/** 寻找对应的leader */
public Vote lookForLeader() throws InterruptedException {
try {
self.jmxLeaderElectionBean = new LeaderElectionBean();
MBeanRegistry.getInstance().register(self.jmxLeaderElectionBean, self.jmxLocalPeerBean);
} catch (Exception e) {
LOG.warn("Failed to register with JMX", e);
self.jmxLeaderElectionBean = null;
}
if (self.start_fle == 0) {
self.start_fle = System.currentTimeMillis();
}
try {
HashMap<Long, Vote> recvset = new HashMap<Long, Vote>();
HashMap<Long, Vote> outofelection = new HashMap<Long, Vote>();
int notTimeout = finalizeWait;
synchronized (this) {
logicalclock++;
updateProposal(getInitId(), getInitLastLoggedZxid(), getPeerEpoch());
}
LOG.info(
"New election. My id = "
+ self.getId()
+ ", proposed zxid=0x"
+ Long.toHexString(proposedZxid));
sendNotifications();
/*
* Loop in which we exchange notifications until we find a leader
*/
while ((self.getPeerState() == ServerState.LOOKING) && (!stop)) {
/*
* Remove next notification from queue, times out after 2 times
* the termination time
*/
Notification n = recvqueue.poll(notTimeout, TimeUnit.MILLISECONDS);
/*
* Sends more notifications if haven't received enough.
* Otherwise processes new notification.
*/
if (n == null) {
if (manager.haveDelivered()) {
sendNotifications();
} else {
manager.connectAll();
}
/*
* Exponential backoff
*/
int tmpTimeOut = notTimeout * 2;
notTimeout =
(tmpTimeOut < maxNotificationInterval ? tmpTimeOut : maxNotificationInterval);
LOG.info("Notification time out: " + notTimeout);
} else if (self.getVotingView().containsKey(n.sid)) {
/*
* Only proceed if the vote comes from a replica in the
* voting view.
*/
switch (n.state) {
case LOOKING:
// If notification > current, replace and send messages
// out
if (n.electionEpoch > logicalclock) {
logicalclock = n.electionEpoch;
recvset.clear();
if (totalOrderPredicate(
n.leader,
n.zxid,
n.peerEpoch,
getInitId(),
getInitLastLoggedZxid(),
getPeerEpoch())) {
updateProposal(n.leader, n.zxid, n.peerEpoch);
} else {
updateProposal(getInitId(), getInitLastLoggedZxid(), getPeerEpoch());
}
sendNotifications();
} else if (n.electionEpoch < logicalclock) {
if (LOG.isDebugEnabled()) {
LOG.debug(
"Notification election epoch is smaller than logicalclock. n.electionEpoch = 0x"
+ Long.toHexString(n.electionEpoch)
+ ", logicalclock=0x"
+ Long.toHexString(logicalclock));
}
break;
} else if (totalOrderPredicate(
n.leader, n.zxid, n.peerEpoch, proposedLeader, proposedZxid, proposedEpoch)) {
updateProposal(n.leader, n.zxid, n.peerEpoch);
sendNotifications();
}
if (LOG.isDebugEnabled()) {
LOG.debug(
"Adding vote: from="
+ n.sid
+ ", proposed leader="
+ n.leader
+ ", proposed zxid=0x"
+ Long.toHexString(n.zxid)
+ ", proposed election epoch=0x"
+ Long.toHexString(n.electionEpoch));
}
recvset.put(n.sid, new Vote(n.leader, n.zxid, n.electionEpoch, n.peerEpoch));
if (termPredicate(
recvset, new Vote(proposedLeader, proposedZxid, logicalclock, proposedEpoch))) {
// Verify if there is any change in the proposed
// leader
while ((n = recvqueue.poll(finalizeWait, TimeUnit.MILLISECONDS)) != null) {
if (totalOrderPredicate(
n.leader, n.zxid, n.peerEpoch, proposedLeader, proposedZxid, proposedEpoch)) {
recvqueue.put(n);
break;
}
}
/*
* This predicate is true once we don't read any new
* relevant message from the reception queue
*/
if (n == null) {
self.setPeerState(
(proposedLeader == self.getId()) ? ServerState.LEADING : learningState());
Vote endVote =
new Vote(proposedLeader, proposedZxid, logicalclock, proposedEpoch);
leaveInstance(endVote);
return endVote;
}
}
break;
case OBSERVING:
LOG.debug("Notification from observer: " + n.sid);
break;
case FOLLOWING:
case LEADING:
/*
* Consider all notifications from the same epoch
* together.
*/
if (n.electionEpoch == logicalclock) {
recvset.put(n.sid, new Vote(n.leader, n.zxid, n.electionEpoch, n.peerEpoch));
if (ooePredicate(recvset, outofelection, n)) {
self.setPeerState(
(n.leader == self.getId()) ? ServerState.LEADING : learningState());
Vote endVote = new Vote(n.leader, n.zxid, n.electionEpoch, n.peerEpoch);
leaveInstance(endVote);
return endVote;
}
}
/*
* Before joining an established ensemble, verify a
* majority is following the same leader.
*/
outofelection.put(
n.sid,
new Vote(n.version, n.leader, n.zxid, n.electionEpoch, n.peerEpoch, n.state));
if (ooePredicate(outofelection, outofelection, n)) {
synchronized (this) {
logicalclock = n.electionEpoch;
self.setPeerState(
(n.leader == self.getId()) ? ServerState.LEADING : learningState());
}
Vote endVote = new Vote(n.leader, n.zxid, n.electionEpoch, n.peerEpoch);
leaveInstance(endVote);
return endVote;
}
break;
default:
LOG.warn("Notification state unrecognized: {} (n.state), {} (n.sid)", n.state, n.sid);
break;
}
} else {
LOG.warn("Ignoring notification from non-cluster member " + n.sid);
}
}
return null;
} finally {
try {
if (self.jmxLeaderElectionBean != null) {
MBeanRegistry.getInstance().unregister(self.jmxLeaderElectionBean);
}
} catch (Exception e) {
LOG.warn("Failed to unregister with JMX", e);
}
self.jmxLeaderElectionBean = null;
}
}
