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/*
* Copyright (c) 2016 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.controller.cluster.datastore;
import static java.util.Objects.requireNonNull;
import com.google.common.base.MoreObjects;
import com.google.common.base.MoreObjects.ToStringHelper;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.eclipse.jdt.annotation.NonNull;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.controller.cluster.access.commands.CreateLocalHistoryRequest;
import org.opendaylight.controller.cluster.access.commands.DeadHistoryException;
import org.opendaylight.controller.cluster.access.commands.DestroyLocalHistoryRequest;
import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
import org.opendaylight.controller.cluster.access.commands.LocalHistorySuccess;
import org.opendaylight.controller.cluster.access.commands.OutOfSequenceEnvelopeException;
import org.opendaylight.controller.cluster.access.commands.PurgeLocalHistoryRequest;
import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
import org.opendaylight.controller.cluster.access.commands.UnknownHistoryException;
import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
import org.opendaylight.controller.cluster.access.concepts.RequestException;
import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
import org.opendaylight.controller.cluster.datastore.ShardDataTreeCohort.State;
import org.opendaylight.controller.cluster.datastore.utils.MutableUnsignedLongSet;
import org.opendaylight.yangtools.concepts.Identifiable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Frontend state as observed by the shard leader. This class is responsible for tracking generations and sequencing
* in the frontend/backend conversation. This class is NOT thread-safe.
*
* @author Robert Varga
*/
abstract class LeaderFrontendState implements Identifiable {
static final class Disabled extends LeaderFrontendState {
Disabled(final String persistenceId, final ClientIdentifier clientId, final ShardDataTree tree) {
super(persistenceId, clientId, tree);
}
@Override
LocalHistorySuccess handleLocalHistoryRequest(final LocalHistoryRequest request,
final RequestEnvelope envelope, final long now) throws RequestException {
throw new UnsupportedRequestException(request);
}
@Override
TransactionSuccess handleTransactionRequest(final TransactionRequest request,
final RequestEnvelope envelope, final long now) throws RequestException {
throw new UnsupportedRequestException(request);
}
}
static final class Enabled extends LeaderFrontendState {
// Histories which have not been purged
private final Map localHistories;
// UnsignedLongSet performs automatic merging, hence we keep minimal state tracking information
private final MutableUnsignedLongSet purgedHistories;
// Used for all standalone transactions
private final AbstractFrontendHistory standaloneHistory;
private long expectedTxSequence;
private Long lastSeenHistory = null;
Enabled(final String persistenceId, final ClientIdentifier clientId, final ShardDataTree tree) {
this(persistenceId, clientId, tree, MutableUnsignedLongSet.of(),
StandaloneFrontendHistory.create(persistenceId, clientId, tree), new HashMap<>());
}
Enabled(final String persistenceId, final ClientIdentifier clientId, final ShardDataTree tree,
final MutableUnsignedLongSet purgedHistories, final AbstractFrontendHistory standaloneHistory,
final Map localHistories) {
super(persistenceId, clientId, tree);
this.purgedHistories = requireNonNull(purgedHistories);
this.standaloneHistory = requireNonNull(standaloneHistory);
this.localHistories = requireNonNull(localHistories);
}
@Override
@Nullable LocalHistorySuccess handleLocalHistoryRequest(final LocalHistoryRequest request,
final RequestEnvelope envelope, final long now) throws RequestException {
checkRequestSequence(envelope);
try {
if (request instanceof CreateLocalHistoryRequest) {
return handleCreateHistory((CreateLocalHistoryRequest) request, envelope, now);
} else if (request instanceof DestroyLocalHistoryRequest) {
return handleDestroyHistory((DestroyLocalHistoryRequest) request, envelope, now);
} else if (request instanceof PurgeLocalHistoryRequest) {
return handlePurgeHistory((PurgeLocalHistoryRequest) request, envelope, now);
} else {
LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
throw new UnsupportedRequestException(request);
}
} finally {
expectNextRequest();
}
}
@Override
@Nullable TransactionSuccess handleTransactionRequest(final TransactionRequest request,
final RequestEnvelope envelope, final long now) throws RequestException {
checkRequestSequence(envelope);
try {
final LocalHistoryIdentifier lhId = request.getTarget().getHistoryId();
final AbstractFrontendHistory history;
if (lhId.getHistoryId() != 0) {
history = localHistories.get(lhId);
if (history == null) {
if (purgedHistories.contains(lhId.getHistoryId())) {
LOG.warn("{}: rejecting request {} to purged history", persistenceId(), request);
throw new DeadHistoryException(purgedHistories.toRangeSet());
}
LOG.warn("{}: rejecting unknown history request {}", persistenceId(), request);
throw new UnknownHistoryException(lastSeenHistory);
}
} else {
history = standaloneHistory;
}
return history.handleTransactionRequest(request, envelope, now);
} finally {
expectNextRequest();
}
}
@Override
void reconnect() {
expectedTxSequence = 0;
super.reconnect();
}
@Override
void retire() {
super.retire();
// Clear out all transaction chains
localHistories.values().forEach(AbstractFrontendHistory::retire);
localHistories.clear();
standaloneHistory.retire();
}
@Override
ToStringHelper addToStringAttributes(final ToStringHelper helper) {
return super.addToStringAttributes(helper).add("purgedHistories", purgedHistories);
}
private LocalHistorySuccess handleCreateHistory(final CreateLocalHistoryRequest request,
final RequestEnvelope envelope, final long now) throws RequestException {
final LocalHistoryIdentifier historyId = request.getTarget();
final AbstractFrontendHistory existing = localHistories.get(historyId);
if (existing != null) {
// History already exists: report success
LOG.debug("{}: history {} already exists", persistenceId(), historyId);
return new LocalHistorySuccess(historyId, request.getSequence());
}
// We have not found the history. Before we create it we need to check history ID sequencing so that we do
// not end up resurrecting a purged history.
