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@@ -208,8 +208,49 @@ public class ActiveStandbyElector implements StatCallback, StringCallback {
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*/
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public ActiveStandbyElector(String zookeeperHostPorts,
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int zookeeperSessionTimeout, String parentZnodeName, List<ACL> acl,
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- List<ZKAuthInfo> authInfo,
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- ActiveStandbyElectorCallback app, int maxRetryNum) throws IOException,
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+ List<ZKAuthInfo> authInfo, ActiveStandbyElectorCallback app,
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+ int maxRetryNum) throws IOException, HadoopIllegalArgumentException,
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+ KeeperException {
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+ this(zookeeperHostPorts, zookeeperSessionTimeout, parentZnodeName, acl,
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+ authInfo, app, maxRetryNum, true);
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+ }
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+
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+ /**
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+ * Create a new ActiveStandbyElector object <br/>
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+ * The elector is created by providing to it the Zookeeper configuration, the
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+ * parent znode under which to create the znode and a reference to the
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+ * callback interface. <br/>
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+ * The parent znode name must be the same for all service instances and
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+ * different across services. <br/>
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+ * After the leader has been lost, a new leader will be elected after the
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+ * session timeout expires. Hence, the app must set this parameter based on
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+ * its needs for failure response time. The session timeout must be greater
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+ * than the Zookeeper disconnect timeout and is recommended to be 3X that
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+ * value to enable Zookeeper to retry transient disconnections. Setting a very
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+ * short session timeout may result in frequent transitions between active and
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+ * standby states during issues like network outages/GS pauses.
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+ *
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+ * @param zookeeperHostPorts
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+ * ZooKeeper hostPort for all ZooKeeper servers
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+ * @param zookeeperSessionTimeout
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+ * ZooKeeper session timeout
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+ * @param parentZnodeName
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+ * znode under which to create the lock
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+ * @param acl
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+ * ZooKeeper ACL's
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+ * @param authInfo a list of authentication credentials to add to the
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+ * ZK connection
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+ * @param app
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+ * reference to callback interface object
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+ * @param failFast
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+ * whether need to add the retry when establishing ZK connection.
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+ * @throws IOException
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+ * @throws HadoopIllegalArgumentException
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+ */
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+ public ActiveStandbyElector(String zookeeperHostPorts,
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+ int zookeeperSessionTimeout, String parentZnodeName, List<ACL> acl,
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+ List<ZKAuthInfo> authInfo, ActiveStandbyElectorCallback app,
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+ int maxRetryNum, boolean failFast) throws IOException,
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HadoopIllegalArgumentException, KeeperException {
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if (app == null || acl == null || parentZnodeName == null
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|| zookeeperHostPorts == null || zookeeperSessionTimeout <= 0) {
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@@ -225,8 +266,12 @@ public class ActiveStandbyElector implements StatCallback, StringCallback {
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zkBreadCrumbPath = znodeWorkingDir + "/" + BREADCRUMB_FILENAME;
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this.maxRetryNum = maxRetryNum;
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- // createConnection for future API calls
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- createConnection();
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+ // establish the ZK Connection for future API calls
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+ if (failFast) {
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+ createConnection();
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+ } else {
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+ reEstablishSession();
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+ }
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}
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/**
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Junping Du