opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/RemoteTransactionContextSupport.java

   1 /*
   2  * Copyright (c) 2015 Brocade Communications Systems, Inc. and others.  All rights reserved.
   3  * Copyright (c) 2015 Cisco Systems, Inc. and others.  All rights reserved.
   4  *
   5  * This program and the accompanying materials are made available under the
   6  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   7  * and is available at http://www.eclipse.org/legal/epl-v10.html
   8  */
   9 package org.opendaylight.controller.cluster.datastore;
  10
  11 import akka.actor.ActorSelection;
  12 import akka.dispatch.OnComplete;
  13 import com.google.common.base.Preconditions;
  14 import java.util.concurrent.TimeUnit;
  15 import org.opendaylight.controller.cluster.datastore.compat.PreLithiumTransactionContextImpl;
  16 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
  17 import org.opendaylight.controller.cluster.datastore.identifiers.TransactionIdentifier;
  18 import org.opendaylight.controller.cluster.datastore.messages.CreateTransaction;
  19 import org.opendaylight.controller.cluster.datastore.messages.CreateTransactionReply;
  20 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  21 import org.slf4j.Logger;
  22 import org.slf4j.LoggerFactory;
  23 import scala.concurrent.Future;
  24 import scala.concurrent.duration.FiniteDuration;
  25
  26 /**
  27  * Handles creation of TransactionContext instances for remote transactions. This class creates
  28  * remote transactions, if necessary, by sending CreateTransaction messages with retries, up to a limit,
  29  * if the shard doesn't have a leader yet. This is done by scheduling a retry task after a short delay.
  30  * <p>
  31  * The end result from a completed CreateTransaction message is a TransactionContext that is
  32  * used to perform transaction operations. Transaction operations that occur before the
  33  * CreateTransaction completes are cache via a TransactionContextWrapper and executed once the
  34  * CreateTransaction completes, successfully or not.
  35  */
  36 final class RemoteTransactionContextSupport {
  37     private static final Logger LOG = LoggerFactory.getLogger(RemoteTransactionContextSupport.class);
  38
  39     /**
  40      * Time interval in between transaction create retries.
  41      */
  42     private static final FiniteDuration CREATE_TX_TRY_INTERVAL = FiniteDuration.create(1, TimeUnit.SECONDS);
  43
  44     private final TransactionProxy parent;
  45     private final String shardName;
  46
  47     /**
  48      * The target primary shard.
  49      */
  50     private volatile ActorSelection primaryShard;
  51     private volatile int createTxTries;
  52
  53     private final TransactionContextWrapper transactionContextAdapter;
  54
  55     RemoteTransactionContextSupport(final TransactionContextWrapper transactionContextAdapter, final TransactionProxy parent,
  56             final String shardName) {
  57         this.parent = Preconditions.checkNotNull(parent);
  58         this.shardName = shardName;
  59         this.transactionContextAdapter = transactionContextAdapter;
  60         createTxTries = (int) (parent.getActorContext().getDatastoreContext().
  61                 getShardLeaderElectionTimeout().duration().toMillis() /
  62                 CREATE_TX_TRY_INTERVAL.toMillis());
  63     }
  64
  65     String getShardName() {
  66         return shardName;
  67     }
  68
  69     private TransactionType getTransactionType() {
  70         return parent.getType();
  71     }
  72
  73     private ActorContext getActorContext() {
  74         return parent.getActorContext();
  75     }
  76
  77     private OperationLimiter getOperationLimiter() {
  78         return transactionContextAdapter.getLimiter();
  79     }
  80
  81     private TransactionIdentifier getIdentifier() {
  82         return parent.getIdentifier();
  83     }
  84
  85     /**
  86      * Sets the target primary shard and initiates a CreateTransaction try.
  87      */
  88     void setPrimaryShard(ActorSelection primaryShard, short primaryVersion) {
  89         this.primaryShard = primaryShard;
  90
  91         if (getTransactionType() == TransactionType.WRITE_ONLY && primaryVersion >= DataStoreVersions.LITHIUM_VERSION &&
  92                 getActorContext().getDatastoreContext().isWriteOnlyTransactionOptimizationsEnabled()) {
  93             LOG.debug("Tx {} Primary shard {} found - creating WRITE_ONLY transaction context",
  94                 getIdentifier(), primaryShard);
  95
  96             // For write-only Tx's we prepare the transaction modifications directly on the shard actor
  97             // to avoid the overhead of creating a separate transaction actor.
  98             transactionContextAdapter.executePriorTransactionOperations(createValidTransactionContext(this.primaryShard,
  99                     this.primaryShard.path().toString(), primaryVersion));
 100         } else {
 101             tryCreateTransaction();
 102         }
 103     }
 104
 105     /**
 106      * Performs a CreateTransaction try async.
