Examples with SnapshotInfo org.apache.ratis.statemachine.SnapshotInfo used on opensource projects

Example 1 with SnapshotInfo

use of org.apache.ratis.statemachine.SnapshotInfo in project incubator-ratis by apache.

the class LeaderElection method askForVotes.

/**
 * After a peer changes its role to candidate, it invokes this method to
 * send out requestVote rpc to all other peers.
 */
private void askForVotes() throws InterruptedException, IOException {
    final ServerState state = server.getState();
    while (running && server.isCandidate()) {
        // one round of requestVotes
        final long electionTerm;
        synchronized (server) {
            electionTerm = state.initElection();
            server.getState().persistMetadata();
        }
        LOG.info(state.getSelfId() + ": begin an election in Term " + electionTerm);
        TermIndex lastEntry = state.getLog().getLastEntryTermIndex();
        if (lastEntry == null) {
            // lastEntry may need to be derived from snapshot
            SnapshotInfo snapshot = state.getLatestSnapshot();
            if (snapshot != null) {
                lastEntry = snapshot.getTermIndex();
            }
        }
        final ResultAndTerm r;
        if (others.isEmpty()) {
            r = new ResultAndTerm(Result.PASSED, electionTerm);
        } else {
            try {
                initExecutor();
                int submitted = submitRequests(electionTerm, lastEntry);
                r = waitForResults(electionTerm, submitted);
            } finally {
                if (executor != null) {
                    executor.shutdown();
                }
            }
        }
        synchronized (server) {
            if (electionTerm != state.getCurrentTerm() || !running || !server.isCandidate()) {
                // term already passed or no longer a candidate.
                return;
            }
            switch(r.result) {
                case PASSED:
                    server.changeToLeader();
                    return;
                case SHUTDOWN:
                    LOG.info("{} received shutdown response when requesting votes.", server.getId());
                    server.getProxy().close();
                    return;
                case REJECTED:
                case DISCOVERED_A_NEW_TERM:
                    final long term = r.term > server.getState().getCurrentTerm() ? r.term : server.getState().getCurrentTerm();
                    server.changeToFollower(term, true);
                    return;
                case TIMEOUT:
            }
        }
    }
}

Example 2 with SnapshotInfo

use of org.apache.ratis.statemachine.SnapshotInfo in project incubator-ratis by apache.

the class ServerState method isLogUpToDate.

boolean isLogUpToDate(TermIndex candidateLastEntry) {
    TermIndex local = log.getLastEntryTermIndex();
    // need to take into account snapshot
    SnapshotInfo snapshot = server.getStateMachine().getLatestSnapshot();
    if (local == null && snapshot == null) {
        return true;
    } else if (candidateLastEntry == null) {
        return false;
    }
    if (local == null || (snapshot != null && snapshot.getIndex() > local.getIndex())) {
        local = snapshot.getTermIndex();
    }
    return local.compareTo(candidateLastEntry) <= 0;
}

Example 3 with SnapshotInfo

use of org.apache.ratis.statemachine.SnapshotInfo in project incubator-ratis by apache.

the class ServerState method initStatemachine.

private long initStatemachine(StateMachine sm, RaftProperties properties) throws IOException {
    sm.initialize(selfId, properties, storage);
    storage.setStateMachineStorage(sm.getStateMachineStorage());
    SnapshotInfo snapshot = sm.getLatestSnapshot();
    if (snapshot == null || snapshot.getTermIndex().getIndex() < 0) {
        return RaftServerConstants.INVALID_LOG_INDEX;
    }
    // get the raft configuration from the snapshot
    RaftConfiguration raftConf = sm.getRaftConfiguration();
    if (raftConf != null) {
        configurationManager.addConfiguration(raftConf.getLogEntryIndex(), raftConf);
    }
    return snapshot.getIndex();
}

Example 4 with SnapshotInfo

use of org.apache.ratis.statemachine.SnapshotInfo in project incubator-ratis by apache.

the class StateMachineUpdater method run.

