2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.controller.cluster.datastore;
10 import static com.google.common.base.Preconditions.checkState;
11 import static com.google.common.base.Verify.verify;
12 import static com.google.common.base.Verify.verifyNotNull;
13 import static java.util.Objects.requireNonNull;
15 import akka.actor.ActorRef;
16 import akka.actor.ActorSelection;
17 import akka.actor.Cancellable;
18 import akka.actor.ExtendedActorSystem;
19 import akka.actor.PoisonPill;
20 import akka.actor.Props;
21 import akka.actor.Status;
22 import akka.actor.Status.Failure;
23 import akka.persistence.RecoveryCompleted;
24 import akka.persistence.SnapshotOffer;
25 import akka.serialization.JavaSerializer;
26 import akka.serialization.Serialization;
27 import com.google.common.annotations.VisibleForTesting;
28 import com.google.common.base.Ticker;
29 import com.google.common.collect.ImmutableList;
30 import com.google.common.collect.ImmutableMap;
31 import com.google.common.collect.ImmutableSet;
32 import com.google.common.collect.Range;
33 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
34 import java.io.IOException;
35 import java.util.Arrays;
36 import java.util.Collection;
37 import java.util.Collections;
38 import java.util.HashMap;
40 import java.util.Optional;
41 import java.util.OptionalLong;
42 import java.util.concurrent.TimeUnit;
43 import org.eclipse.jdt.annotation.NonNull;
44 import org.eclipse.jdt.annotation.Nullable;
45 import org.opendaylight.controller.cluster.access.ABIVersion;
46 import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
47 import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
48 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
49 import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
50 import org.opendaylight.controller.cluster.access.commands.OutOfSequenceEnvelopeException;
51 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
52 import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
53 import org.opendaylight.controller.cluster.access.concepts.FrontendIdentifier;
54 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
55 import org.opendaylight.controller.cluster.access.concepts.Request;
56 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
57 import org.opendaylight.controller.cluster.access.concepts.RequestException;
58 import org.opendaylight.controller.cluster.access.concepts.RequestSuccess;
59 import org.opendaylight.controller.cluster.access.concepts.RetiredGenerationException;
60 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
61 import org.opendaylight.controller.cluster.access.concepts.SliceableMessage;
62 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
63 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
64 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
65 import org.opendaylight.controller.cluster.common.actor.Dispatchers;
66 import org.opendaylight.controller.cluster.common.actor.Dispatchers.DispatcherType;
67 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
68 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
69 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
70 import org.opendaylight.controller.cluster.datastore.actors.JsonExportActor;
71 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
72 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
73 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
74 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
75 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
76 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
77 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
78 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
79 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
80 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
81 import org.opendaylight.controller.cluster.datastore.messages.DataTreeChangedReply;
82 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
83 import org.opendaylight.controller.cluster.datastore.messages.GetKnownClients;
84 import org.opendaylight.controller.cluster.datastore.messages.GetKnownClientsReply;
85 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
86 import org.opendaylight.controller.cluster.datastore.messages.MakeLeaderLocal;
87 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
88 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
89 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
90 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
91 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
92 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
93 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot;
94 import org.opendaylight.controller.cluster.datastore.persisted.DatastoreSnapshot.ShardSnapshot;
95 import org.opendaylight.controller.cluster.datastore.persisted.DisableTrackingPayload;
96 import org.opendaylight.controller.cluster.messaging.MessageAssembler;
97 import org.opendaylight.controller.cluster.messaging.MessageSlicer;
98 import org.opendaylight.controller.cluster.messaging.SliceOptions;
99 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
100 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
101 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
102 import org.opendaylight.controller.cluster.raft.LeadershipTransferFailedException;
103 import org.opendaylight.controller.cluster.raft.RaftActor;
104 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
105 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
106 import org.opendaylight.controller.cluster.raft.RaftState;
107 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
108 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
109 import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
110 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
111 import org.opendaylight.controller.cluster.raft.messages.Payload;
112 import org.opendaylight.controller.cluster.raft.messages.RequestLeadership;
113 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
114 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.config.distributed.datastore.provider.rev140612.DataStoreProperties.ExportOnRecovery;
115 import org.opendaylight.yangtools.concepts.Identifier;
116 import org.opendaylight.yangtools.yang.data.tree.api.DataTree;
117 import org.opendaylight.yangtools.yang.data.tree.api.DataValidationFailedException;
118 import org.opendaylight.yangtools.yang.data.tree.api.TreeType;
119 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
120 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContextProvider;
121 import scala.concurrent.duration.FiniteDuration;
124 * A Shard represents a portion of the logical data tree.
127 * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
129 // FIXME: non-final for testing?