 107      */
 108     private void tryCreateTransaction() {
 109         if(LOG.isDebugEnabled()) {
 110             LOG.debug("Tx {} Primary shard {} found - trying create transaction", getIdentifier(), primaryShard);
 111         }
 112
 113         Object serializedCreateMessage = new CreateTransaction(getIdentifier().toString(),
 114             getTransactionType().ordinal(), getIdentifier().getChainId()).toSerializable();
 115
 116         Future<Object> createTxFuture = getActorContext().executeOperationAsync(primaryShard, serializedCreateMessage);
 117
 118         createTxFuture.onComplete(new OnComplete<Object>() {
 119             @Override
 120             public void onComplete(Throwable failure, Object response) {
 121                 onCreateTransactionComplete(failure, response);
 122             }
 123         }, getActorContext().getClientDispatcher());
 124     }
 125
 126     private void onCreateTransactionComplete(Throwable failure, Object response) {
 127         if(failure instanceof NoShardLeaderException) {
 128             // There's no leader for the shard yet - schedule and try again, unless we're out
 129             // of retries. Note: createTxTries is volatile as it may be written by different
 130             // threads however not concurrently, therefore decrementing it non-atomically here
 131             // is ok.
 132             if(--createTxTries > 0) {
 133                 LOG.debug("Tx {} Shard {} has no leader yet - scheduling create Tx retry",
 134                     getIdentifier(), shardName);
 135
 136                 getActorContext().getActorSystem().scheduler().scheduleOnce(CREATE_TX_TRY_INTERVAL,
 137                         new Runnable() {
 138                             @Override
 139                             public void run() {
 140                                 tryCreateTransaction();
 141                             }
 142                         }, getActorContext().getClientDispatcher());
 143                 return;
 144             }
 145         }
 146
 147         createTransactionContext(failure, response);
 148     }
 149
 150     private void createTransactionContext(Throwable failure, Object response) {
 151         // Create the TransactionContext from the response or failure. Store the new
 152         // TransactionContext locally until we've completed invoking the
 153         // TransactionOperations. This avoids thread timing issues which could cause
 154         // out-of-order TransactionOperations. Eg, on a modification operation, if the
 155         // TransactionContext is non-null, then we directly call the TransactionContext.
 156         // However, at the same time, the code may be executing the cached
 157         // TransactionOperations. So to avoid thus timing, we don't publish the
 158         // TransactionContext until after we've executed all cached TransactionOperations.
 159         TransactionContext localTransactionContext;
 160         if(failure != null) {
 161             LOG.debug("Tx {} Creating NoOpTransaction because of error", getIdentifier(), failure);
 162
 163             localTransactionContext = new NoOpTransactionContext(failure, getIdentifier());
 164         } else if (CreateTransactionReply.SERIALIZABLE_CLASS.equals(response.getClass())) {
 165             localTransactionContext = createValidTransactionContext(
 166                     CreateTransactionReply.fromSerializable(response));
 167         } else {
 168             IllegalArgumentException exception = new IllegalArgumentException(String.format(
 169                     "Invalid reply type %s for CreateTransaction", response.getClass()));
 170
 171             localTransactionContext = new NoOpTransactionContext(exception, getIdentifier());
 172         }
 173
 174         transactionContextAdapter.executePriorTransactionOperations(localTransactionContext);
 175     }
 176
 177     private TransactionContext createValidTransactionContext(CreateTransactionReply reply) {
 178         LOG.debug("Tx {} Received {}", getIdentifier(), reply);
 179
 180         return createValidTransactionContext(getActorContext().actorSelection(reply.getTransactionPath()),
 181                 reply.getTransactionPath(), reply.getVersion());
 182     }
 183
 184     private TransactionContext createValidTransactionContext(ActorSelection transactionActor, String transactionPath,
 185             short remoteTransactionVersion) {
 186         // TxActor is always created where the leader of the shard is.
 187         // Check if TxActor is created in the same node
 188         boolean isTxActorLocal = getActorContext().isPathLocal(transactionPath);
 189         final TransactionContext ret;
 190
 191         if (remoteTransactionVersion < DataStoreVersions.LITHIUM_VERSION) {
 192             ret = new PreLithiumTransactionContextImpl(transactionContextAdapter.getIdentifier(), transactionPath, transactionActor,
 193                 getActorContext(), isTxActorLocal, remoteTransactionVersion, transactionContextAdapter.getLimiter());
 194         } else {
 195             ret = new RemoteTransactionContext(transactionContextAdapter.getIdentifier(), transactionActor, getActorContext(),
 196                 isTxActorLocal, remoteTransactionVersion, transactionContextAdapter.getLimiter());
 197         }
 198
 199         if(parent.getType() == TransactionType.READ_ONLY) {
 200             TransactionContextCleanup.track(this, ret);
 201         }
 202
 203         return ret;
 204     }
 205 }
 206