Split out TransactionContext classes
[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.PoisonPill;
15 import akka.actor.Props;
16 import akka.event.Logging;
17 import akka.event.LoggingAdapter;
18 import akka.japi.Creator;
19 import akka.persistence.RecoveryFailure;
20 import akka.serialization.Serialization;
21 import com.google.common.annotations.VisibleForTesting;
22 import com.google.common.base.Optional;
23 import com.google.common.base.Preconditions;
24 import com.google.common.collect.Lists;
25 import com.google.common.util.concurrent.FutureCallback;
26 import com.google.common.util.concurrent.Futures;
27 import com.google.common.util.concurrent.ListenableFuture;
28 import com.google.protobuf.ByteString;
29 import com.google.protobuf.InvalidProtocolBufferException;
30 import java.util.Collection;
31 import java.util.HashMap;
32 import java.util.List;
33 import java.util.Map;
34 import java.util.concurrent.ExecutionException;
35 import java.util.concurrent.TimeUnit;
36 import javax.annotation.Nonnull;
37 import org.opendaylight.controller.cluster.DataPersistenceProvider;
38 import org.opendaylight.controller.cluster.common.actor.CommonConfig;
39 import org.opendaylight.controller.cluster.common.actor.MeteringBehavior;
40 import org.opendaylight.controller.cluster.datastore.ShardCommitCoordinator.CohortEntry;
41 import org.opendaylight.controller.cluster.datastore.compat.BackwardsCompatibleThreePhaseCommitCohort;
42 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
43 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
44 import org.opendaylight.controller.cluster.datastore.identifiers.ShardTransactionIdentifier;
45 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardMBeanFactory;
46 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
47 import org.opendaylight.controller.cluster.datastore.messages.AbortTransaction;
48 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
49 import org.opendaylight.controller.cluster.datastore.messages.ActorInitialized;
50 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
51 import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
52 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
53 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
54 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
55 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
56 import org.opendaylight.controller.cluster.datastore.messages.EnableNotification;
57 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
58 import org.opendaylight.controller.cluster.datastore.messages.PeerAddressResolved;
59 import org.opendaylight.controller.cluster.datastore.messages.ReadData;
60 import org.opendaylight.controller.cluster.datastore.messages.ReadDataReply;
61 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
62 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
63 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListenerReply;
64 import org.opendaylight.controller.cluster.datastore.messages.UpdateSchemaContext;
65 import org.opendaylight.controller.cluster.datastore.modification.Modification;
66 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
67 import org.opendaylight.controller.cluster.datastore.node.NormalizedNodeToNodeCodec;
68 import org.opendaylight.controller.cluster.notifications.RoleChangeNotifier;
69 import org.opendaylight.controller.cluster.raft.RaftActor;
70 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
71 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
72 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationByteStringPayload;
73 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.CompositeModificationPayload;
74 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
75 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
76 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStore;
77 import org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStoreFactory;
78 import org.opendaylight.controller.protobuff.messages.common.NormalizedNodeMessages;
79 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
80 import org.opendaylight.controller.sal.core.spi.data.DOMStoreTransactionChain;
81 import org.opendaylight.controller.sal.core.spi.data.DOMStoreTransactionFactory;
82 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
83 import org.opendaylight.yangtools.concepts.ListenerRegistration;
84 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
85 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
86 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
87 import scala.concurrent.duration.Duration;
88 import scala.concurrent.duration.FiniteDuration;
89
90 /**
91  * A Shard represents a portion of the logical data tree <br/>
92  * <p>
93  * Our Shard uses InMemoryDataStore as it's internal representation and delegates all requests it
94  * </p>
95  */
96 public class Shard extends RaftActor {
97
98     private static final Object TX_COMMIT_TIMEOUT_CHECK_MESSAGE = "txCommitTimeoutCheck";
99
100     @VisibleForTesting
101     static final String DEFAULT_NAME = "default";
102
103     // The state of this Shard
104     private final InMemoryDOMDataStore store;
105
106     private final LoggingAdapter LOG =
107         Logging.getLogger(getContext().system(), this);
108
109     /// The name of this shard
110     private final ShardIdentifier name;
111
112     private final ShardStats shardMBean;
113
114     private final List<ActorSelection> dataChangeListeners =  Lists.newArrayList();
115
116     private final List<DelayedListenerRegistration> delayedListenerRegistrations =
117                                                                        Lists.newArrayList();
118
119     private final DatastoreContext datastoreContext;
120
121     private final DataPersistenceProvider dataPersistenceProvider;
122
123     private SchemaContext schemaContext;
124
125     private ActorRef createSnapshotTransaction;
126
127     private int createSnapshotTransactionCounter;
128
129     private final ShardCommitCoordinator commitCoordinator;
130
131     private final long transactionCommitTimeout;
132
133     private Cancellable txCommitTimeoutCheckSchedule;
134
135     private final Optional<ActorRef> roleChangeNotifier;
136
137     /**
138      * Coordinates persistence recovery on startup.
