250e3f854f488049f33e6e87ba68baaf99797b46
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / Shard.java
1 /*
2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
3  *
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
7  */
8
9 package org.opendaylight.controller.cluster.datastore;
10
11 import akka.actor.ActorRef;
12 import akka.actor.ActorSelection;
13 import akka.actor.Cancellable;
14 import akka.actor.Props;
15 import akka.serialization.Serialization;
16 import com.google.common.annotations.VisibleForTesting;
17 import com.google.common.base.Optional;
18 import com.google.common.base.Preconditions;
19 import java.io.IOException;
20 import java.util.Collection;
21 import java.util.Collections;
22 import java.util.Map;
23 import java.util.concurrent.ExecutionException;
24 import java.util.concurrent.TimeUnit;
25 import javax.annotation.Nonnull;
26 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
27 import org.opendaylight.controller.cluster.common.actor.MessageTracker;
28 import org.opendaylight.controller.cluster.common.actor.MessageTracker.Error;
29 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
30 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
31 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
32 import org.opendaylight.controller.cluster.datastore.identifiers.ShardTransactionIdentifier;
33 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
34 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
35 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
36 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
37 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
38 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
39 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
40 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
41 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
42 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
43 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
44 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot;
45 import org.opendaylight.controller.cluster.datastore.messages.DatastoreSnapshot.ShardSnapshot;
46 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
47 import org.opendaylight.controller.cluster.datastore.messages.GetShardDataTree;
48 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
49 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
50 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
51 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
52 import org.opendaylight.controller.cluster.datastore.messages.ShardLeaderStateChanged;
53 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
54 import org.opendaylight.controller.cluster.datastore.modification.Modification;
55 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
56 import org.opendaylight.controller.cluster.datastore.utils.Dispatchers;
57 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
58 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
59 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
60 import org.opendaylight.controller.cluster.raft.RaftActor;
61 import org.opendaylight.controller.cluster.raft.RaftActorRecoveryCohort;
62 import org.opendaylight.controller.cluster.raft.RaftActorSnapshotCohort;
63 import org.opendaylight.controller.cluster.raft.RaftState;
64 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
65 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
66 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
67 import org.opendaylight.yangtools.concepts.Identifier;
68 import org.opendaylight.yangtools.util.StringIdentifier;
69 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
70 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
71 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
72 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
73 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
74 import scala.concurrent.duration.Duration;
75 import scala.concurrent.duration.FiniteDuration;
76
77 /**
78  * A Shard represents a portion of the logical data tree <br/>
79  * <p>
80  * Our Shard uses InMemoryDataTree as it's internal representation and delegates all requests it
81  * </p>
82  */
83 public class Shard extends RaftActor {
84
85     @VisibleForTesting
86     static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = new Object() {
87         @Override
88         public String toString() {
89             return "txCommitTimeoutCheck";
90         }
91     };
92
93     @VisibleForTesting
94     static final Object GET_SHARD_MBEAN_MESSAGE = new Object() {
95         @Override
96         public String toString() {
97             return "getShardMBeanMessage";
98         }
99     };
100
101     // FIXME: shard names should be encapsulated in their own class and this should be exposed as a constant.