130 public class Shard extends RaftActor {
133 static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
135 public String toString() {
136 return "txCommitTimeoutCheck";
141 static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
143 public String toString() {
144 return "getShardMBeanMessage";
148 static final Object RESUME_NEXT_PENDING_TRANSACTION = new Object() {
150 public String toString() {
151 return "resumeNextPendingTransaction";
155 // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
156 public static final String DEFAULT_NAME = "default";
158 private static final Collection<ABIVersion> SUPPORTED_ABIVERSIONS;
160 // Make sure to keep this in sync with the journal configuration in factory-akka.conf
161 public static final String NON_PERSISTENT_JOURNAL_ID = "akka.persistence.non-persistent.journal";
164 final ABIVersion[] values = ABIVersion.values();
165 final ABIVersion[] real = Arrays.copyOfRange(values, 1, values.length - 1);
166 SUPPORTED_ABIVERSIONS = ImmutableList.copyOf(real).reverse();
169 // FIXME: make this a dynamic property based on mailbox size and maximum number of clients
170 private static final int CLIENT_MAX_MESSAGES = 1000;
172 // The state of this Shard
173 private final ShardDataTree store;
175 /// The name of this shard
176 private final String name;
178 private final String shardName;
180 private final ShardStats shardMBean;
182 private final ShardDataTreeListenerInfoMXBeanImpl listenerInfoMXBean;
184 private DatastoreContext datastoreContext;
186 private final ShardCommitCoordinator commitCoordinator;
188 private long transactionCommitTimeout;
190 private Cancellable txCommitTimeoutCheckSchedule;
192 private final Optional<ActorRef> roleChangeNotifier;
194 private final MessageTracker appendEntriesReplyTracker;
196 private final ShardTransactionActorFactory transactionActorFactory;
198 private final ShardSnapshotCohort snapshotCohort;
200 private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
202 private ShardSnapshot restoreFromSnapshot;
204 private final ShardTransactionMessageRetrySupport messageRetrySupport;
207 final FrontendMetadata frontendMetadata;
209 private Map<FrontendIdentifier, LeaderFrontendState> knownFrontends = ImmutableMap.of();
210 private boolean paused;
212 private final MessageSlicer responseMessageSlicer;
213 private final Dispatchers dispatchers;
215 private final MessageAssembler requestMessageAssembler;
217 private final ExportOnRecovery exportOnRecovery;
219 private final ActorRef exportActor;
221 @SuppressFBWarnings(value = "MC_OVERRIDABLE_METHOD_CALL_IN_CONSTRUCTOR", justification = "Akka class design")
222 Shard(final AbstractBuilder<?, ?> builder) {
223 super(builder.getId().toString(), builder.getPeerAddresses(),
224 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
226 name = builder.getId().toString();
227 shardName = builder.getId().getShardName();
228 datastoreContext = builder.getDatastoreContext();
229 restoreFromSnapshot = builder.getRestoreFromSnapshot();
230 frontendMetadata = new FrontendMetadata(name);
231 exportOnRecovery = datastoreContext.getExportOnRecovery();
233 exportActor = switch (exportOnRecovery) {
234 case Json -> getContext().actorOf(JsonExportActor.props(builder.getSchemaContext(),
235 datastoreContext.getRecoveryExportBaseDir()));
239 setPersistence(datastoreContext.isPersistent());
241 LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
243 ShardDataTreeChangeListenerPublisherActorProxy treeChangeListenerPublisher =
244 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher", name);
245 if (builder.getDataTree() != null) {
246 store = new ShardDataTree(this, builder.getSchemaContext(), builder.getDataTree(),
247 treeChangeListenerPublisher, name,
250 store = new ShardDataTree(this, builder.getSchemaContext(), builder.getTreeType(),
251 builder.getDatastoreContext().getStoreRoot(), treeChangeListenerPublisher, name,
255 shardMBean = ShardStats.create(name, datastoreContext.getDataStoreMXBeanType(), this);
257 if (isMetricsCaptureEnabled()) {
258 getContext().become(new MeteringBehavior(this));
261 commitCoordinator = new ShardCommitCoordinator(store, LOG, name);
263 setTransactionCommitTimeout();
265 // create a notifier actor for each cluster member
266 roleChangeNotifier = createRoleChangeNotifier(name);
268 appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
269 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
271 dispatchers = new Dispatchers(context().system().dispatchers());
272 transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
273 dispatchers.getDispatcherPath(Dispatchers.DispatcherType.Transaction),
274 self(), getContext(), shardMBean, builder.getId().getShardName());
276 snapshotCohort = ShardSnapshotCohort.create(getContext(), builder.getId().getMemberName(), store, LOG,
277 name, datastoreContext);
279 messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
281 responseMessageSlicer = MessageSlicer.builder().logContext(name)