139      */
140     private ShardRecoveryCoordinator recoveryCoordinator;
141     private List<Object> currentLogRecoveryBatch;
142
143     private final Map<String, DOMStoreTransactionChain> transactionChains = new HashMap<>();
144
145     protected Shard(final ShardIdentifier name, final Map<ShardIdentifier, String> peerAddresses,
146             final DatastoreContext datastoreContext, final SchemaContext schemaContext) {
147         super(name.toString(), mapPeerAddresses(peerAddresses),
148                 Optional.of(datastoreContext.getShardRaftConfig()));
149
150         this.name = name;
151         this.datastoreContext = datastoreContext;
152         this.schemaContext = schemaContext;
153         this.dataPersistenceProvider = (datastoreContext.isPersistent()) ? new PersistentDataProvider() : new NonPersistentRaftDataProvider();
154
155         LOG.info("Shard created : {} persistent : {}", name, datastoreContext.isPersistent());
156
157         store = InMemoryDOMDataStoreFactory.create(name.toString(), null,
158                 datastoreContext.getDataStoreProperties());
159
160         if(schemaContext != null) {
161             store.onGlobalContextUpdated(schemaContext);
162         }
163
164         shardMBean = ShardMBeanFactory.getShardStatsMBean(name.toString(),
165                 datastoreContext.getDataStoreMXBeanType());
166         shardMBean.setNotificationManager(store.getDataChangeListenerNotificationManager());
167
168         if (isMetricsCaptureEnabled()) {
169             getContext().become(new MeteringBehavior(this));
170         }
171
172         commitCoordinator = new ShardCommitCoordinator(TimeUnit.SECONDS.convert(1, TimeUnit.MINUTES),
173                 datastoreContext.getShardTransactionCommitQueueCapacity());
174
175         transactionCommitTimeout = TimeUnit.MILLISECONDS.convert(
176                 datastoreContext.getShardTransactionCommitTimeoutInSeconds(), TimeUnit.SECONDS);
177
178         // create a notifier actor for each cluster member
179         roleChangeNotifier = createRoleChangeNotifier(name.toString());
180     }
181
182     private static Map<String, String> mapPeerAddresses(
183         final Map<ShardIdentifier, String> peerAddresses) {
184         Map<String, String> map = new HashMap<>();
185
186         for (Map.Entry<ShardIdentifier, String> entry : peerAddresses
187             .entrySet()) {
188             map.put(entry.getKey().toString(), entry.getValue());
189         }
190
191         return map;
192     }
193
194     public static Props props(final ShardIdentifier name,
195         final Map<ShardIdentifier, String> peerAddresses,
196         final DatastoreContext datastoreContext, final SchemaContext schemaContext) {
197         Preconditions.checkNotNull(name, "name should not be null");
198         Preconditions.checkNotNull(peerAddresses, "peerAddresses should not be null");
199         Preconditions.checkNotNull(datastoreContext, "dataStoreContext should not be null");
200         Preconditions.checkNotNull(schemaContext, "schemaContext should not be null");
201
202         return Props.create(new ShardCreator(name, peerAddresses, datastoreContext, schemaContext));
203     }
204
205     private Optional<ActorRef> createRoleChangeNotifier(String shardId) {
206         ActorRef shardRoleChangeNotifier = this.getContext().actorOf(
207             RoleChangeNotifier.getProps(shardId), shardId + "-notifier");
208         return Optional.<ActorRef>of(shardRoleChangeNotifier);
209     }
210
211     @Override
212     public void postStop() {
213         super.postStop();
214
215         if(txCommitTimeoutCheckSchedule != null) {
216             txCommitTimeoutCheckSchedule.cancel();
217         }
218     }
219
220     @Override
221     public void onReceiveRecover(final Object message) throws Exception {
222         if(LOG.isDebugEnabled()) {
223             LOG.debug("onReceiveRecover: Received message {} from {}",
224                 message.getClass().toString(),
225                 getSender());
226         }
227
228         if (message instanceof RecoveryFailure){
229             LOG.error(((RecoveryFailure) message).cause(), "Recovery failed because of this cause");
230
231             // Even though recovery failed, we still need to finish our recovery, eg send the
232             // ActorInitialized message and start the txCommitTimeoutCheckSchedule.