102     public static final String DEFAULT_NAME = "default";
103
104     // The state of this Shard
105     private final ShardDataTree store;
106
107     /// The name of this shard
108     private final String name;
109
110     private final ShardStats shardMBean;
111
112     private DatastoreContext datastoreContext;
113
114     private final ShardCommitCoordinator commitCoordinator;
115
116     private long transactionCommitTimeout;
117
118     private Cancellable txCommitTimeoutCheckSchedule;
119
120     private final Optional<ActorRef> roleChangeNotifier;
121
122     private final MessageTracker appendEntriesReplyTracker;
123
124     private final ShardTransactionActorFactory transactionActorFactory;
125
126     private final ShardSnapshotCohort snapshotCohort;
127
128     private final DataTreeChangeListenerSupport treeChangeSupport = new DataTreeChangeListenerSupport(this);
129     private final DataChangeListenerSupport changeSupport = new DataChangeListenerSupport(this);
130
131
132     private ShardSnapshot restoreFromSnapshot;
133
134     private final ShardTransactionMessageRetrySupport messageRetrySupport;
135
136     protected Shard(AbstractBuilder<?, ?> builder) {
137         super(builder.getId().toString(), builder.getPeerAddresses(),
138                 Optional.of(builder.getDatastoreContext().getShardRaftConfig()), DataStoreVersions.CURRENT_VERSION);
139
140         this.name = builder.getId().toString();
141         this.datastoreContext = builder.getDatastoreContext();
142         this.restoreFromSnapshot = builder.getRestoreFromSnapshot();
143
144         setPersistence(datastoreContext.isPersistent());
145
146         LOG.info("Shard created : {}, persistent : {}", name, datastoreContext.isPersistent());
147
148         store = new ShardDataTree(builder.getSchemaContext(), builder.getTreeType(),
149                 new ShardDataTreeChangeListenerPublisherActorProxy(getContext(), name + "-DTCL-publisher"),
150                 new ShardDataChangeListenerPublisherActorProxy(getContext(), name + "-DCL-publisher"), name);
151
152         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
153                 datastoreContext.getDataStoreMXBeanType());
154         shardMBean.setShard(this);
155
156         if (isMetricsCaptureEnabled()) {
157             getContext().become(new MeteringBehavior(this));
158         }
159
160         commitCoordinator = new ShardCommitCoordinator(store,
161                 datastoreContext.getShardCommitQueueExpiryTimeoutInMillis(),
162                 datastoreContext.getShardTransactionCommitQueueCapacity(), LOG, this.name);
163
164         setTransactionCommitTimeout();
165
166         // create a notifier actor for each cluster member
167         roleChangeNotifier = createRoleChangeNotifier(name.toString());
168
169         appendEntriesReplyTracker = new MessageTracker(AppendEntriesReply.class,
170                 getRaftActorContext().getConfigParams().getIsolatedCheckIntervalInMillis());
171
172         transactionActorFactory = new ShardTransactionActorFactory(store, datastoreContext,
173                 new Dispatchers(context().system().dispatchers()).getDispatcherPath(
174                         Dispatchers.DispatcherType.Transaction), self(), getContext(), shardMBean);
175
176         snapshotCohort = new ShardSnapshotCohort(transactionActorFactory, store, LOG, this.name);
177
178         messageRetrySupport = new ShardTransactionMessageRetrySupport(this);
179     }
180
181     private void setTransactionCommitTimeout() {
182         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
183                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS) / 2;
184     }
185
186     private Optional<ActorRef> createRoleChangeNotifier(String shardId) {
187         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
188             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
189         return Optional.of(shardRoleChangeNotifier);
190     }
191
192     @Override
193     public void postStop() {
194         LOG.info("Stopping Shard {}", persistenceId());
195
196         super.postStop();
197
198         messageRetrySupport.close();
199
200         if(txCommitTimeoutCheckSchedule != null) {
201             txCommitTimeoutCheckSchedule.cancel();
202         }
203
204         commitCoordinator.abortPendingTransactions("Transaction aborted due to shutdown.", this);
205
206         shardMBean.unregisterMBean();
207     }
208
209     @Override
210     protected void handleRecover(final Object message) {
211         LOG.debug("{}: onReceiveRecover: Received message {} from {}", persistenceId(), message.getClass(),
212             getSender());
213
214         super.handleRecover(message);
215         if (LOG.isTraceEnabled()) {
216             appendEntriesReplyTracker.begin();
217         }
218     }
219
220     @Override
221     protected void handleNonRaftCommand(final Object message) {
222         try (final MessageTracker.Context context = appendEntriesReplyTracker.received(message)) {
223             final Optional<Error> maybeError = context.error();
224             if (maybeError.isPresent()) {
225                 LOG.trace("{} : AppendEntriesReply failed to arrive at the expected interval {}", persistenceId(),
226                     maybeError.get());
227             }
228
229             if (CreateTransaction.isSerializedType(message)) {
230                 handleCreateTransaction(message);
231             } else if (message instanceof BatchedModifications) {