282 .messageSliceSize(datastoreContext.getMaximumMessageSliceSize())
283 .fileBackedStreamFactory(getRaftActorContext().getFileBackedOutputStreamFactory())
284 .expireStateAfterInactivity(2, TimeUnit.MINUTES).build();
286 requestMessageAssembler = MessageAssembler.builder().logContext(name)
287 .fileBackedStreamFactory(getRaftActorContext().getFileBackedOutputStreamFactory())
288 .assembledMessageCallback((message, sender) -> self().tell(message, sender))
289 .expireStateAfterInactivity(datastoreContext.getRequestTimeout(), TimeUnit.NANOSECONDS).build();
291 listenerInfoMXBean = new ShardDataTreeListenerInfoMXBeanImpl(name, datastoreContext.getDataStoreMXBeanType(),
293 listenerInfoMXBean.register();
296 private void setTransactionCommitTimeout() {
297 transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
298 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
301 private Optional<ActorRef> createRoleChangeNotifier(final String shardId) {
302 ActorRef shardRoleChangeNotifier = getContext().actorOf(
303 RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
304 return Optional.of(shardRoleChangeNotifier);
308 public final void postStop() throws Exception {
309 LOG.info("Stopping Shard {}", persistenceId());
313 messageRetrySupport.close();
315 if (txCommitTimeoutCheckSchedule != null) {
316 txCommitTimeoutCheckSchedule.cancel();
319 commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
321 shardMBean.unregisterMBean();
322 listenerInfoMXBean.unregister();
326 protected final void handleRecover(final Object message) {
327 LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
330 super.handleRecover(message);
332 switch (exportOnRecovery) {
334 if (message instanceof SnapshotOffer) {
335 exportActor.tell(new JsonExportActor.ExportSnapshot(store.readCurrentData().get(), name),
336 ActorRef.noSender());
337 } else if (message instanceof ReplicatedLogEntry) {
338 exportActor.tell(new JsonExportActor.ExportJournal((ReplicatedLogEntry) message),
339 ActorRef.noSender());
340 } else if (message instanceof RecoveryCompleted) {
341 exportActor.tell(new JsonExportActor.FinishExport(name), ActorRef.noSender());
342 exportActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
350 if (LOG.isTraceEnabled()) {
351 appendEntriesReplyTracker.begin();
356 // non-final for TestShard
357 protected void handleNonRaftCommand(final Object message) {
358 try (MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
359 final Optional<Error> maybeError = context.error();
360 if (maybeError.isPresent()) {
361 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
365 store.resetTransactionBatch();
367 if (message instanceof RequestEnvelope) {
368 handleRequestEnvelope((RequestEnvelope)message);
369 } else if (MessageAssembler.isHandledMessage(message)) {
370 handleRequestAssemblerMessage(message);
371 } else if (message instanceof ConnectClientRequest) {
372 handleConnectClient((ConnectClientRequest)message);
373 } else if (CreateTransaction.isSerializedType(message)) {
374 handleCreateTransaction(message);
375 } else if (message instanceof BatchedModifications) {
376 handleBatchedModifications((BatchedModifications)message);
377 } else if (message instanceof ForwardedReadyTransaction) {
378 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
379 } else if (message instanceof ReadyLocalTransaction) {
380 handleReadyLocalTransaction((ReadyLocalTransaction)message);
381 } else if (CanCommitTransaction.isSerializedType(message)) {
382 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
383 } else if (CommitTransaction.isSerializedType(message)) {
384 handleCommitTransaction(CommitTransaction.fromSerializable(message));
385 } else if (AbortTransaction.isSerializedType(message)) {
386 handleAbortTransaction(AbortTransaction.fromSerializable(message));
387 } else if (CloseTransactionChain.isSerializedType(message)) {
388 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
389 } else if (message instanceof DataTreeChangedReply) {
391 } else if (message instanceof RegisterDataTreeChangeListener) {
392 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
393 } else if (message instanceof UpdateSchemaContext) {
394 updateSchemaContext((UpdateSchemaContext) message);
395 } else if (message instanceof PeerAddressResolved resolved) {
396 setPeerAddress(resolved.getPeerId(), resolved.getPeerAddress());
397 } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
398 commitTimeoutCheck();
399 } else if (message instanceof DatastoreContext) {
400 onDatastoreContext((DatastoreContext)message);
401 } else if (message instanceof RegisterRoleChangeListener) {
402 roleChangeNotifier.get().forward(message, context());
403 } else if (message instanceof FollowerInitialSyncUpStatus) {
404 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
405 context().parent().tell(message, self());
406 } else if (GET_SHARD_MBEAN_MESSAGE.equals(message)) {
407 sender().tell(getShardMBean(), self());
408 } else if (message instanceof GetShardDataTree) {