233             onRecoveryComplete();
234         } else {
235             super.onReceiveRecover(message);
236         }
237     }
238
239     @Override
240     public void onReceiveCommand(final Object message) throws Exception {
241         if(LOG.isDebugEnabled()) {
242             LOG.debug("onReceiveCommand: Received message {} from {}", message, getSender());
243         }
244
245         if(message.getClass().equals(ReadDataReply.SERIALIZABLE_CLASS)) {
246             handleReadDataReply(message);
247         } else if (message.getClass().equals(CreateTransaction.SERIALIZABLE_CLASS)) {
248             handleCreateTransaction(message);
249         } else if(message instanceof ForwardedReadyTransaction) {
250             handleForwardedReadyTransaction((ForwardedReadyTransaction)message);
251         } else if(message.getClass().equals(CanCommitTransaction.SERIALIZABLE_CLASS)) {
252             handleCanCommitTransaction(CanCommitTransaction.fromSerializable(message));
253         } else if(message.getClass().equals(CommitTransaction.SERIALIZABLE_CLASS)) {
254             handleCommitTransaction(CommitTransaction.fromSerializable(message));
255         } else if(message.getClass().equals(AbortTransaction.SERIALIZABLE_CLASS)) {
256             handleAbortTransaction(AbortTransaction.fromSerializable(message));
257         } else if (message.getClass().equals(CloseTransactionChain.SERIALIZABLE_CLASS)){
258             closeTransactionChain(CloseTransactionChain.fromSerializable(message));
259         } else if (message instanceof RegisterChangeListener) {
260             registerChangeListener((RegisterChangeListener) message);
261         } else if (message instanceof UpdateSchemaContext) {
262             updateSchemaContext((UpdateSchemaContext) message);
263         } else if (message instanceof PeerAddressResolved) {
264             PeerAddressResolved resolved = (PeerAddressResolved) message;
265             setPeerAddress(resolved.getPeerId().toString(),
266                 resolved.getPeerAddress());
267         } else if(message.equals(TX_COMMIT_TIMEOUT_CHECK_MESSAGE)) {
268             handleTransactionCommitTimeoutCheck();
269         } else {
270             super.onReceiveCommand(message);
271         }
272     }
273
274     @Override
275     protected Optional<ActorRef> getRoleChangeNotifier() {
276         return roleChangeNotifier;
277     }
278
279     private void handleTransactionCommitTimeoutCheck() {
280         CohortEntry cohortEntry = commitCoordinator.getCurrentCohortEntry();
281         if(cohortEntry != null) {
282             long elapsed = System.currentTimeMillis() - cohortEntry.getLastAccessTime();
283             if(elapsed > transactionCommitTimeout) {
284                 LOG.warning("Current transaction {} has timed out after {} ms - aborting",
285                         cohortEntry.getTransactionID(), transactionCommitTimeout);
286
287                 doAbortTransaction(cohortEntry.getTransactionID(), null);
288             }
289         }
290     }
291
292     private void handleCommitTransaction(final CommitTransaction commit) {
293         final String transactionID = commit.getTransactionID();
294
295         LOG.debug("Committing transaction {}", transactionID);
296
297         // Get the current in-progress cohort entry in the commitCoordinator if it corresponds to
298         // this transaction.
299         final CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
300         if(cohortEntry == null) {
301             // We're not the current Tx - the Tx was likely expired b/c it took too long in
302             // between the canCommit and commit messages.
303             IllegalStateException ex = new IllegalStateException(
304                     String.format("Cannot commit transaction %s - it is not the current transaction",
305                             transactionID));
306             LOG.error(ex.getMessage());
307             shardMBean.incrementFailedTransactionsCount();
308             getSender().tell(new akka.actor.Status.Failure(ex), getSelf());
309             return;
310         }
311
312         // We perform the preCommit phase here atomically with the commit phase. This is an
313         // optimization to eliminate the overhead of an extra preCommit message. We lose front-end
314         // coordination of preCommit across shards in case of failure but preCommit should not
315         // normally fail since we ensure only one concurrent 3-phase commit.
316
317         try {
318             // We block on the future here so we don't have to worry about possibly accessing our
319             // state on a different thread outside of our dispatcher. Also, the data store
320             // currently uses a same thread executor anyway.
321             cohortEntry.getCohort().preCommit().get();
322
323             // If we do not have any followers and we are not using persistence we can
324             // apply modification to the state immediately
325             if(!hasFollowers() && !persistence().isRecoveryApplicable()){
326                 applyModificationToState(getSender(), transactionID, cohortEntry.getModification());
327             } else {
328                 Shard.this.persistData(getSender(), transactionID,
329                         new CompositeModificationByteStringPayload(cohortEntry.getModification().toSerializable()));
330             }
331         } catch (InterruptedException | ExecutionException e) {
332             LOG.error(e, "An exception occurred while preCommitting transaction {}",
333                     cohortEntry.getTransactionID());
334             shardMBean.incrementFailedTransactionsCount();
335             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
336         }
337
338         cohortEntry.updateLastAccessTime();
339     }
340
341     private void finishCommit(@Nonnull final ActorRef sender, final @Nonnull String transactionID) {
342         // With persistence enabled, this method is called via applyState by the leader strategy
343         // after the commit has been replicated to a majority of the followers.
344
345         CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
346         if(cohortEntry == null) {
347             // The transaction is no longer the current commit. This can happen if the transaction
348             // was aborted prior, most likely due to timeout in the front-end. We need to finish
349             // committing the transaction though since it was successfully persisted and replicated
350             // however we can't use the original cohort b/c it was already preCommitted and may
351             // conflict with the current commit or may have been aborted so we commit with a new
352             // transaction.