232                 handleBatchedModifications((BatchedModifications)message);
233             } else if (message instanceof ForwardedReadyTransaction) {
234                 handleForwardedReadyTransaction((ForwardedReadyTransaction) message);
235             } else if (message instanceof ReadyLocalTransaction) {
236                 handleReadyLocalTransaction((ReadyLocalTransaction)message);
237             } else if (CanCommitTransaction.isSerializedType(message)) {
238                 handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
239             } else if (CommitTransaction.isSerializedType(message)) {
240                 handleCommitTransaction(CommitTransaction.fromSerializable(message));
241             } else if (AbortTransaction.isSerializedType(message)) {
242                 handleAbortTransaction(AbortTransaction.fromSerializable(message));
243             } else if (CloseTransactionChain.isSerializedType(message)) {
244                 closeTransactionChain(CloseTransactionChain.fromSerializable(message));
245             } else if (message instanceof RegisterChangeListener) {
246                 changeSupport.onMessage((RegisterChangeListener) message, isLeader(), hasLeader());
247             } else if (message instanceof RegisterDataTreeChangeListener) {
248                 treeChangeSupport.onMessage((RegisterDataTreeChangeListener) message, isLeader(), hasLeader());
249             } else if (message instanceof UpdateSchemaContext) {
250                 updateSchemaContext((UpdateSchemaContext) message);
251             } else if (message instanceof PeerAddressResolved) {
252                 PeerAddressResolved resolved = (PeerAddressResolved) message;
253                 setPeerAddress(resolved.getPeerId().toString(),
254                         resolved.getPeerAddress());
255             } else if (TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
256                 commitCoordinator.checkForExpiredTransactions(transactionCommitTimeout, this);
257             } else if(message instanceof DatastoreContext) {
258                 onDatastoreContext((DatastoreContext)message);
259             } else if(message instanceof RegisterRoleChangeListener){
260                 roleChangeNotifier.get().forward(message, context());
261             } else if (message instanceof FollowerInitialSyncUpStatus) {
262                 shardMBean.setFollowerInitialSyncStatus(((FollowerInitialSyncUpStatus) message).isInitialSyncDone());
263                 context().parent().tell(message, self());
264             } else if(GET_SHARD_MBEAN_MESSAGE.equals(message)){
265                 sender().tell(getShardMBean(), self());
266             } else if(message instanceof GetShardDataTree) {
267                 sender().tell(store.getDataTree(), self());
268             } else if(message instanceof ServerRemoved){
269                 context().parent().forward(message, context());
270             } else if(ShardTransactionMessageRetrySupport.TIMER_MESSAGE_CLASS.isInstance(message)) {
271                 messageRetrySupport.onTimerMessage(message);
272             } else if (message instanceof DataTreeCohortActorRegistry.CohortRegistryCommand) {
273                 commitCoordinator.processCohortRegistryCommand(getSender(),
274                         (DataTreeCohortActorRegistry.CohortRegistryCommand) message);
275             } else {
276                 super.handleNonRaftCommand(message);
277             }
278         }
279     }
280
281     private boolean hasLeader() {
282         return getLeaderId() != null;
283     }
284
285     public int getPendingTxCommitQueueSize() {
286         return commitCoordinator.getQueueSize();
287     }
288
289     public int getCohortCacheSize() {
290         return commitCoordinator.getCohortCacheSize();
291     }
292
293     @Override
294     protected Optional<ActorRef> getRoleChangeNotifier() {
295         return roleChangeNotifier;
296     }
297
298     @Override
299     protected LeaderStateChanged newLeaderStateChanged(String memberId, String leaderId, short leaderPayloadVersion) {
300         return isLeader() ? new ShardLeaderStateChanged(memberId, leaderId, store.getDataTree(), leaderPayloadVersion)
301                 : new ShardLeaderStateChanged(memberId, leaderId, leaderPayloadVersion);
302     }
303
304     protected void onDatastoreContext(DatastoreContext context) {
305         datastoreContext = context;
306
307         commitCoordinator.setQueueCapacity(datastoreContext.getShardTransactionCommitQueueCapacity());
308
309         setTransactionCommitTimeout();
310
311         if(datastoreContext.isPersistent() && !persistence().isRecoveryApplicable()) {
312             setPersistence(true);
313         } else if(!datastoreContext.isPersistent() && persistence().isRecoveryApplicable()) {
314             setPersistence(false);
315         }
316
317         updateConfigParams(datastoreContext.getShardRaftConfig());
318     }
319
320     private static boolean isEmptyCommit(final DataTreeCandidate candidate) {
321         return ModificationType.UNMODIFIED.equals(candidate.getRootNode().getModificationType());
322     }
323
324     void continueCommit(final CohortEntry cohortEntry) {
325         final DataTreeCandidate candidate = cohortEntry.getCandidate();
326
327         // If we do not have any followers and we are not using persistence
328         // or if cohortEntry has no modifications
329         // we can apply modification to the state immediately