409 sender().tell(store.getDataTree(), self());
410 } else if (message instanceof ServerRemoved) {
411 context().parent().forward(message, context());
412 } else if (ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
413 messageRetrySupport.onTimerMessage(message);
414 } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
415 store.processCohortRegistryCommand(getSender(),
416 (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
417 } else if (message instanceof MakeLeaderLocal) {
419 } else if (RESUME_NEXT_PENDING_TRANSACTION.equals(message)) {
420 store.resumeNextPendingTransaction();
421 } else if (GetKnownClients.INSTANCE.equals(message)) {
422 handleGetKnownClients();
423 } else if (!responseMessageSlicer.handleMessage(message)) {
424 super.handleNonRaftCommand(message);
429 private void handleRequestAssemblerMessage(final Object message) {
430 dispatchers.getDispatcher(DispatcherType.Serialization).execute(() -> {
431 JavaSerializer.currentSystem().value_$eq((ExtendedActorSystem) context().system());
432 requestMessageAssembler.handleMessage(message, self());
436 @SuppressWarnings("checkstyle:IllegalCatch")
437 private void handleRequestEnvelope(final RequestEnvelope envelope) {
438 final long now = ticker().read();
440 final RequestSuccess<?, ?> success = handleRequest(envelope, now);
441 if (success != null) {
442 final long executionTimeNanos = ticker().read() - now;
443 if (success instanceof SliceableMessage) {
444 dispatchers.getDispatcher(DispatcherType.Serialization).execute(() ->
445 responseMessageSlicer.slice(SliceOptions.builder().identifier(success.getTarget())
446 .message(envelope.newSuccessEnvelope(success, executionTimeNanos))
447 .sendTo(envelope.getMessage().getReplyTo()).replyTo(self())
448 .onFailureCallback(t -> LOG.warn("Error slicing response {}", success, t)).build()));
450 envelope.sendSuccess(success, executionTimeNanos);
453 } catch (RequestException e) {
454 LOG.debug("{}: request {} failed", persistenceId(), envelope, e);
455 envelope.sendFailure(e, ticker().read() - now);
456 } catch (Exception e) {
457 LOG.debug("{}: request {} caused failure", persistenceId(), envelope, e);
458 envelope.sendFailure(new RuntimeRequestException("Request failed to process", e),
459 ticker().read() - now);
463 private void commitTimeoutCheck() {
464 store.checkForExpiredTransactions(transactionCommitTimeout, this::updateAccess);
465 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
466 requestMessageAssembler.checkExpiredAssembledMessageState();
469 private OptionalLong updateAccess(final SimpleShardDataTreeCohort cohort) {
470 final FrontendIdentifier frontend = cohort.getIdentifier().getHistoryId().getClientId().getFrontendId();
471 final LeaderFrontendState state = knownFrontends.get(frontend);
473 // Not tell-based protocol, do nothing
474 return OptionalLong.empty();
477 if (isIsolatedLeader()) {
478 // We are isolated and no new request can come through until we emerge from it. We are still updating
479 // liveness of frontend when we see it attempting to communicate. Use the last access timer.
480 return OptionalLong.of(state.getLastSeenTicks());
483 // If this frontend has freshly connected, give it some time to catch up before killing its transactions.
484 return OptionalLong.of(state.getLastConnectTicks());
487 private void disableTracking(final DisableTrackingPayload payload) {
488 final ClientIdentifier clientId = payload.getIdentifier();
489 LOG.debug("{}: disabling tracking of {}", persistenceId(), clientId);
490 frontendMetadata.disableTracking(clientId);
493 final FrontendIdentifier frontendId = clientId.getFrontendId();
494 final LeaderFrontendState frontend = knownFrontends.get(frontendId);
495 if (frontend != null) {
496 if (clientId.equals(frontend.getIdentifier())) {
497 if (!(frontend instanceof LeaderFrontendState.Disabled)) {
498 verify(knownFrontends.replace(frontendId, frontend,
499 new LeaderFrontendState.Disabled(persistenceId(), clientId, store)));
500 LOG.debug("{}: leader state for {} disabled", persistenceId(), clientId);
502 LOG.debug("{}: leader state {} is already disabled", persistenceId(), frontend);
505 LOG.debug("{}: leader state {} does not match {}", persistenceId(), frontend, clientId);
508 LOG.debug("{}: leader state for {} not found", persistenceId(), clientId);
509 knownFrontends.put(frontendId, new LeaderFrontendState.Disabled(persistenceId(), clientId,
515 private void onMakeLeaderLocal() {
516 LOG.debug("{}: onMakeLeaderLocal received", persistenceId());
518 getSender().tell(new Status.Success(null), getSelf());
522 final ActorSelection leader = getLeader();
524 if (leader == null) {
525 // Leader is not present. The cluster is most likely trying to
526 // elect a leader and we should let that run its normal course
528 // TODO we can wait for the election to complete and retry the
529 // request. We can also let the caller retry by sending a flag
530 // in the response indicating the request is "reTryable".