353             cohortEntry = commitCoordinator.getAndRemoveCohortEntry(transactionID);
354             if(cohortEntry != null) {
355                 commitWithNewTransaction(cohortEntry.getModification());
356                 sender.tell(CommitTransactionReply.INSTANCE.toSerializable(), getSelf());
357             } else {
358                 // This really shouldn't happen - it likely means that persistence or replication
359                 // took so long to complete such that the cohort entry was expired from the cache.
360                 IllegalStateException ex = new IllegalStateException(
361                         String.format("Could not finish committing transaction %s - no CohortEntry found",
362                                 transactionID));
363                 LOG.error(ex.getMessage());
364                 sender.tell(new akka.actor.Status.Failure(ex), getSelf());
365             }
366
367             return;
368         }
369
370         LOG.debug("Finishing commit for transaction {}", cohortEntry.getTransactionID());
371
372         try {
373             // We block on the future here so we don't have to worry about possibly accessing our
374             // state on a different thread outside of our dispatcher. Also, the data store
375             // currently uses a same thread executor anyway.
376             cohortEntry.getCohort().commit().get();
377
378             sender.tell(CommitTransactionReply.INSTANCE.toSerializable(), getSelf());
379
380             shardMBean.incrementCommittedTransactionCount();
381             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
382
383         } catch (InterruptedException | ExecutionException e) {
384             sender.tell(new akka.actor.Status.Failure(e), getSelf());
385
386             LOG.error(e, "An exception occurred while committing transaction {}", transactionID);
387             shardMBean.incrementFailedTransactionsCount();
388         }
389
390         commitCoordinator.currentTransactionComplete(transactionID, true);
391     }
392
393     private void handleCanCommitTransaction(final CanCommitTransaction canCommit) {
394         LOG.debug("Can committing transaction {}", canCommit.getTransactionID());
395         commitCoordinator.handleCanCommit(canCommit, getSender(), self());
396     }
397
398     private void handleForwardedReadyTransaction(ForwardedReadyTransaction ready) {
399         LOG.debug("Readying transaction {}, client version {}", ready.getTransactionID(),
400                 ready.getTxnClientVersion());
401
402         // This message is forwarded by the ShardTransaction on ready. We cache the cohort in the
403         // commitCoordinator in preparation for the subsequent three phase commit initiated by
404         // the front-end.
405         commitCoordinator.transactionReady(ready.getTransactionID(), ready.getCohort(),
406                 ready.getModification());
407
408         // Return our actor path as we'll handle the three phase commit, except if the Tx client
409         // version < 1 (Helium-1 version). This means the Tx was initiated by a base Helium version
410         // node. In that case, the subsequent 3-phase commit messages won't contain the
411         // transactionId so to maintain backwards compatibility, we create a separate cohort actor
412         // to provide the compatible behavior.
413         ActorRef replyActorPath = self();
414         if(ready.getTxnClientVersion() < DataStoreVersions.HELIUM_1_VERSION) {
415             LOG.debug("Creating BackwardsCompatibleThreePhaseCommitCohort");
416             replyActorPath = getContext().actorOf(BackwardsCompatibleThreePhaseCommitCohort.props(
417                     ready.getTransactionID()));
418         }
419
420         ReadyTransactionReply readyTransactionReply = new ReadyTransactionReply(
421                 Serialization.serializedActorPath(replyActorPath));
422         getSender().tell(ready.isReturnSerialized() ? readyTransactionReply.toSerializable() :
423                 readyTransactionReply, getSelf());
424     }
425
426     private void handleAbortTransaction(final AbortTransaction abort) {
427         doAbortTransaction(abort.getTransactionID(), getSender());
428     }
429
430     void doAbortTransaction(final String transactionID, final ActorRef sender) {
431         final CohortEntry cohortEntry = commitCoordinator.getCohortEntryIfCurrent(transactionID);
432         if(cohortEntry != null) {
433             LOG.debug("Aborting transaction {}", transactionID);
434
435             // We don't remove the cached cohort entry here (ie pass false) in case the Tx was
436             // aborted during replication in which case we may still commit locally if replication
437             // succeeds.
