/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.controller.cluster.datastore;
import akka.actor.ActorPath;
import akka.actor.ActorSelection;
import akka.dispatch.OnComplete;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.FinalizablePhantomReference;
import com.google.common.base.FinalizableReferenceQueue;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.util.concurrent.CheckedFuture;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.SettableFuture;
import org.opendaylight.controller.cluster.datastore.identifiers.TransactionIdentifier;
import org.opendaylight.controller.cluster.datastore.messages.CloseTransaction;
import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
import org.opendaylight.controller.cluster.datastore.messages.DataExists;
import org.opendaylight.controller.cluster.datastore.messages.DataExistsReply;
import org.opendaylight.controller.cluster.datastore.messages.DeleteData;
import org.opendaylight.controller.cluster.datastore.messages.MergeData;
import org.opendaylight.controller.cluster.datastore.messages.ReadData;
import org.opendaylight.controller.cluster.datastore.messages.ReadDataReply;
import org.opendaylight.controller.cluster.datastore.messages.ReadyTransaction;
import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
import org.opendaylight.controller.cluster.datastore.messages.WriteData;
import org.opendaylight.controller.cluster.datastore.shardstrategy.ShardStrategyFactory;
import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadWriteTransaction;
import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
import org.opendaylight.yangtools.util.concurrent.MappingCheckedFuture;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.model.api.SchemaContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import scala.Function1;
import scala.concurrent.Future;
import scala.runtime.AbstractFunction1;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
/**
* TransactionProxy acts as a proxy for one or more transactions that were created on a remote shard
*
* Creating a transaction on the consumer side will create one instance of a transaction proxy. If during
* the transaction reads and writes are done on data that belongs to different shards then a separate transaction will
* be created on each of those shards by the TransactionProxy
*
*
* The TransactionProxy does not make any guarantees about atomicity or order in which the transactions on the various
* shards will be executed.
*
*/
public class TransactionProxy implements DOMStoreReadWriteTransaction {
private final TransactionChainProxy transactionChainProxy;
public enum TransactionType {
READ_ONLY,
WRITE_ONLY,
READ_WRITE
}
static Function1 SAME_FAILURE_TRANSFORMER = new AbstractFunction1<
Throwable, Throwable>() {
@Override
public Throwable apply(Throwable failure) {
return failure;
}
};
private static final AtomicLong counter = new AtomicLong();
private static final Logger
LOG = LoggerFactory.getLogger(TransactionProxy.class);
/**
* Used to enqueue the PhantomReferences for read-only TransactionProxy instances. The
* FinalizableReferenceQueue is safe to use statically in an OSGi environment as it uses some
* trickery to clean up its internal thread when the bundle is unloaded.
*/
private static final FinalizableReferenceQueue phantomReferenceQueue =
new FinalizableReferenceQueue();
/**
* This stores the TransactionProxyCleanupPhantomReference instances statically, This is
* necessary because PhantomReferences need a hard reference so they're not garbage collected.
* Once finalized, the TransactionProxyCleanupPhantomReference removes itself from this map
* and thus becomes eligible for garbage collection.
*/
private static final Map phantomReferenceCache =
new ConcurrentHashMap<>();
/**
* A PhantomReference that closes remote transactions for a TransactionProxy when it's
* garbage collected. This is used for read-only transactions as they're not explicitly closed
* by clients. So the only way to detect that a transaction is no longer in use and it's safe
* to clean up is when it's garbage collected. It's inexact as to when an instance will be GC'ed
* but TransactionProxy instances should generally be short-lived enough to avoid being moved
* to the old generation space and thus should be cleaned up in a timely manner as the GC
* runs on the young generation (eden, swap1...) space much more frequently.
*/
private static class TransactionProxyCleanupPhantomReference
extends FinalizablePhantomReference {
private final List remoteTransactionActors;
private final AtomicBoolean remoteTransactionActorsMB;
private final ActorContext actorContext;
private final TransactionIdentifier identifier;
protected TransactionProxyCleanupPhantomReference(TransactionProxy referent) {
super(referent, phantomReferenceQueue);
// Note we need to cache the relevant fields from the TransactionProxy as we can't
// have a hard reference to the TransactionProxy instance itself.
remoteTransactionActors = referent.remoteTransactionActors;
remoteTransactionActorsMB = referent.remoteTransactionActorsMB;
actorContext = referent.actorContext;
identifier = referent.identifier;
}
@Override
public void finalizeReferent() {
LOG.trace("Cleaning up {} Tx actors for TransactionProxy {}",
remoteTransactionActors.size(), identifier);
phantomReferenceCache.remove(this);
// Access the memory barrier volatile to ensure all previous updates to the
// remoteTransactionActors list are visible to this thread.
if(remoteTransactionActorsMB.get()) {
for(ActorSelection actor : remoteTransactionActors) {
LOG.trace("Sending CloseTransaction to {}", actor);
actorContext.sendRemoteOperationAsync(actor,
new CloseTransaction().toSerializable());
}
}
}
}
/**
* Stores the remote Tx actors for each requested data store path to be used by the
* PhantomReference to close the remote Tx's. This is only used for read-only Tx's. The
* remoteTransactionActorsMB volatile serves as a memory barrier to publish updates to the
* remoteTransactionActors list so they will be visible to the thread accessing the
* PhantomReference.