330         if ((!hasFollowers() && !persistence().isRecoveryApplicable()) || isEmptyCommit(candidate)) {
331             applyModificationToState(cohortEntry.getReplySender(), cohortEntry.getTransactionID(), candidate);
332         } else {
333             persistData(cohortEntry.getReplySender(), cohortEntry.getTransactionID(),
334                     DataTreeCandidatePayload.create(candidate));
335         }
336     }
337
338     private void handleCommitTransaction(final CommitTransaction commit) {
339         if (isLeader()) {
340             if(!commitCoordinator.handleCommit(new StringIdentifier(commit.getTransactionID()), getSender(), this)) {
341                 shardMBean.incrementFailedTransactionsCount();
342             }
343         } else {
344             ActorSelection leader = getLeader();
345             if (leader == null) {
346                 messageRetrySupport.addMessageToRetry(commit, getSender(),
347                         "Could not commit transaction " + commit.getTransactionID());
348             } else {
349                 LOG.debug("{}: Forwarding CommitTransaction to leader {}", persistenceId(), leader);
350                 leader.forward(commit, getContext());
351             }
352         }
353     }
354
355     private void finishCommit(@Nonnull final ActorRef sender, @Nonnull final Identifier transactionID,
356             @Nonnull final CohortEntry cohortEntry) {
357         LOG.debug("{}: Finishing commit for transaction {}", persistenceId(), cohortEntry.getTransactionID());
358
359         try {
360             try {
361             cohortEntry.commit();
362             } catch(ExecutionException e) {
363                 // We may get a "store tree and candidate base differ" IllegalStateException from commit under
364                 // certain edge case scenarios so we'll try to re-apply the candidate from scratch as a last
365                 // resort. Eg, we're a follower and a tx payload is replicated but the leader goes down before
366                 // applying it to the state. We then become the leader and a second tx is pre-committed and
367                 // replicated. When consensus occurs, this will cause the first tx to be applied as a foreign
368                 // candidate via applyState prior to the second tx. Since the second tx has already been
369                 // pre-committed, when it gets here to commit it will get an IllegalStateException.
370
371                 // FIXME - this is not an ideal way to handle this scenario. This is temporary - a cleaner
372                 // solution will be forthcoming.
373                 if(e.getCause() instanceof IllegalStateException) {
374                     LOG.debug("{}: commit failed for transaction {} - retrying as foreign candidate", persistenceId(),
375                             transactionID, e);
376                     store.applyForeignCandidate(transactionID, cohortEntry.getCandidate());
377                 } else {
378                     throw e;
379                 }
380             }
381
382             sender.tell(CommitTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(), getSelf());
383
384             shardMBean.incrementCommittedTransactionCount();
385             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
386
387         } catch (Exception e) {
388             sender.tell(new akka.actor.Status.Failure(e), getSelf());
389
390             LOG.error("{}, An exception occurred while committing transaction {}", persistenceId(),
391                     transactionID, e);
392             shardMBean.incrementFailedTransactionsCount();
393         } finally {
394             commitCoordinator.currentTransactionComplete(transactionID, true);
395         }
396     }
397
398     private void finishCommit(@Nonnull final ActorRef sender, final @Nonnull Identifier transactionID) {
399         // With persistence enabled, this method is called via applyState by the leader strategy
400         // after the commit has been replicated to a majority of the followers.
401
402         CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
403         if (cohortEntry == null) {
404             // The transaction is no longer the current commit. This can happen if the transaction
405             // was aborted prior, most likely due to timeout in the front-end. We need to finish
406             // committing the transaction though since it was successfully persisted and replicated
407             // however we can't use the original cohort b/c it was already preCommitted and may
408             // conflict with the current commit or may have been aborted so we commit with a new
409             // transaction.
410             cohortEntry = commitCoordinator.getAndRemoveCohortEntry(transactionID);
411             if(cohortEntry != null) {
412                 try {
413                     store.applyForeignCandidate(transactionID, cohortEntry.getCandidate());
414                 } catch (DataValidationFailedException e) {
415                     shardMBean.incrementFailedTransactionsCount();
416                     LOG.error("{}: Failed to re-apply transaction {}", persistenceId(), transactionID, e);
417                 }
418
419                 sender.tell(CommitTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(),
420                         getSelf());
421             } else {
422                 // This really shouldn't happen - it likely means that persistence or replication
423                 // took so long to complete such that the cohort entry was expired from the cache.