if (purgedHistories.contains(historyId.getHistoryId())) {
LOG.debug("{}: rejecting purged request {}", persistenceId(), request);
throw new DeadHistoryException(purgedHistories.toRangeSet());
}
// Update last history we have seen
if (lastSeenHistory == null || Long.compareUnsigned(lastSeenHistory, historyId.getHistoryId()) < 0) {
lastSeenHistory = historyId.getHistoryId();
}
// We have to send the response only after persistence has completed
final ShardDataTreeTransactionChain chain = tree().ensureTransactionChain(historyId, () -> {
LOG.debug("{}: persisted history {}", persistenceId(), historyId);
envelope.sendSuccess(new LocalHistorySuccess(historyId, request.getSequence()),
tree().readTime() - now);
});
localHistories.put(historyId, LocalFrontendHistory.create(persistenceId(), tree(), chain));
LOG.debug("{}: created history {}", persistenceId(), historyId);
return null;
}
private LocalHistorySuccess handleDestroyHistory(final DestroyLocalHistoryRequest request,
final RequestEnvelope envelope, final long now) {
final LocalHistoryIdentifier id = request.getTarget();
final LocalFrontendHistory existing = localHistories.get(id);
if (existing == null) {
// History does not exist: report success
LOG.debug("{}: history {} does not exist, nothing to destroy", persistenceId(), id);
return new LocalHistorySuccess(id, request.getSequence());
}
existing.destroy(request.getSequence(), envelope, now);
return null;
}
private LocalHistorySuccess handlePurgeHistory(final PurgeLocalHistoryRequest request,
final RequestEnvelope envelope, final long now) {
final LocalHistoryIdentifier id = request.getTarget();
final LocalFrontendHistory existing = localHistories.remove(id);
if (existing == null) {
LOG.debug("{}: history {} has already been purged", persistenceId(), id);
return new LocalHistorySuccess(id, request.getSequence());
}
LOG.debug("{}: purging history {}", persistenceId(), id);
purgedHistories.add(id.getHistoryId());
existing.purge(request.getSequence(), envelope, now);
return null;
}
private void checkRequestSequence(final RequestEnvelope envelope) throws OutOfSequenceEnvelopeException {
if (expectedTxSequence != envelope.getTxSequence()) {
throw new OutOfSequenceEnvelopeException(expectedTxSequence);
}
}
private void expectNextRequest() {
expectedTxSequence++;
}
}
private static final Logger LOG = LoggerFactory.getLogger(LeaderFrontendState.class);
private final @NonNull ClientIdentifier clientId;
private final @NonNull String persistenceId;
private final @NonNull ShardDataTree tree;
private long lastConnectTicks;
private long lastSeenTicks;
// TODO: explicit failover notification
// Record the ActorRef for the originating actor and when we switch to being a leader send a notification
// to the frontend client -- that way it can immediately start sending requests
// TODO: add statistics:
// - number of requests processed
// - number of histories processed
// - per-RequestException throw counters
LeaderFrontendState(final String persistenceId, final ClientIdentifier clientId, final ShardDataTree tree) {
this.persistenceId = requireNonNull(persistenceId);
this.clientId = requireNonNull(clientId);
this.tree = requireNonNull(tree);
lastSeenTicks = tree.readTime();
}
@Override
public final ClientIdentifier getIdentifier() {
return clientId;
}
final String persistenceId() {
return persistenceId;
}
final long getLastConnectTicks() {
return lastConnectTicks;
}
final long getLastSeenTicks() {
return lastSeenTicks;
}
final ShardDataTree tree() {
return tree;
}
final void touch() {
lastSeenTicks = tree.readTime();
}
abstract @Nullable LocalHistorySuccess handleLocalHistoryRequest(LocalHistoryRequest request,
RequestEnvelope envelope, long now) throws RequestException;
abstract @Nullable TransactionSuccess handleTransactionRequest(TransactionRequest request,
RequestEnvelope envelope, long now) throws RequestException;
void reconnect() {
lastConnectTicks = tree.readTime();
}
void retire() {
// Hunt down any transactions associated with this frontend
final Iterator it = tree.cohortIterator();
while (it.hasNext()) {
final SimpleShardDataTreeCohort cohort = it.next();
if (clientId.equals(cohort.getIdentifier().getHistoryId().getClientId())) {
if (cohort.getState() != State.COMMIT_PENDING) {
LOG.debug("{}: Retiring transaction {}", persistenceId, cohort.getIdentifier());
it.remove();
} else {
LOG.debug("{}: Transaction {} already committing, not retiring it", persistenceId,
cohort.getIdentifier());
}
}
}
}
@Override
public final String toString() {
return addToStringAttributes(MoreObjects.toStringHelper(this)).toString();
}
ToStringHelper addToStringAttributes(final ToStringHelper helper) {
return helper.add("clientId", clientId).add("nanosAgo", tree.readTime() - lastSeenTicks);
}
}