*/
private List remoteTransactionActors;
private AtomicBoolean remoteTransactionActorsMB;
private final Map remoteTransactionPaths = new HashMap<>();
private final TransactionType transactionType;
private final ActorContext actorContext;
private final TransactionIdentifier identifier;
private final SchemaContext schemaContext;
private boolean inReadyState;
public TransactionProxy(ActorContext actorContext, TransactionType transactionType) {
this(actorContext, transactionType, null);
}
@VisibleForTesting
List> getRecordedOperationFutures() {
List> recordedOperationFutures = Lists.newArrayList();
for(TransactionContext transactionContext : remoteTransactionPaths.values()) {
recordedOperationFutures.addAll(transactionContext.getRecordedOperationFutures());
}
return recordedOperationFutures;
}
public TransactionProxy(ActorContext actorContext, TransactionType transactionType, TransactionChainProxy transactionChainProxy) {
this.actorContext = Preconditions.checkNotNull(actorContext,
"actorContext should not be null");
this.transactionType = Preconditions.checkNotNull(transactionType,
"transactionType should not be null");
this.schemaContext = Preconditions.checkNotNull(actorContext.getSchemaContext(),
"schemaContext should not be null");
this.transactionChainProxy = transactionChainProxy;
String memberName = actorContext.getCurrentMemberName();
if(memberName == null){
memberName = "UNKNOWN-MEMBER";
}
this.identifier = TransactionIdentifier.builder().memberName(memberName).counter(
counter.getAndIncrement()).build();
if(transactionType == TransactionType.READ_ONLY) {
// Read-only Tx's aren't explicitly closed by the client so we create a PhantomReference
// to close the remote Tx's when this instance is no longer in use and is garbage
// collected.
remoteTransactionActors = Lists.newArrayList();
remoteTransactionActorsMB = new AtomicBoolean();
TransactionProxyCleanupPhantomReference cleanup =
new TransactionProxyCleanupPhantomReference(this);
phantomReferenceCache.put(cleanup, cleanup);
}
LOG.debug("Created txn {} of type {}", identifier, transactionType);
}
@Override
public CheckedFuture>, ReadFailedException> read(
final YangInstanceIdentifier path) {
Preconditions.checkState(transactionType != TransactionType.WRITE_ONLY,
"Read operation on write-only transaction is not allowed");
LOG.debug("Tx {} read {}", identifier, path);
createTransactionIfMissing(actorContext, path);
return transactionContext(path).readData(path);
}
@Override
public CheckedFuture exists(YangInstanceIdentifier path) {
Preconditions.checkState(transactionType != TransactionType.WRITE_ONLY,
"Exists operation on write-only transaction is not allowed");
LOG.debug("Tx {} exists {}", identifier, path);
createTransactionIfMissing(actorContext, path);
return transactionContext(path).dataExists(path);
}
private void checkModificationState() {
Preconditions.checkState(transactionType != TransactionType.READ_ONLY,
"Modification operation on read-only transaction is not allowed");
Preconditions.checkState(!inReadyState,
"Transaction is sealed - further modifications are not allowed");
}
@Override
public void write(YangInstanceIdentifier path, NormalizedNode, ?> data) {
checkModificationState();
LOG.debug("Tx {} write {}", identifier, path);
createTransactionIfMissing(actorContext, path);
transactionContext(path).writeData(path, data);
}
@Override
public void merge(YangInstanceIdentifier path, NormalizedNode, ?> data) {
checkModificationState();
LOG.debug("Tx {} merge {}", identifier, path);
createTransactionIfMissing(actorContext, path);
transactionContext(path).mergeData(path, data);
}
@Override
public void delete(YangInstanceIdentifier path) {
checkModificationState();
LOG.debug("Tx {} delete {}", identifier, path);
createTransactionIfMissing(actorContext, path);
transactionContext(path).deleteData(path);
}
@Override
public DOMStoreThreePhaseCommitCohort ready() {
checkModificationState();
inReadyState = true;
LOG.debug("Tx {} Trying to get {} transactions ready for commit", identifier,
remoteTransactionPaths.size());
List> cohortPathFutures = Lists.newArrayList();
for(TransactionContext transactionContext : remoteTransactionPaths.values()) {
LOG.debug("Tx {} Readying transaction for shard {}", identifier,
transactionContext.getShardName());
cohortPathFutures.add(transactionContext.readyTransaction());
}
if(transactionChainProxy != null){
transactionChainProxy.onTransactionReady(cohortPathFutures);
}
return new ThreePhaseCommitCohortProxy(actorContext, cohortPathFutures,
identifier.toString());
}
@Override
public Object getIdentifier() {
return this.identifier;
}
@Override
public void close() {
for(TransactionContext transactionContext : remoteTransactionPaths.values()) {
transactionContext.closeTransaction();
}