424                 IllegalStateException ex = new IllegalStateException(
425                         String.format("%s: Could not finish committing transaction %s - no CohortEntry found",
426                                 persistenceId(), transactionID));
427                 LOG.error(ex.getMessage());
428                 sender.tell(new akka.actor.Status.Failure(ex), getSelf());
429             }
430         } else {
431             finishCommit(sender, transactionID, cohortEntry);
432         }
433     }
434
435     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
436         LOG.debug("{}: Can committing transaction {}", persistenceId(), canCommit.getTransactionID());
437
438         if (isLeader()) {
439         commitCoordinator.handleCanCommit(new StringIdentifier(canCommit.getTransactionID()), getSender(), this);
440         } else {
441             ActorSelection leader = getLeader();
442             if (leader == null) {
443                 messageRetrySupport.addMessageToRetry(canCommit, getSender(),
444                         "Could not canCommit transaction " + canCommit.getTransactionID());
445             } else {
446                 LOG.debug("{}: Forwarding CanCommitTransaction to leader {}", persistenceId(), leader);
447                 leader.forward(canCommit, getContext());
448             }
449         }
450     }
451
452     protected void handleBatchedModificationsLocal(BatchedModifications batched, ActorRef sender) {
453         try {
454             commitCoordinator.handleBatchedModifications(batched, sender, this, store.getSchemaContext());
455         } catch (Exception e) {
456             LOG.error("{}: Error handling BatchedModifications for Tx {}", persistenceId(),
457                     batched.getTransactionID(), e);
458             sender.tell(new akka.actor.Status.Failure(e), getSelf());
459         }
460     }
461
462     private void handleBatchedModifications(BatchedModifications batched) {
463         // This message is sent to prepare the modifications transaction directly on the Shard as an
464         // optimization to avoid the extra overhead of a separate ShardTransaction actor. On the last
465         // BatchedModifications message, the caller sets the ready flag in the message indicating
466         // modifications are complete. The reply contains the cohort actor path (this actor) for the caller
467         // to initiate the 3-phase commit. This also avoids the overhead of sending an additional
468         // ReadyTransaction message.
469
470         // If we're not the leader then forward to the leader. This is a safety measure - we shouldn't
471         // normally get here if we're not the leader as the front-end (TransactionProxy) should determine
472         // the primary/leader shard. However with timing and caching on the front-end, there's a small
473         // window where it could have a stale leader during leadership transitions.
474         //
475         boolean isLeaderActive = isLeaderActive();
476         if (isLeader() && isLeaderActive) {
477             handleBatchedModificationsLocal(batched, getSender());
478         } else {
479             ActorSelection leader = getLeader();
480             if (!isLeaderActive || leader == null) {
481                 messageRetrySupport.addMessageToRetry(batched, getSender(),
482                         "Could not commit transaction " + batched.getTransactionID());
483             } else {
484                 // If this is not the first batch and leadership changed in between batched messages,
485                 // we need to reconstruct previous BatchedModifications from the transaction
486                 // DataTreeModification, honoring the max batched modification count, and forward all the
487                 // previous BatchedModifications to the new leader.
488                 Collection<BatchedModifications> newModifications = commitCoordinator.createForwardedBatchedModifications(
489                         batched, datastoreContext.getShardBatchedModificationCount());
490
491                 LOG.debug("{}: Forwarding {} BatchedModifications to leader {}", persistenceId(),
492                         newModifications.size(), leader);
493
494                 for(BatchedModifications bm: newModifications) {
495                     leader.forward(bm, getContext());
496                 }
497             }
498         }
499     }
500
501     private boolean failIfIsolatedLeader(ActorRef sender) {
502         if(isIsolatedLeader()) {
503             sender.tell(new akka.actor.Status.Failure(new NoShardLeaderException(String.format(
504                     "Shard %s was the leader but has lost contact with all of its followers. Either all" +
505                     " other follower nodes are down or this node is isolated by a network partition.",
506                     persistenceId()))), getSelf());
507             return true;
508         }
509
510         return false;
511     }
512
513     protected boolean isIsolatedLeader() {
514         return getRaftState() == RaftState.IsolatedLeader;
515     }
516
517     private void handleReadyLocalTransaction(final ReadyLocalTransaction message) {
518         LOG.debug("{}: handleReadyLocalTransaction for {}", persistenceId(), message.getTransactionID());
519
520         boolean isLeaderActive = isLeaderActive();
521         if (isLeader() && isLeaderActive) {
522             try {
523                 commitCoordinator.handleReadyLocalTransaction(message, getSender(), this, store.getSchemaContext());
524             } catch (Exception e) {
525                 LOG.error("{}: Error handling ReadyLocalTransaction for Tx {}", persistenceId(),
526                         message.getTransactionID(), e);
527                 getSender().tell(new akka.actor.Status.Failure(e), getSelf());
528             }
529         } else {
530             ActorSelection leader = getLeader();
531             if (!isLeaderActive || leader == null) {
532                 messageRetrySupport.addMessageToRetry(message, getSender(),