531 getSender().tell(new Failure(
532 new LeadershipTransferFailedException("We cannot initiate leadership transfer to local node. "
533 + "Currently there is no leader for " + persistenceId())),
538 leader.tell(new RequestLeadership(getId(), getSender()), getSelf());
541 // Acquire our frontend tracking handle and verify generation matches
542 private @Nullable LeaderFrontendState findFrontend(final ClientIdentifier clientId) throws RequestException {
543 final LeaderFrontendState existing = knownFrontends.get(clientId.getFrontendId());
544 if (existing != null) {
545 final int cmp = Long.compareUnsigned(existing.getIdentifier().getGeneration(), clientId.getGeneration());
551 LOG.debug("{}: rejecting request from outdated client {}", persistenceId(), clientId);
552 throw new RetiredGenerationException(clientId.getGeneration(),
553 existing.getIdentifier().getGeneration());
556 LOG.info("{}: retiring state {}, outdated by request from client {}", persistenceId(), existing, clientId);
558 knownFrontends.remove(clientId.getFrontendId());
560 LOG.debug("{}: client {} is not yet known", persistenceId(), clientId);
566 private LeaderFrontendState getFrontend(final ClientIdentifier clientId) throws RequestException {
567 final LeaderFrontendState ret = findFrontend(clientId);
572 // TODO: a dedicated exception would be better, but this is technically true, too
573 throw new OutOfSequenceEnvelopeException(0);
576 private static @NonNull ABIVersion selectVersion(final ConnectClientRequest message) {
577 final Range<ABIVersion> clientRange = Range.closed(message.getMinVersion(), message.getMaxVersion());
578 for (ABIVersion v : SUPPORTED_ABIVERSIONS) {
579 if (clientRange.contains(v)) {
584 throw new IllegalArgumentException(String.format(
585 "No common version between backend versions %s and client versions %s", SUPPORTED_ABIVERSIONS,
589 @SuppressWarnings("checkstyle:IllegalCatch")
590 private void handleConnectClient(final ConnectClientRequest message) {
592 final ClientIdentifier clientId = message.getTarget();
593 final LeaderFrontendState existing = findFrontend(clientId);
594 if (existing != null) {
598 if (!isLeader() || !isLeaderActive()) {
599 LOG.info("{}: not currently leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
600 + "isLeadershipTransferInProgress: {}.",
601 persistenceId(), message, isLeader(), isLeaderActive(), isLeadershipTransferInProgress());
602 throw new NotLeaderException(getSelf());
605 final ABIVersion selectedVersion = selectVersion(message);
606 final LeaderFrontendState frontend;
607 if (existing == null) {
608 frontend = new LeaderFrontendState.Enabled(persistenceId(), clientId, store);
609 knownFrontends.put(clientId.getFrontendId(), frontend);
610 LOG.debug("{}: created state {} for client {}", persistenceId(), frontend, clientId);
615 frontend.reconnect();
616 message.getReplyTo().tell(new ConnectClientSuccess(message.getTarget(), message.getSequence(), getSelf(),
617 ImmutableList.of(), store.getDataTree(), CLIENT_MAX_MESSAGES).toVersion(selectedVersion),
618 ActorRef.noSender());
619 } catch (RequestException | RuntimeException e) {
620 message.getReplyTo().tell(new Failure(e), ActorRef.noSender());
624 private @Nullable RequestSuccess<?, ?> handleRequest(final RequestEnvelope envelope, final long now)
625 throws RequestException {
626 // We are not the leader, hence we want to fail-fast.
627 if (!isLeader() || paused || !isLeaderActive()) {
628 LOG.debug("{}: not currently active leader, rejecting request {}. isLeader: {}, isLeaderActive: {},"
629 + "isLeadershipTransferInProgress: {}, paused: {}",
630 persistenceId(), envelope, isLeader(), isLeaderActive(), isLeadershipTransferInProgress(), paused);
631 throw new NotLeaderException(getSelf());
634 final Request<?, ?> request = envelope.getMessage();
635 if (request instanceof TransactionRequest) {
636 final TransactionRequest<?> txReq = (TransactionRequest<?>)request;
637 final ClientIdentifier clientId = txReq.getTarget().getHistoryId().getClientId();
638 return getFrontend(clientId).handleTransactionRequest(txReq, envelope, now);
639 } else if (request instanceof LocalHistoryRequest) {
640 final LocalHistoryRequest<?> lhReq = (LocalHistoryRequest<?>)request;
641 final ClientIdentifier clientId = lhReq.getTarget().getClientId();
642 return getFrontend(clientId).handleLocalHistoryRequest(lhReq, envelope, now);
644 LOG.warn("{}: rejecting unsupported request {}", persistenceId(), request);
645 throw new UnsupportedRequestException(request);
649 private void handleGetKnownClients() {
650 final ImmutableSet<ClientIdentifier> clients;
652 clients = knownFrontends.values().stream()
653 .map(LeaderFrontendState::getIdentifier)
654 .collect(ImmutableSet.toImmutableSet());
656 clients = frontendMetadata.getClients();
658 sender().tell(new GetKnownClientsReply(clients), self());
661 private boolean hasLeader() {
662 return getLeaderId() != null;
665 final int getPendingTxCommitQueueSize() {
666 return store.getQueueSize();
669 final int getCohortCacheSize() {
670 return commitCoordinator.getCohortCacheSize();
674 protected final Optional<ActorRef> getRoleChangeNotifier() {
675 return roleChangeNotifier;
678 final String getShardName() {
683 protected final LeaderStateChanged newLeaderStateChanged(final String memberId, final String leaderId,
684 final short leaderPayloadVersion) {
685 return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
686 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
689 private void onDatastoreContext(final DatastoreContext context) {
690 datastoreContext = verifyNotNull(context);
692 setTransactionCommitTimeout();
694 setPersistence(datastoreContext.isPersistent());
696 updateConfigParams(datastoreContext.getShardRaftConfig());
699 // applyState() will be invoked once consensus is reached on the payload
700 // non-final for mocking
701 void persistPayload(final Identifier id, final Payload payload, final boolean batchHint) {
702 final boolean canSkipPayload = !hasFollowers() && !persistence().isRecoveryApplicable();
703 if (canSkipPayload) {
704 applyState(self(), id, payload);
706 // We are faking the sender
707 persistData(self(), id, payload, batchHint);
711 private void handleCommitTransaction(final CommitTransaction commit) {
712 final TransactionIdentifier txId = commit.getTransactionId();
714 askProtocolEncountered(txId);
715 commitCoordinator.handleCommit(txId, getSender(), this);
717 ActorSelection leader = getLeader();
718 if (leader == null) {
719 messageRetrySupport.addMessageToRetry(commit, getSender(), "Could not commit transaction " + txId);
721 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
722 leader.forward(commit, getContext());
727 private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
728 final TransactionIdentifier txId = canCommit.getTransactionId();
729 LOG.debug("{}: Can committing transaction {}", persistenceId(), txId);
732 askProtocolEncountered(txId);
733 commitCoordinator.handleCanCommit(txId, getSender(), this);
735 ActorSelection leader = getLeader();
736 if (leader == null) {
737 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
738 "Could not canCommit transaction " + txId);
740 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
741 leader.forward(canCommit, getContext());
746 @SuppressWarnings("checkstyle:IllegalCatch")
747 private void handleBatchedModificationsLocal(final BatchedModifications batched, final ActorRef sender) {
748 askProtocolEncountered(batched.getTransactionId());
751 commitCoordinator.handleBatchedModifications(batched, sender, this);
752 } catch (Exception e) {
753 LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
754 batched.getTransactionId(), e);
755 sender.tell(new Failure(e), getSelf());
759 private void handleBatchedModifications(final BatchedModifications batched) {
760 // This message is sent to prepare the modifications transaction directly on the Shard as an
761 // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
762 // BatchedModifications message, the caller sets the ready flag in the message indicating
763 // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
764 // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
765 // ReadyTransaction message.