438             commitCoordinator.currentTransactionComplete(transactionID, false);
439
440             final ListenableFuture<Void> future = cohortEntry.getCohort().abort();
441             final ActorRef self = getSelf();
442
443             Futures.addCallback(future, new FutureCallback<Void>() {
444                 @Override
445                 public void onSuccess(final Void v) {
446                     shardMBean.incrementAbortTransactionsCount();
447
448                     if(sender != null) {
449                         sender.tell(AbortTransactionReply.INSTANCE.toSerializable(), self);
450                     }
451                 }
452
453                 @Override
454                 public void onFailure(final Throwable t) {
455                     LOG.error(t, "An exception happened during abort");
456
457                     if(sender != null) {
458                         sender.tell(new akka.actor.Status.Failure(t), self);
459                     }
460                 }
461             });
462         }
463     }
464
465     private void handleCreateTransaction(final Object message) {
466         if (isLeader()) {
467             createTransaction(CreateTransaction.fromSerializable(message));
468         } else if (getLeader() != null) {
469             getLeader().forward(message, getContext());
470         } else {
471             getSender().tell(new akka.actor.Status.Failure(new NoShardLeaderException(
472                 "Could not find shard leader so transaction cannot be created. This typically happens" +
473                 " when the system is coming up or recovering and a leader is being elected. Try again" +
474                 " later.")), getSelf());
475         }
476     }
477
478     private void handleReadDataReply(final Object message) {
479         // This must be for install snapshot. Don't want to open this up and trigger
480         // deSerialization
481
482         self().tell(new CaptureSnapshotReply(ReadDataReply.fromSerializableAsByteString(message)),
483                 self());
484
485         createSnapshotTransaction = null;
486
487         // Send a PoisonPill instead of sending close transaction because we do not really need
488         // a response
489         getSender().tell(PoisonPill.getInstance(), self());
490     }
491
492     private void closeTransactionChain(final CloseTransactionChain closeTransactionChain) {
493         DOMStoreTransactionChain chain =
494             transactionChains.remove(closeTransactionChain.getTransactionChainId());
495
496         if(chain != null) {
497             chain.close();
498         }
499     }
500
501     private ActorRef createTypedTransactionActor(int transactionType,
502             ShardTransactionIdentifier transactionId, String transactionChainId,
503             short clientVersion ) {
504
505         DOMStoreTransactionFactory factory = store;
506
507         if(!transactionChainId.isEmpty()) {
508             factory = transactionChains.get(transactionChainId);
509             if(factory == null){
510                 DOMStoreTransactionChain transactionChain = store.createTransactionChain();
511                 transactionChains.put(transactionChainId, transactionChain);
512                 factory = transactionChain;
513             }
514         }
515
516         if(this.schemaContext == null) {
517             throw new IllegalStateException("SchemaContext is not set");
518         }
519
520         if (transactionType == TransactionProxy.TransactionType.READ_ONLY.ordinal()) {
521
522             shardMBean.incrementReadOnlyTransactionCount();
523
524             return getContext().actorOf(
525                 ShardTransaction.props(factory.newReadOnlyTransaction(), getSelf(),
526                         schemaContext,datastoreContext, shardMBean,
527                         transactionId.getRemoteTransactionId(), clientVersion),
528                         transactionId.toString());
529
530         } else if (transactionType == TransactionProxy.TransactionType.READ_WRITE.ordinal()) {
531
532             shardMBean.incrementReadWriteTransactionCount();
533
534             return getContext().actorOf(
535                 ShardTransaction.props(factory.newReadWriteTransaction(), getSelf(),
536                         schemaContext, datastoreContext, shardMBean,
537                         transactionId.getRemoteTransactionId(), clientVersion),
538                         transactionId.toString());
539
540
541         } else if (transactionType == TransactionProxy.TransactionType.WRITE_ONLY.ordinal()) {
542
543             shardMBean.incrementWriteOnlyTransactionCount();
544
545             return getContext().actorOf(
546                 ShardTransaction.props(factory.newWriteOnlyTransaction(), getSelf(),
547                         schemaContext, datastoreContext, shardMBean,
548                         transactionId.getRemoteTransactionId(), clientVersion),
549                         transactionId.toString());
550         } else {
551             throw new IllegalArgumentException(
552                 "Shard="+name + ":CreateTransaction message has unidentified transaction type="
553                     + transactionType);
554         }
555     }
556
557     private void createTransaction(CreateTransaction createTransaction) {
558         try {
559             ActorRef transactionActor = createTransaction(createTransaction.getTransactionType(),