533                         "Could not commit transaction " + message.getTransactionID());
534             } else {
535                 LOG.debug("{}: Forwarding ReadyLocalTransaction to leader {}", persistenceId(), leader);
536                 message.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
537                 leader.forward(message, getContext());
538             }
539         }
540     }
541
542     private void handleForwardedReadyTransaction(ForwardedReadyTransaction forwardedReady) {
543         LOG.debug("{}: handleForwardedReadyTransaction for {}", persistenceId(), forwardedReady.getTransactionID());
544
545         boolean isLeaderActive = isLeaderActive();
546         if (isLeader() && isLeaderActive) {
547             commitCoordinator.handleForwardedReadyTransaction(forwardedReady, getSender(), this,
548                     store.getSchemaContext());
549         } else {
550             ActorSelection leader = getLeader();
551             if (!isLeaderActive || leader == null) {
552                 messageRetrySupport.addMessageToRetry(forwardedReady, getSender(),
553                         "Could not commit transaction " + forwardedReady.getTransactionID());
554             } else {
555                 LOG.debug("{}: Forwarding ForwardedReadyTransaction to leader {}", persistenceId(), leader);
556
557                 ReadyLocalTransaction readyLocal = new ReadyLocalTransaction(forwardedReady.getTransactionID(),
558                         forwardedReady.getTransaction().getSnapshot(), forwardedReady.isDoImmediateCommit());
559                 readyLocal.setRemoteVersion(getCurrentBehavior().getLeaderPayloadVersion());
560                 leader.forward(readyLocal, getContext());
561             }
562         }
563     }
564
565     private void handleAbortTransaction(final AbortTransaction abort) {
566         doAbortTransaction(abort.getTransactionID(), getSender());
567     }
568
569     void doAbortTransaction(final String transactionID, final ActorRef sender) {
570         commitCoordinator.handleAbort(new StringIdentifier(transactionID), sender, this);
571     }
572
573     private void handleCreateTransaction(final Object message) {
574         if (isLeader()) {
575             createTransaction(CreateTransaction.fromSerializable(message));
576         } else if (getLeader() != null) {
577             getLeader().forward(message, getContext());
578         } else {
579             getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(
580                     "Could not create a shard transaction", persistenceId())), getSelf());
581         }
582     }
583
584     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
585         store.closeTransactionChain(closeTransactionChain.getTransactionChainId());
586     }
587
588     private void createTransaction(CreateTransaction createTransaction) {
589         try {
590             if(TransactionType.fromInt(createTransaction.getTransactionType()) != TransactionType.READ_ONLY &&
591                     failIfIsolatedLeader(getSender())) {
592                 return;
593             }
594
595             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
596                 createTransaction.getTransactionId(), createTransaction.getTransactionChainId());
597
598             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
599                     createTransaction.getTransactionId(), createTransaction.getVersion()).toSerializable(), getSelf());
600         } catch (Exception e) {
601             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
602         }
603     }
604
605     private ActorRef createTransaction(int transactionType, String remoteTransactionId, String transactionChainId) {
606         ShardTransactionIdentifier transactionId = new ShardTransactionIdentifier(remoteTransactionId);
607         LOG.debug("{}: Creating transaction : {} ", persistenceId(), transactionId);
608         return transactionActorFactory.newShardTransaction(TransactionType.fromInt(transactionType),
609             transactionId, transactionChainId);
610     }
611
612     private void commitWithNewTransaction(final Modification modification) {
613         ReadWriteShardDataTreeTransaction tx = store.newReadWriteTransaction(modification.toString(), null);
614         modification.apply(tx.getSnapshot());
615         try {
616             snapshotCohort.syncCommitTransaction(tx);
617             shardMBean.incrementCommittedTransactionCount();
618             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
619         } catch (Exception e) {
620             shardMBean.incrementFailedTransactionsCount();
621             LOG.error("{}: Failed to commit", persistenceId(), e);
622         }
623     }
624
625     private void updateSchemaContext(final UpdateSchemaContext message) {
626         updateSchemaContext(message.getSchemaContext());
627     }
628
629     @VisibleForTesting
630     void updateSchemaContext(final SchemaContext schemaContext) {
631         store.updateSchemaContext(schemaContext);
632     }
633
634     private boolean isMetricsCaptureEnabled() {
635         CommonConfig config = new CommonConfig(getContext().system().settings().config());
636         return config.isMetricCaptureEnabled();
637     }
638
639     @Override
640     @VisibleForTesting
641     public RaftActorSnapshotCohort getRaftActorSnapshotCohort() {
642         return snapshotCohort;
643     }
644
645     @Override
646     @Nonnull
647     protected RaftActorRecoveryCohort getRaftActorRecoveryCohort() {
648         return new ShardRecoveryCoordinator(store, store.getSchemaContext(),
649                 restoreFromSnapshot != null ? restoreFromSnapshot.getSnapshot() : null, persistenceId(), LOG);
650     }
651
652     @Override
653     protected void onRecoveryComplete() {
654         restoreFromSnapshot = null;
655
656         //notify shard manager
657         getContext().parent().tell(new ActorInitialized(), getSelf());
658
659         // Being paranoid here - this method should only be called once but just in case...