@Override
public void run() {
    final RaftStorage storage = server.getState().getStorage();
    while (isRunning()) {
        try {
            synchronized (this) {
                // Thus initially lastAppliedIndex can be greater than lastCommitted.
                while (lastAppliedIndex >= raftLog.getLastCommittedIndex()) {
                    wait();
                }
            }
            final long committedIndex = raftLog.getLastCommittedIndex();
            Preconditions.assertTrue(lastAppliedIndex < committedIndex);
            if (state == State.RELOAD) {
                Preconditions.assertTrue(stateMachine.getLifeCycleState() == LifeCycle.State.PAUSED);
                stateMachine.reinitialize(server.getId(), properties, storage);
                SnapshotInfo snapshot = stateMachine.getLatestSnapshot();
                Preconditions.assertTrue(snapshot != null && snapshot.getIndex() > lastAppliedIndex, "Snapshot: %s, lastAppliedIndex: %s", snapshot, lastAppliedIndex);
                lastAppliedIndex = snapshot.getIndex();
                lastSnapshotIndex = snapshot.getIndex();
                state = State.RUNNING;
            }
            final MemoizedSupplier<List<CompletableFuture<Message>>> futures = MemoizedSupplier.valueOf(() -> new ArrayList<>());
            while (lastAppliedIndex < committedIndex) {
                final long nextIndex = lastAppliedIndex + 1;
                final LogEntryProto next = raftLog.get(nextIndex);
                if (next != null) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("{}: applying nextIndex={}, nextLog={}", this, nextIndex, ServerProtoUtils.toString(next));
                    }
                    final CompletableFuture<Message> f = server.applyLogToStateMachine(next);
                    if (f != null) {
                        futures.get().add(f);
                    }
                    lastAppliedIndex = nextIndex;
                } else {
                    LOG.debug("{}: logEntry {} is null. There may be snapshot to load. state:{}", this, nextIndex, state);
                    break;
                }
            }
            // check if need to trigger a snapshot
            if (shouldTakeSnapshot(lastAppliedIndex)) {
                if (futures.isInitialized()) {
                    JavaUtils.allOf(futures.get()).get();
                }
                stateMachine.takeSnapshot();
                // TODO purge logs, including log cache. but should keep log for leader's RPCSenders
                lastSnapshotIndex = lastAppliedIndex;
            }
        } catch (InterruptedException e) {
            if (!isRunning()) {
                LOG.info("{}: the StateMachineUpdater is interrupted and will exit.", this);
            } else {
                final String s = this + ": the StateMachineUpdater is wrongly interrupted";
                ExitUtils.terminate(1, s, e, LOG);
            }
        } catch (Throwable t) {
            final String s = this + ": the StateMachineUpdater hits Throwable";
            ExitUtils.terminate(2, s, t, LOG);
        }
    }
}

Example 5 with SnapshotInfo

use of org.apache.ratis.statemachine.SnapshotInfo in project incubator-ratis by apache.

the class GRpcLogAppender method run.

@Override
public void run() {
    while (isAppenderRunning()) {
        if (shouldSendRequest()) {
            SnapshotInfo snapshot = shouldInstallSnapshot();
            if (snapshot != null) {
                installSnapshot(snapshot, snapshotResponseHandler);
            } else {
                // keep appending log entries or sending heartbeats
                try {
                    appendLog();
                } catch (RaftLogIOException e) {
                    LOG.error(this + " hit IOException while loading raft log", e);
                    stopSender();
                }
            }
        }
        if (isAppenderRunning() && !shouldSendRequest()) {
            // use lastSend time instead of lastResponse time
            final long waitTime = getHeartbeatRemainingTime(follower.getLastRpcTime());
            if (waitTime > 0) {
                synchronized (this) {
                    try {
                        LOG.debug("{} decides to wait {}ms before appending to {}", server.getId(), waitTime, follower.getPeer());
                        wait(waitTime);
                    } catch (InterruptedException ignored) {
                    }
                }
            }
        }
    }
    appendLogRequestObserver.onCompleted();
}