767 // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
768 // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
769 // the primary/leader shard. However with timing and caching on the front-end, there's a small
770 // window where it could have a stale leader during leadership transitions.
772 boolean isLeaderActive = isLeaderActive();
773 if (isLeader() && isLeaderActive) {
774 handleBatchedModificationsLocal(batched, getSender());
776 ActorSelection leader = getLeader();
777 if (!isLeaderActive || leader == null) {
778 messageRetrySupport.addMessageToRetry(batched, getSender(),
779 "Could not process BatchedModifications " + batched.getTransactionId());
781 // If this is not the first batch and leadership changed in between batched messages,
782 // we need to reconstruct previous BatchedModifications from the transaction
783 // DataTreeModification, honoring the max batched modification count, and forward all the
784 // previous BatchedModifications to the new leader.
785 Collection<BatchedModifications> newModifications = commitCoordinator
786 .createForwardedBatchedModifications(batched,
787 datastoreContext.getShardBatchedModificationCount());
789 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
790 newModifications.size(), leader);
792 for (BatchedModifications bm : newModifications) {
793 leader.forward(bm, getContext());
799 private boolean failIfIsolatedLeader(final ActorRef sender) {
800 if (isIsolatedLeader()) {
801 sender.tell(new Failure(new NoShardLeaderException(String.format(
802 "Shard %s was the leader but has lost contact with all of its followers. Either all"
803 + " other follower nodes are down or this node is isolated by a network partition.",
804 persistenceId()))), getSelf());
811 protected boolean isIsolatedLeader() {
812 return getRaftState() == RaftState.IsolatedLeader;
815 @SuppressWarnings("checkstyle:IllegalCatch")
816 private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
817 final TransactionIdentifier txId = message.getTransactionId();
818 LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), txId);
820 boolean isLeaderActive = isLeaderActive();
821 if (isLeader() && isLeaderActive) {
822 askProtocolEncountered(txId);
824 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this);
825 } catch (Exception e) {
826 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(), txId, e);
827 getSender().tell(new Failure(e), getSelf());
830 ActorSelection leader = getLeader();
831 if (!isLeaderActive || leader == null) {
832 messageRetrySupport.addMessageToRetry(message, getSender(),
833 "Could not process ready local transaction " + txId);
835 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
836 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
837 leader.forward(message, getContext());
842 private void handleForwardedReadyTransaction(final ForwardedReadyTransaction forwardedReady) {
843 LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionId());
845 boolean isLeaderActive = isLeaderActive();
846 if (isLeader() && isLeaderActive) {
847 askProtocolEncountered(forwardedReady.getTransactionId());
848 commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this);
850 ActorSelection leader = getLeader();
851 if (!isLeaderActive || leader == null) {
852 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
853 "Could not process forwarded ready transaction " + forwardedReady.getTransactionId());
855 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
857 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionId(),
858 forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit(),
859 forwardedReady.getParticipatingShardNames());
860 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
861 leader.forward(readyLocal, getContext());
866 private void handleAbortTransaction(final AbortTransaction abort) {
867 final TransactionIdentifier transactionId = abort.getTransactionId();
868 askProtocolEncountered(transactionId);
869 doAbortTransaction(transactionId, getSender());
872 final void doAbortTransaction(final Identifier transactionID, final ActorRef sender) {
873 commitCoordinator.handleAbort(transactionID, sender, this);
876 private void handleCreateTransaction(final Object message) {
878 createTransaction(CreateTransaction.fromSerializable(message));
879 } else if (getLeader() != null) {
880 getLeader().forward(message, getContext());
882 getSender().tell(new Failure(new NoShardLeaderException(
883 "Could not create a shard transaction", persistenceId())), getSelf());
887 private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
889 final LocalHistoryIdentifier id = closeTransactionChain.getIdentifier();
890 askProtocolEncountered(id.getClientId());
891 store.closeTransactionChain(id);
892 } else if (getLeader() != null) {
893 getLeader().forward(closeTransactionChain, getContext());
895 LOG.warn("{}: Could not close transaction {}", persistenceId(), closeTransactionChain.getIdentifier());
899 @SuppressWarnings("checkstyle:IllegalCatch")