560                 createTransaction.getTransactionId(), createTransaction.getTransactionChainId(),
561                 createTransaction.getVersion());
562
563             getSender().tell(new CreateTransactionReply(Serialization.serializedActorPath(transactionActor),
564                     createTransaction.getTransactionId()).toSerializable(), getSelf());
565         } catch (Exception e) {
566             getSender().tell(new akka.actor.Status.Failure(e), getSelf());
567         }
568     }
569
570     private ActorRef createTransaction(int transactionType, String remoteTransactionId,
571             String transactionChainId, short clientVersion) {
572
573         ShardTransactionIdentifier transactionId =
574             ShardTransactionIdentifier.builder()
575                 .remoteTransactionId(remoteTransactionId)
576                 .build();
577
578         if(LOG.isDebugEnabled()) {
579             LOG.debug("Creating transaction : {} ", transactionId);
580         }
581
582         ActorRef transactionActor = createTypedTransactionActor(transactionType, transactionId,
583                 transactionChainId, clientVersion);
584
585         return transactionActor;
586     }
587
588     private void syncCommitTransaction(final DOMStoreWriteTransaction transaction)
589         throws ExecutionException, InterruptedException {
590         DOMStoreThreePhaseCommitCohort commitCohort = transaction.ready();
591         commitCohort.preCommit().get();
592         commitCohort.commit().get();
593     }
594
595     private void commitWithNewTransaction(final Modification modification) {
596         DOMStoreWriteTransaction tx = store.newWriteOnlyTransaction();
597         modification.apply(tx);
598         try {
599             syncCommitTransaction(tx);
600             shardMBean.incrementCommittedTransactionCount();
601             shardMBean.setLastCommittedTransactionTime(System.currentTimeMillis());
602         } catch (InterruptedException | ExecutionException e) {
603             shardMBean.incrementFailedTransactionsCount();
604             LOG.error(e, "Failed to commit");
605         }
606     }
607
608     private void updateSchemaContext(final UpdateSchemaContext message) {
609         this.schemaContext = message.getSchemaContext();
610         updateSchemaContext(message.getSchemaContext());
611         store.onGlobalContextUpdated(message.getSchemaContext());
612     }
613
614     @VisibleForTesting
615     void updateSchemaContext(final SchemaContext schemaContext) {
616         store.onGlobalContextUpdated(schemaContext);
617     }
618
619     private void registerChangeListener(final RegisterChangeListener registerChangeListener) {
620
621         LOG.debug("registerDataChangeListener for {}", registerChangeListener.getPath());
622
623         ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
624                                                      NormalizedNode<?, ?>>> registration;
625         if(isLeader()) {
626             registration = doChangeListenerRegistration(registerChangeListener);
627         } else {
628             LOG.debug("Shard is not the leader - delaying registration");
629
630             DelayedListenerRegistration delayedReg =
631                     new DelayedListenerRegistration(registerChangeListener);
632             delayedListenerRegistrations.add(delayedReg);
633             registration = delayedReg;
634         }
635
636         ActorRef listenerRegistration = getContext().actorOf(
637                 DataChangeListenerRegistration.props(registration));
638
639         LOG.debug("registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
640                     listenerRegistration.path());
641
642         getSender().tell(new RegisterChangeListenerReply(listenerRegistration.path()), getSelf());
643     }
644
645     private ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
646                                                NormalizedNode<?, ?>>> doChangeListenerRegistration(
647             final RegisterChangeListener registerChangeListener) {
648
649         ActorSelection dataChangeListenerPath = getContext().system().actorSelection(
650                 registerChangeListener.getDataChangeListenerPath());
651
652         // Notify the listener if notifications should be enabled or not
653         // If this shard is the leader then it will enable notifications else
654         // it will not
655         dataChangeListenerPath.tell(new EnableNotification(true), getSelf());
656
657         // Now store a reference to the data change listener so it can be notified
658         // at a later point if notifications should be enabled or disabled
659         dataChangeListeners.add(dataChangeListenerPath);
660
661         AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> listener =
662                 new DataChangeListenerProxy(dataChangeListenerPath);
663
664         LOG.debug("Registering for path {}", registerChangeListener.getPath());
665
666         return store.registerChangeListener(registerChangeListener.getPath(), listener,
667                 registerChangeListener.getScope());
668     }
669
670     private boolean isMetricsCaptureEnabled(){
671         CommonConfig config = new CommonConfig(getContext().system().settings().config());
672         return config.isMetricCaptureEnabled();
673     }
674
675     @Override
676     protected
677     void startLogRecoveryBatch(final int maxBatchSize) {
