private boolean updateCurrent(LeaderElection req) {
boolean isNew = false;
if (current == null) {
current = new ElectionState();
isNew = true;
} else {
if (req.getExpires() > current.maxDuration) {
isNew = false; // If this election was started after the current election, dont do anything!
logger.info("Ignoring this election - older election already in progress! Not voting!");
return isNew;
} else {
isNew = true;
}
}
if (req.getCandidateId() == this.nodeId) {
// logger.info("Updating election details in RAFT Election");
isNew = false;
}
current.electionID = req.getElectId();
current.candidate = req.getCandidateId();
current.desc = req.getDesc();
current.maxDuration = req.getExpires();
current.startedOn = System.currentTimeMillis();
current.state = req.getAction();
current.id = -1; // TODO me or sender?
current.active = true;
return isNew;
}
/** @param args */
public void processRequest(Management mgmt) {
if (!mgmt.hasElection()) return;
LeaderElection req = mgmt.getElection();
// when a new node joins the network it will want to know who the leader
// is - we kind of ram this request-response in the process request
// though there has to be a better place for it
if (req.getAction().getNumber() == LeaderElection.ElectAction.WHOISTHELEADER_VALUE) {
respondToWhoIsTheLeader(mgmt);
return;
} else if (req.getAction().getNumber() == LeaderElection.ElectAction.THELEADERIS_VALUE) {
logger.info(
"Node "
+ conf.getNodeId()
+ " got an answer on who the leader is. Its Node "
+ req.getCandidateId());
this.leaderNode = req.getCandidateId();
this.termId = req.getTermId();
// the current term id
// TODO Last log index to be synced
return;
}
// else fall through to an election
// if the time has expired, an election is initiated.
if (req.hasExpires()) {
long ct = System.currentTimeMillis();
if (ct > req.getExpires()) {
// ran out of time so the election is over
if (election != null) election.clear();
return;
}
}
Management rtn = electionInstance().process(mgmt);
if (rtn != null) ConnectionManager.broadcast(rtn);
}
/*
* (non-Javadoc)
*
* @see poke.server.election.Election#process(eye.Comm.LeaderElection)
*
* @return The Management instance returned represents the message to send
* on. If null, no action is required. Not a great choice to convey to the
* caller; can be improved upon easily.
*/
@Override
public Management process(Management mgmt) {
if (!mgmt.hasElection()) return null;
LeaderElection req = mgmt.getElection();
if (req.getExpires() <= System.currentTimeMillis()) {
// election has expired without a conclusion?
}
Management rtn = null;
if (req.getAction().getNumber() == ElectAction.DECLAREELECTION_VALUE) {
// an election is declared!
// required to eliminate duplicate messages - on a declaration,
// should not happen if the network does not have cycles
List<VectorClock> rtes = mgmt.getHeader().getPathList();
for (VectorClock rp : rtes) {
if (rp.getNodeId() == this.nodeId) {
// message has already been sent to me, don't use and
// forward
return null;
}
}
// I got here because the election is unknown to me
// this 'if debug is on' should cover the below dozen or so
// println()s. It is here to help with seeing when an election
// occurs.
if (logger.isDebugEnabled()) {}
System.out.println("\n\n*********************************************************");
System.out.println(" RAFT ELECTION: Election declared");
System.out.println(" Election ID: " + req.getElectId());
System.out.println(" Rcv from: Node " + mgmt.getHeader().getOriginator());
System.out.println(" Expires: " + new Date(req.getExpires()));
System.out.println(" Nominates: Node " + req.getCandidateId());
System.out.println(" Desc: " + req.getDesc());
System.out.print(" Routing tbl: [");
for (VectorClock rp : rtes)
System.out.print(
"Node " + rp.getNodeId() + " (" + rp.getVersion() + "," + rp.getTime() + "), ");
System.out.println("]");
System.out.println("*********************************************************\n\n");
// sync master IDs to current election
ElectionIDGenerator.setMasterID(req.getElectId());
/**
* a new election can be declared over an existing election.
*
* <p>TODO need to have an monotonically increasing ID that we can test
*/
boolean isNew = updateCurrent(req);
rtn = castVote(mgmt, isNew);
} else if (req.getAction().getNumber() == ElectAction.DECLAREVOID_VALUE) {
// no one was elected, I am dropping into standby mode
logger.info("TODO: no one was elected, I am dropping into standby mode");
this.clear();
notify(false, null);
} else if (req.getAction().getNumber() == ElectAction.DECLAREWINNER_VALUE) {
// some node declared itself the leader
logger.info(
"Election "
+ req.getElectId()
+ ": Node "
+ req.getCandidateId()
+ " is declared the leader");
updateCurrent(mgmt.getElection());
current.active = false; // it's over
notify(true, req.getCandidateId());
} else if (req.getAction().getNumber() == ElectAction.ABSTAIN_VALUE) {
// for some reason, a node declines to vote - therefore, do nothing
} else if (req.getAction().getNumber() == ElectAction.NOMINATE_VALUE) {
boolean isNew = updateCurrent(mgmt.getElection());
rtn = castVote(mgmt, isNew);
} else {
// this is me!
}
return rtn;
}