900 private void createTransaction(final CreateTransaction createTransaction) {
901 askProtocolEncountered(createTransaction.getTransactionId());
904 if (TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY
905 && failIfIsolatedLeader(getSender())) {
909 ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
910 createTransaction.getTransactionId());
912 getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
913 createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
914 } catch (Exception e) {
915 getSender().tell(new Failure(e), getSelf());
919 private ActorRef createTransaction(final int transactionType, final TransactionIdentifier transactionId) {
920 LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
921 return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
925 // Called on leader only
926 private void askProtocolEncountered(final TransactionIdentifier transactionId) {
927 askProtocolEncountered(transactionId.getHistoryId().getClientId());
930 // Called on leader only
931 private void askProtocolEncountered(final ClientIdentifier clientId) {
932 final FrontendIdentifier frontend = clientId.getFrontendId();
933 final LeaderFrontendState state = knownFrontends.get(frontend);
934 if (!(state instanceof LeaderFrontendState.Disabled)) {
935 LOG.debug("{}: encountered ask-based client {}, disabling transaction tracking", persistenceId(), clientId);
936 if (knownFrontends.isEmpty()) {
937 knownFrontends = new HashMap<>();
939 knownFrontends.put(frontend, new LeaderFrontendState.Disabled(persistenceId(), clientId, getDataStore()));
941 persistPayload(clientId, DisableTrackingPayload.create(clientId,
942 datastoreContext.getInitialPayloadSerializedBufferCapacity()), false);
946 private void updateSchemaContext(final UpdateSchemaContext message) {
947 updateSchemaContext(message.getEffectiveModelContext());
951 void updateSchemaContext(final @NonNull EffectiveModelContext schemaContext) {
952 store.updateSchemaContext(schemaContext);
955 private boolean isMetricsCaptureEnabled() {
956 CommonConfig config = new CommonConfig(getContext().system().settings().config());
957 return config.isMetricCaptureEnabled();
961 protected final RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
962 return snapshotCohort;
966 protected final RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
967 if (restoreFromSnapshot == null) {
968 return ShardRecoveryCoordinator.create(store, persistenceId(), LOG);
971 return ShardRecoveryCoordinator.forSnapshot(store, persistenceId(), LOG, restoreFromSnapshot.getSnapshot());
975 // non-final for testing
976 protected void onRecoveryComplete() {
977 restoreFromSnapshot = null;
979 //notify shard manager
980 getContext().parent().tell(new ActorInitialized(), getSelf());
982 // Being paranoid here - this method should only be called once but just in case...
983 if (txCommitTimeoutCheckSchedule == null) {
984 // Schedule a message to be periodically sent to check if the current in-progress
985 // transaction should be expired and aborted.
986 FiniteDuration period = FiniteDuration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
987 txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
988 period, period, getSelf(),
989 TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
994 protected final void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
995 if (data instanceof Payload) {
996 if (data instanceof DisableTrackingPayload) {
997 disableTracking((DisableTrackingPayload) data);
1002 store.applyReplicatedPayload(identifier, (Payload)data);
1003 } catch (DataValidationFailedException | IOException e) {
1004 LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
1007 LOG.error("{}: Unknown state for {} received {}", persistenceId(), identifier, data);
1012 protected final void onStateChanged() {
1013 boolean isLeader = isLeader();
1014 boolean hasLeader = hasLeader();
1015 treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
1017 // If this actor is no longer the leader close all the transaction chains
1019 if (LOG.isDebugEnabled()) {
1021 "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
1022 persistenceId(), getId());
1026 store.purgeLeaderState();
1029 if (hasLeader && !isIsolatedLeader()) {
1030 messageRetrySupport.retryMessages();
1035 protected final void onLeaderChanged(final String oldLeader, final String newLeader) {
1036 shardMBean.incrementLeadershipChangeCount();
1040 if (!knownFrontends.isEmpty()) {
1041 LOG.debug("{}: removing frontend state for {}", persistenceId(), knownFrontends.keySet());
1042 knownFrontends = ImmutableMap.of();
1045 requestMessageAssembler.close();
1048 // No leader anywhere, nothing else to do
1052 // Another leader was elected. If we were the previous leader and had pending transactions, convert
1053 // them to transaction messages and send to the new leader.
1054 ActorSelection leader = getLeader();
1055 if (leader != null) {
1056 // Clears all pending transactions and converts them to messages to be forwarded to a new leader.