remoteTransactionPaths.clear();
if(transactionType == TransactionType.READ_ONLY) {
remoteTransactionActors.clear();
remoteTransactionActorsMB.set(true);
}
}
private TransactionContext transactionContext(YangInstanceIdentifier path){
String shardName = shardNameFromIdentifier(path);
return remoteTransactionPaths.get(shardName);
}
private String shardNameFromIdentifier(YangInstanceIdentifier path){
return ShardStrategyFactory.getStrategy(path).findShard(path);
}
private void createTransactionIfMissing(ActorContext actorContext,
YangInstanceIdentifier path) {
if(transactionChainProxy != null){
transactionChainProxy.waitTillCurrentTransactionReady();
}
String shardName = ShardStrategyFactory.getStrategy(path).findShard(path);
TransactionContext transactionContext =
remoteTransactionPaths.get(shardName);
if (transactionContext != null) {
// A transaction already exists with that shard
return;
}
try {
Object response = actorContext.executeShardOperation(shardName,
new CreateTransaction(identifier.toString(), this.transactionType.ordinal(),
getTransactionChainId()).toSerializable());
if (response.getClass().equals(CreateTransactionReply.SERIALIZABLE_CLASS)) {
CreateTransactionReply reply =
CreateTransactionReply.fromSerializable(response);
String transactionPath = reply.getTransactionPath();
LOG.debug("Tx {} Received transaction path = {}", identifier, transactionPath);
ActorSelection transactionActor = actorContext.actorSelection(transactionPath);
if (transactionType == TransactionType.READ_ONLY) {
// Add the actor to the remoteTransactionActors list for access by the
// cleanup PhantonReference.
remoteTransactionActors.add(transactionActor);
// Write to the memory barrier volatile to publish the above update to the
// remoteTransactionActors list for thread visibility.
remoteTransactionActorsMB.set(true);
}
transactionContext = new TransactionContextImpl(shardName, transactionPath,
transactionActor, identifier, actorContext, schemaContext);
remoteTransactionPaths.put(shardName, transactionContext);
} else {
throw new IllegalArgumentException(String.format(
"Invalid reply type {} for CreateTransaction", response.getClass()));
}
} catch (Exception e) {
LOG.debug("Tx {} Creating NoOpTransaction because of : {}", identifier, e.getMessage());
remoteTransactionPaths
.put(shardName, new NoOpTransactionContext(shardName, e, identifier));
}
}
public String getTransactionChainId() {
if(transactionChainProxy == null){
return "";
}
return transactionChainProxy.getTransactionChainId();
}
private interface TransactionContext {
String getShardName();
void closeTransaction();
Future readyTransaction();
void writeData(YangInstanceIdentifier path, NormalizedNode, ?> data);
void deleteData(YangInstanceIdentifier path);
void mergeData(YangInstanceIdentifier path, NormalizedNode, ?> data);
CheckedFuture>, ReadFailedException> readData(
final YangInstanceIdentifier path);
CheckedFuture dataExists(YangInstanceIdentifier path);
List> getRecordedOperationFutures();
}
private static abstract class AbstractTransactionContext implements TransactionContext {
protected final TransactionIdentifier identifier;
protected final String shardName;
protected final List> recordedOperationFutures = Lists.newArrayList();
AbstractTransactionContext(String shardName, TransactionIdentifier identifier) {
this.shardName = shardName;
this.identifier = identifier;
}
@Override
public String getShardName() {
return shardName;
}
@Override
public List> getRecordedOperationFutures() {
return recordedOperationFutures;
}
}
private static class TransactionContextImpl extends AbstractTransactionContext {
private final Logger LOG = LoggerFactory.getLogger(TransactionContextImpl.class);
private final ActorContext actorContext;
private final SchemaContext schemaContext;
private final String actorPath;
private final ActorSelection actor;
private TransactionContextImpl(String shardName, String actorPath,
ActorSelection actor, TransactionIdentifier identifier, ActorContext actorContext,
SchemaContext schemaContext) {
super(shardName, identifier);
this.actorPath = actorPath;
this.actor = actor;
this.actorContext = actorContext;
this.schemaContext = schemaContext;
}
private ActorSelection getActor() {
return actor;
}
private String getResolvedCohortPath(String cohortPath) {
return actorContext.resolvePath(actorPath, cohortPath);
}
@Override
public void closeTransaction() {
LOG.debug("Tx {} closeTransaction called", identifier);
actorContext.sendRemoteOperationAsync(getActor(), new CloseTransaction().toSerializable());
}
@Override
public Future readyTransaction() {
LOG.debug("Tx {} readyTransaction called with {} previous recorded operations pending",
identifier, recordedOperationFutures.size());
// Send the ReadyTransaction message to the Tx actor.
final Future