660         if(txCommitTimeoutCheckSchedule == null) {
661             // Schedule a message to be periodically sent to check if the current in-progress
662             // transaction should be expired and aborted.
663             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
664             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
665                     period, period, getSelf(),
666                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
667         }
668     }
669
670     @Override
671     protected void applyState(final ActorRef clientActor, final Identifier identifier, final Object data) {
672         if (data instanceof DataTreeCandidatePayload) {
673             if (clientActor == null) {
674                 // No clientActor indicates a replica coming from the leader
675                 try {
676                     store.applyForeignCandidate(identifier, ((DataTreeCandidatePayload)data).getCandidate());
677                 } catch (DataValidationFailedException | IOException e) {
678                     LOG.error("{}: Error applying replica {}", persistenceId(), identifier, e);
679                 }
680             } else {
681                 // Replication consensus reached, proceed to commit
682                 finishCommit(clientActor, identifier);
683             }
684         } else {
685             LOG.error("{}: Unknown state received {} ClassLoader {}", persistenceId(), data,
686                 data.getClass().getClassLoader());
687         }
688     }
689
690     private void applyModificationToState(ActorRef clientActor, Identifier identifier, Object modification) {
691         if(modification == null) {
692             LOG.error(
693                     "{}: modification is null - this is very unexpected, clientActor = {}, identifier = {}",
694                     persistenceId(), identifier, clientActor != null ? clientActor.path().toString() : null);
695         } else if(clientActor == null) {
696             // There's no clientActor to which to send a commit reply so we must be applying
697             // replicated state from the leader.
698             commitWithNewTransaction(MutableCompositeModification.fromSerializable(modification));
699         } else {
700             // This must be the OK to commit after replication consensus.
701             finishCommit(clientActor, identifier);
702         }
703     }
704
705     @Override
706     protected void onStateChanged() {
707         boolean isLeader = isLeader();
708         boolean hasLeader = hasLeader();
709         changeSupport.onLeadershipChange(isLeader, hasLeader);
710         treeChangeSupport.onLeadershipChange(isLeader, hasLeader);
711
712         // If this actor is no longer the leader close all the transaction chains
713         if (!isLeader) {
714             if(LOG.isDebugEnabled()) {
715                 LOG.debug(
716                     "{}: onStateChanged: Closing all transaction chains because shard {} is no longer the leader",
717                     persistenceId(), getId());
718             }
719
720             store.closeAllTransactionChains();
721         }
722
723         if(hasLeader && !isIsolatedLeader()) {
724             messageRetrySupport.retryMessages();
725         }
726     }
727
728     @Override
729     protected void onLeaderChanged(String oldLeader, String newLeader) {
730         shardMBean.incrementLeadershipChangeCount();
731
732         boolean hasLeader = hasLeader();
733         if(hasLeader && !isLeader()) {
734             // Another leader was elected. If we were the previous leader and had pending transactions, convert
735             // them to transaction messages and send to the new leader.