678         currentLogRecoveryBatch = Lists.newArrayListWithCapacity(maxBatchSize);
679
680         if(LOG.isDebugEnabled()) {
681             LOG.debug("{} : starting log recovery batch with max size {}", persistenceId(), maxBatchSize);
682         }
683     }
684
685     @Override
686     protected void appendRecoveredLogEntry(final Payload data) {
687         if (data instanceof CompositeModificationPayload) {
688             currentLogRecoveryBatch.add(((CompositeModificationPayload) data).getModification());
689         } else if (data instanceof CompositeModificationByteStringPayload) {
690             currentLogRecoveryBatch.add(((CompositeModificationByteStringPayload) data).getModification());
691         } else {
692             LOG.error("Unknown state received {} during recovery", data);
693         }
694     }
695
696     @Override
697     protected void applyRecoverySnapshot(final ByteString snapshot) {
698         if(recoveryCoordinator == null) {
699             recoveryCoordinator = new ShardRecoveryCoordinator(persistenceId(), schemaContext);
700         }
701
702         recoveryCoordinator.submit(snapshot, store.newWriteOnlyTransaction());
703
704         if(LOG.isDebugEnabled()) {
705             LOG.debug("{} : submitted recovery sbapshot", persistenceId());
706         }
707     }
708
709     @Override
710     protected void applyCurrentLogRecoveryBatch() {
711         if(recoveryCoordinator == null) {
712             recoveryCoordinator = new ShardRecoveryCoordinator(persistenceId(), schemaContext);
713         }
714
715         recoveryCoordinator.submit(currentLogRecoveryBatch, store.newWriteOnlyTransaction());
716
717         if(LOG.isDebugEnabled()) {
718             LOG.debug("{} : submitted log recovery batch with size {}", persistenceId(),
719                     currentLogRecoveryBatch.size());
720         }
721     }
722
723     @Override
724     protected void onRecoveryComplete() {
725         if(recoveryCoordinator != null) {
726             Collection<DOMStoreWriteTransaction> txList = recoveryCoordinator.getTransactions();
727
728             if(LOG.isDebugEnabled()) {
729                 LOG.debug("{} : recovery complete - committing {} Tx's", persistenceId(), txList.size());
730             }
731
732             for(DOMStoreWriteTransaction tx: txList) {
733                 try {
734                     syncCommitTransaction(tx);
735                     shardMBean.incrementCommittedTransactionCount();
736                 } catch (InterruptedException | ExecutionException e) {
737                     shardMBean.incrementFailedTransactionsCount();
738                     LOG.error(e, "Failed to commit");
739                 }
740             }
741         }
742
743         recoveryCoordinator = null;
744         currentLogRecoveryBatch = null;
745         updateJournalStats();
746
747         //notify shard manager
748         getContext().parent().tell(new ActorInitialized(), getSelf());
749
750         // Being paranoid here - this method should only be called once but just in case...
751         if(txCommitTimeoutCheckSchedule == null) {
752             // Schedule a message to be periodically sent to check if the current in-progress
753             // transaction should be expired and aborted.
754             FiniteDuration period = Duration.create(transactionCommitTimeout / 3, TimeUnit.MILLISECONDS);
755             txCommitTimeoutCheckSchedule = getContext().system().scheduler().schedule(
756                     period, period, getSelf(),
757                     TX_COMMIT_TIMEOUT_CHECK_MESSAGE, getContext().dispatcher(), ActorRef.noSender());
758         }
759     }
760
761     @Override
762     protected void applyState(final ActorRef clientActor, final String identifier, final Object data) {
763
764         if (data instanceof CompositeModificationPayload) {
765             Object modification = ((CompositeModificationPayload) data).getModification();
766
767             applyModificationToState(clientActor, identifier, modification);
768         } else if(data instanceof CompositeModificationByteStringPayload ){
769             Object modification = ((CompositeModificationByteStringPayload) data).getModification();
770
771             applyModificationToState(clientActor, identifier, modification);
772
773         } else {
774             LOG.error("Unknown state received {} Class loader = {} CompositeNodeMod.ClassLoader = {}",
775                     data, data.getClass().getClassLoader(),
776                     CompositeModificationPayload.class.getClassLoader());
777         }
778
779         updateJournalStats();
780
781     }
782
783     private void applyModificationToState(ActorRef clientActor, String identifier, Object modification) {
784         if(modification == null) {
785             LOG.error(
786                     "modification is null - this is very unexpected, clientActor = {}, identifier = {}",
787                     identifier, clientActor != null ? clientActor.path().toString() : null);
788         } else if(clientActor == null) {
789             // There's no clientActor to which to send a commit reply so we must be applying
790             // replicated state from the leader.
791             commitWithNewTransaction(MutableCompositeModification.fromSerializable(
792                     modification, schemaContext));
793         } else {
794             // This must be the OK to commit after replication consensus.
