "
+ _clusterName
+ ", zkconnection: "
+ ((ZkConnection) _zkclient.getConnection()).getZookeeper());
}