736             ActorSelection leader = getLeader();
737             if(leader != null) {
738                 Collection<Object> messagesToForward = commitCoordinator.convertPendingTransactionsToMessages(
739                         datastoreContext.getShardBatchedModificationCount());
740
741                 if(!messagesToForward.isEmpty()) {
742                     LOG.debug("{}: Forwarding {} pending transaction messages to leader {}", persistenceId(),
743                             messagesToForward.size(), leader);
744
745                     for(Object message: messagesToForward) {
746                         leader.tell(message, self());
747                     }
748                 }
749             } else {
750                 commitCoordinator.abortPendingTransactions(
751                         "The transacton was aborted due to inflight leadership change and the leader address isn't available.",
752                         this);
753             }
754         }
755
756         if(hasLeader && !isIsolatedLeader()) {
757             messageRetrySupport.retryMessages();
758         }
759     }
760
761     @Override
762     protected void pauseLeader(Runnable operation) {
763         LOG.debug("{}: In pauseLeader, operation: {}", persistenceId(), operation);
764         commitCoordinator.setRunOnPendingTransactionsComplete(operation);
765     }
766
767     @Override
768     public String persistenceId() {
769         return this.name;
770     }
771
772     @VisibleForTesting
773     ShardCommitCoordinator getCommitCoordinator() {
774         return commitCoordinator;
775     }
776
777     public DatastoreContext getDatastoreContext() {
778         return datastoreContext;
779     }
780
781     @VisibleForTesting
782     public ShardDataTree getDataStore() {
783         return store;
784     }
785
786     @VisibleForTesting
787     ShardStats getShardMBean() {
788         return shardMBean;
789     }
790
791     public static Builder builder() {
792         return new Builder();
793     }
794
795     public static abstract class AbstractBuilder<T extends AbstractBuilder<T, S>, S extends Shard> {
796         private final Class<S> shardClass;
797         private ShardIdentifier id;
798         private Map<String, String> peerAddresses = Collections.emptyMap();
799         private DatastoreContext datastoreContext;
800         private SchemaContext schemaContext;
801         private DatastoreSnapshot.ShardSnapshot restoreFromSnapshot;
802         private volatile boolean sealed;
803
804         protected AbstractBuilder(Class<S> shardClass) {
805             this.shardClass = shardClass;
806         }
807
808         protected void checkSealed() {
809             Preconditions.checkState(!sealed, "Builder isalready sealed - further modifications are not allowed");
810         }
811
812         @SuppressWarnings("unchecked")
813         private T self() {
814             return (T) this;
815         }
816
817         public T id(ShardIdentifier id) {
818             checkSealed();
819             this.id = id;
820             return self();
821         }
822
823         public T peerAddresses(Map<String, String> peerAddresses) {
824             checkSealed();
825             this.peerAddresses = peerAddresses;
826             return self();
827         }
828
829         public T datastoreContext(DatastoreContext datastoreContext) {
830             checkSealed();
831             this.datastoreContext = datastoreContext;
832             return self();
833         }
834
835         public T schemaContext(SchemaContext schemaContext) {
836             checkSealed();
837             this.schemaContext = schemaContext;
838             return self();
839         }
840
841         public T restoreFromSnapshot(DatastoreSnapshot.ShardSnapshot restoreFromSnapshot) {
842             checkSealed();
843             this.restoreFromSnapshot = restoreFromSnapshot;
844             return self();
845         }
846
847         public ShardIdentifier getId() {
848             return id;
849         }
850
851         public Map<String, String> getPeerAddresses() {
852             return peerAddresses;
853         }
854
855         public DatastoreContext getDatastoreContext() {
856             return datastoreContext;
857         }
858
859         public SchemaContext getSchemaContext() {
860             return schemaContext;
861         }
862
863         public DatastoreSnapshot.ShardSnapshot getRestoreFromSnapshot() {
864             return restoreFromSnapshot;
865         }
866
867         public TreeType getTreeType() {
868             switch (datastoreContext.getLogicalStoreType()) {
869             case CONFIGURATION:
870                 return TreeType.CONFIGURATION;
871             case OPERATIONAL:
872                 return TreeType.OPERATIONAL;
873             }
874
875             throw new IllegalStateException("Unhandled logical store type " + datastoreContext.getLogicalStoreType());
876         }
877
878         protected void verify() {
879             Preconditions.checkNotNull(id, "id should not be null");
880             Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
881             Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
882             Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
883         }
884
885         public Props props() {
886             sealed = true;
887             verify();
888             return Props.create(shardClass, this);
889         }
890     }
891
892     public static class Builder extends AbstractBuilder<Builder, Shard> {
893         private Builder() {
894             super(Shard.class);
895         }
896     }
897 }