795             finishCommit(clientActor, identifier);
796         }
797     }
798
799     private void updateJournalStats() {
800         ReplicatedLogEntry lastLogEntry = getLastLogEntry();
801
802         if (lastLogEntry != null) {
803             shardMBean.setLastLogIndex(lastLogEntry.getIndex());
804             shardMBean.setLastLogTerm(lastLogEntry.getTerm());
805         }
806
807         shardMBean.setCommitIndex(getCommitIndex());
808         shardMBean.setLastApplied(getLastApplied());
809         shardMBean.setInMemoryJournalDataSize(getRaftActorContext().getReplicatedLog().dataSize());
810     }
811
812     @Override
813     protected void createSnapshot() {
814         if (createSnapshotTransaction == null) {
815
816             // Create a transaction. We are really going to treat the transaction as a worker
817             // so that this actor does not get block building the snapshot
818             createSnapshotTransaction = createTransaction(
819                 TransactionProxy.TransactionType.READ_ONLY.ordinal(),
820                 "createSnapshot" + ++createSnapshotTransactionCounter, "",
821                 DataStoreVersions.CURRENT_VERSION);
822
823             createSnapshotTransaction.tell(
824                 new ReadData(YangInstanceIdentifier.builder().build()).toSerializable(), self());
825
826         }
827     }
828
829     @VisibleForTesting
830     @Override
831     protected void applySnapshot(final ByteString snapshot) {
832         // Since this will be done only on Recovery or when this actor is a Follower
833         // we can safely commit everything in here. We not need to worry about event notifications
834         // as they would have already been disabled on the follower
835
836         LOG.info("Applying snapshot");
837         try {
838             DOMStoreWriteTransaction transaction = store.newWriteOnlyTransaction();
839             NormalizedNodeMessages.Node serializedNode = NormalizedNodeMessages.Node.parseFrom(snapshot);
840             NormalizedNode<?, ?> node = new NormalizedNodeToNodeCodec(schemaContext)
841                 .decode(serializedNode);
842
843             // delete everything first
844             transaction.delete(YangInstanceIdentifier.builder().build());
845
846             // Add everything from the remote node back
847             transaction.write(YangInstanceIdentifier.builder().build(), node);
848             syncCommitTransaction(transaction);
849         } catch (InvalidProtocolBufferException | InterruptedException | ExecutionException e) {
850             LOG.error(e, "An exception occurred when applying snapshot");
851         } finally {
852             LOG.info("Done applying snapshot");
853         }
854     }
855
856     @Override
857     protected void onStateChanged() {
858         boolean isLeader = isLeader();
859         for (ActorSelection dataChangeListener : dataChangeListeners) {
860             dataChangeListener.tell(new EnableNotification(isLeader), getSelf());
861         }
862
863         if(isLeader) {
864             for(DelayedListenerRegistration reg: delayedListenerRegistrations) {
865                 if(!reg.isClosed()) {
866                     reg.setDelegate(doChangeListenerRegistration(reg.getRegisterChangeListener()));
867                 }
868             }
869
870             delayedListenerRegistrations.clear();
871         }
872
873         shardMBean.setRaftState(getRaftState().name());
874         shardMBean.setCurrentTerm(getCurrentTerm());
875
876         // If this actor is no longer the leader close all the transaction chains
877         if(!isLeader){
878             for(Map.Entry<String, DOMStoreTransactionChain> entry : transactionChains.entrySet()){
879                 if(LOG.isDebugEnabled()) {
880                     LOG.debug(
881                         "onStateChanged: Closing transaction chain {} because shard {} is no longer the leader",
882                         entry.getKey(), getId());
883                 }
884                 entry.getValue().close();
885             }
886
887             transactionChains.clear();
888         }
889     }
890
891     @Override
892     protected DataPersistenceProvider persistence() {
893         return dataPersistenceProvider;
894     }
895
896     @Override protected void onLeaderChanged(final String oldLeader, final String newLeader) {
897         shardMBean.setLeader(newLeader);
898     }
899
900     @Override public String persistenceId() {
901         return this.name.toString();
902     }
903
904     @VisibleForTesting
905     DataPersistenceProvider getDataPersistenceProvider() {
906         return dataPersistenceProvider;
907     }
908
909     private static class ShardCreator implements Creator<Shard> {
910
911         private static final long serialVersionUID = 1L;
912
913         final ShardIdentifier name;
914         final Map<ShardIdentifier, String> peerAddresses;
915         final DatastoreContext datastoreContext;
916         final SchemaContext schemaContext;
917
918         ShardCreator(final ShardIdentifier name, final Map<ShardIdentifier, String> peerAddresses,
919                 final DatastoreContext datastoreContext, final SchemaContext schemaContext) {
920             this.name = name;
921             this.peerAddresses = peerAddresses;
922             this.datastoreContext = datastoreContext;
923             this.schemaContext = schemaContext;
924         }
925
926         @Override
927         public Shard create() throws Exception {
928             return new Shard(name, peerAddresses, datastoreContext, schemaContext);
929         }
930     }
931
932     @VisibleForTesting
933     InMemoryDOMDataStore getDataStore() {
934         return store;
935     }
936
937     @VisibleForTesting
938     ShardStats getShardMBean() {
939         return shardMBean;
940     }
941
942     private static class DelayedListenerRegistration implements
943         ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>> {
944
945         private volatile boolean closed;
946
947         private final RegisterChangeListener registerChangeListener;
948
949         private volatile ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
950                                                              NormalizedNode<?, ?>>> delegate;
951
952         DelayedListenerRegistration(final RegisterChangeListener registerChangeListener) {
953             this.registerChangeListener = registerChangeListener;
954         }
955
956         void setDelegate( final ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
957                                             NormalizedNode<?, ?>>> registration) {
958             this.delegate = registration;
959         }
960
961         boolean isClosed() {
962             return closed;
963         }
964
965         RegisterChangeListener getRegisterChangeListener() {
966             return registerChangeListener;
967         }
968
969         @Override
970         public AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> getInstance() {
971             return delegate != null ? delegate.getInstance() : null;
972         }
973
974         @Override
975         public void close() {
976             closed = true;
977             if(delegate != null) {
978                 delegate.close();
979             }
980         }
981     }
982 }