1057 Collection<?> messagesToForward = commitCoordinator.convertPendingTransactionsToMessages(
1058 datastoreContext.getShardBatchedModificationCount());
1060 if (!messagesToForward.isEmpty()) {
1061 LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
1062 messagesToForward.size(), leader);
1064 for (Object message : messagesToForward) {
1065 LOG.debug("{}: Forwarding pending transaction message {}", persistenceId(), message);
1067 leader.tell(message, self());
1071 commitCoordinator.abortPendingTransactions("The transacton was aborted due to inflight leadership "
1072 + "change and the leader address isn't available.", this);
1075 // We have become the leader, we need to reconstruct frontend state
1076 knownFrontends = verifyNotNull(frontendMetadata.toLeaderState(this));
1077 LOG.debug("{}: became leader with frontend state for {}", persistenceId(), knownFrontends.keySet());
1080 if (!isIsolatedLeader()) {
1081 messageRetrySupport.retryMessages();
1086 protected final void pauseLeader(final Runnable operation) {
1087 LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
1090 // Tell-based protocol can replay transaction state, so it is safe to blow it up when we are paused.
1091 if (datastoreContext.isUseTellBasedProtocol()) {
1092 knownFrontends.values().forEach(LeaderFrontendState::retire);
1093 knownFrontends = ImmutableMap.of();
1096 store.setRunOnPendingTransactionsComplete(operation);
1100 protected final void unpauseLeader() {
1101 LOG.debug("{}: In unpauseLeader", persistenceId());
1104 store.setRunOnPendingTransactionsComplete(null);
1106 // Restore tell-based protocol state as if we were becoming the leader
1107 knownFrontends = verifyNotNull(frontendMetadata.toLeaderState(this));
1111 protected final OnDemandRaftState.AbstractBuilder<?, ?> newOnDemandRaftStateBuilder() {
1112 return OnDemandShardState.newBuilder()
1113 .treeChangeListenerActors(treeChangeSupport.getListenerActors())
1114 .commitCohortActors(store.getCohortActors());
1118 public final String persistenceId() {
1123 public final String journalPluginId() {
1124 // This method may be invoked from super constructor (wonderful), hence we also need to handle the case of
1125 // the field being uninitialized because our constructor is not finished.
1126 if (datastoreContext != null && !datastoreContext.isPersistent()) {
1127 return NON_PERSISTENT_JOURNAL_ID;
1129 return super.journalPluginId();
1133 final ShardCommitCoordinator getCommitCoordinator() {
1134 return commitCoordinator;
1137 // non-final for mocking
1138 DatastoreContext getDatastoreContext() {
1139 return datastoreContext;
1143 final ShardDataTree getDataStore() {
1148 // non-final for mocking
1149 ShardStats getShardMBean() {
1153 public static Builder builder() {
1154 return new Builder();
1157 public abstract static class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
1158 private final Class<? extends S> shardClass;
1159 private ShardIdentifier id;
1160 private Map<String, String> peerAddresses = Collections.emptyMap();
1161 private DatastoreContext datastoreContext;
1162 private EffectiveModelContextProvider schemaContextProvider;
1163 private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
1164 private DataTree dataTree;
1166 private volatile boolean sealed;
1168 AbstractBuilder(final Class<? extends S> shardClass) {
1169 this.shardClass = shardClass;
1172 final void checkSealed() {
1173 checkState(!sealed, "Builder is already sealed - further modifications are not allowed");
1176 @SuppressWarnings("unchecked")
1181 public T id(final ShardIdentifier newId) {
1187 public T peerAddresses(final Map<String, String> newPeerAddresses) {
1189 this.peerAddresses = newPeerAddresses;
1193 public T datastoreContext(final DatastoreContext newDatastoreContext) {
1195 this.datastoreContext = newDatastoreContext;
1199 public T schemaContextProvider(final EffectiveModelContextProvider newSchemaContextProvider) {
1201 this.schemaContextProvider = requireNonNull(newSchemaContextProvider);
1205 public T restoreFromSnapshot(final DatastoreSnapshot.ShardSnapshot newRestoreFromSnapshot) {
1207 this.restoreFromSnapshot = newRestoreFromSnapshot;
1211 public T dataTree(final DataTree newDataTree) {
1213 this.dataTree = newDataTree;
1217 public ShardIdentifier getId() {
1221 public Map<String, String> getPeerAddresses() {
1222 return peerAddresses;
1225 public DatastoreContext getDatastoreContext() {
1226 return datastoreContext;
1229 public EffectiveModelContext getSchemaContext() {
1230 return verifyNotNull(schemaContextProvider.getEffectiveModelContext());
1233 public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
1234 return restoreFromSnapshot;
1237 public DataTree getDataTree() {
1241 public TreeType getTreeType() {
1242 return switch (datastoreContext.getLogicalStoreType()) {
1243 case CONFIGURATION -> TreeType.CONFIGURATION;
1244 case OPERATIONAL -> TreeType.OPERATIONAL;
1248 protected void verify() {
1249 requireNonNull(id, "id should not be null");
1250 requireNonNull(peerAddresses, "peerAddresses should not be null");
1251 requireNonNull(datastoreContext, "dataStoreContext should not be null");
1252 requireNonNull(schemaContextProvider, "schemaContextProvider should not be null");
1255 public Props props() {
1258 return Props.create(shardClass, this);
1262 public static class Builder extends AbstractBuilder<Builder, Shard> {
1267 Builder(final Class<? extends Shard> shardClass) {
1273 return Ticker.systemTicker();
1276 void scheduleNextPendingTransaction() {
1277 self().tell(RESUME_NEXT_PENDING_TRANSACTION, ActorRef.noSender());