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

   1 /*
   2  * Copyright (c) 2016 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 package org.opendaylight.controller.cluster.datastore;
   9
  10 import com.google.common.base.Optional;
  11 import com.google.common.base.Preconditions;
  12 import com.google.common.base.Verify;
  13 import com.google.common.primitives.UnsignedLong;
  14 import com.google.common.util.concurrent.FutureCallback;
  15 import java.util.ArrayDeque;
  16 import java.util.Iterator;
  17 import java.util.Queue;
  18 import javax.annotation.Nullable;
  19 import javax.annotation.concurrent.NotThreadSafe;
  20 import org.opendaylight.controller.cluster.access.commands.CommitLocalTransactionRequest;
  21 import org.opendaylight.controller.cluster.access.commands.ExistsTransactionRequest;
  22 import org.opendaylight.controller.cluster.access.commands.ExistsTransactionSuccess;
  23 import org.opendaylight.controller.cluster.access.commands.ModifyTransactionRequest;
  24 import org.opendaylight.controller.cluster.access.commands.ModifyTransactionSuccess;
  25 import org.opendaylight.controller.cluster.access.commands.OutOfOrderRequestException;
  26 import org.opendaylight.controller.cluster.access.commands.PersistenceProtocol;
  27 import org.opendaylight.controller.cluster.access.commands.ReadTransactionRequest;
  28 import org.opendaylight.controller.cluster.access.commands.ReadTransactionSuccess;
  29 import org.opendaylight.controller.cluster.access.commands.TransactionAbortRequest;
  30 import org.opendaylight.controller.cluster.access.commands.TransactionAbortSuccess;
  31 import org.opendaylight.controller.cluster.access.commands.TransactionCanCommitSuccess;
  32 import org.opendaylight.controller.cluster.access.commands.TransactionCommitSuccess;
  33 import org.opendaylight.controller.cluster.access.commands.TransactionDelete;
  34 import org.opendaylight.controller.cluster.access.commands.TransactionDoCommitRequest;
  35 import org.opendaylight.controller.cluster.access.commands.TransactionMerge;
  36 import org.opendaylight.controller.cluster.access.commands.TransactionModification;
  37 import org.opendaylight.controller.cluster.access.commands.TransactionPreCommitRequest;
  38 import org.opendaylight.controller.cluster.access.commands.TransactionPreCommitSuccess;
  39 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
  40 import org.opendaylight.controller.cluster.access.commands.TransactionSuccess;
  41 import org.opendaylight.controller.cluster.access.commands.TransactionWrite;
  42 import org.opendaylight.controller.cluster.access.concepts.RequestEnvelope;
  43 import org.opendaylight.controller.cluster.access.concepts.RequestException;
  44 import org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException;
  45 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  46 import org.opendaylight.controller.cluster.access.concepts.UnsupportedRequestException;
  47 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  48 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  49 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
  50 import org.slf4j.Logger;
  51 import org.slf4j.LoggerFactory;
  52
  53 /**
  54  * Frontend transaction state as observed by the shard leader.
  55  *
  56  * @author Robert Varga
  57  */
  58 @NotThreadSafe
  59 final class FrontendTransaction {
  60     private static final Logger LOG = LoggerFactory.getLogger(FrontendTransaction.class);
  61
  62     private final AbstractFrontendHistory history;
  63     private final TransactionIdentifier id;
  64
  65     /**
  66      * It is possible that after we process a request and send a response that response gets lost and the client
  67      * initiates a retry. Since subsequent requests can mutate transaction state we need to retain the response until
  68      * it is acknowledged by the client.
  69      */
  70     private final Queue<Object> replayQueue = new ArrayDeque<>();
  71     private long firstReplaySequence;
  72     private Long lastPurgedSequence;
  73     private long expectedSequence;
  74
  75     private ReadWriteShardDataTreeTransaction openTransaction;
  76     private DataTreeModification sealedModification;
  77     private ShardDataTreeCohort readyCohort;
  78
  79     private FrontendTransaction(final AbstractFrontendHistory history, final TransactionIdentifier id,
  80             final ReadWriteShardDataTreeTransaction transaction) {
  81         this.history = Preconditions.checkNotNull(history);
  82         this.id = Preconditions.checkNotNull(id);
  83         this.openTransaction = Preconditions.checkNotNull(transaction);
  84     }
  85
  86     private FrontendTransaction(final AbstractFrontendHistory history, final TransactionIdentifier id,
  87             final DataTreeModification mod) {
  88         this.history = Preconditions.checkNotNull(history);
  89         this.id = Preconditions.checkNotNull(id);
  90         this.sealedModification = Preconditions.checkNotNull(mod);
  91     }
  92
  93     static FrontendTransaction createOpen(final AbstractFrontendHistory history,
  94             final ReadWriteShardDataTreeTransaction transaction) {
  95         return new FrontendTransaction(history, transaction.getIdentifier(), transaction);
  96     }
  97
  98     static FrontendTransaction createReady(final AbstractFrontendHistory history, final TransactionIdentifier id,
  99             final DataTreeModification mod) {
 100         return new FrontendTransaction(history, id, mod);
 101     }
 102
 103     java.util.Optional<TransactionSuccess<?>> replaySequence(final long sequence) throws RequestException {
 104         // Fast path check: if the requested sequence is the next request, bail early
 105         if (expectedSequence == sequence) {
 106             return java.util.Optional.empty();
 107         }
 108
 109         // Check sequencing: we do not need to bother with future requests
 110         if (Long.compareUnsigned(expectedSequence, sequence) < 0) {
 111             throw new OutOfOrderRequestException(expectedSequence);
 112         }
 113
 114         // Sanity check: if we have purged sequences, this has to be newer
 115         if (lastPurgedSequence != null && Long.compareUnsigned(lastPurgedSequence.longValue(), sequence) >= 0) {
 116             // Client has sent a request sequence, which has already been purged. This is a hard error, which should
 117             // never occur. Throwing an IllegalArgumentException will cause it to be wrapped in a
 118             // RuntimeRequestException (which is not retriable) and report it back to the client.
 119             throw new IllegalArgumentException(String.format("Invalid purged sequence %s (last purged is %s)",
 120                 sequence, lastPurgedSequence));
 121         }
 122
 123         // At this point we have established that the requested sequence lies in the open interval
 124         // (lastPurgedSequence, expectedSequence). That does not actually mean we have a response, as the commit
 125         // machinery is asynchronous, hence a reply may be in the works and not available.
 126
 127         long replaySequence = firstReplaySequence;
 128         final Iterator<?> it = replayQueue.iterator();
 129         while (it.hasNext()) {
 130             final Object replay = it.next();
 131             if (replaySequence == sequence) {
 132                 if (replay instanceof RequestException) {
 133                     throw (RequestException) replay;
 134                 }
 135
 136                 Verify.verify(replay instanceof TransactionSuccess);
 137                 return java.util.Optional.of((TransactionSuccess<?>) replay);
 138             }
 139
 140             replaySequence++;
 141         }
 142
 143         // Not found
 144         return java.util.Optional.empty();
 145     }
 146
 147     void purgeSequencesUpTo(final long sequence) {
 148         // FIXME: implement this
 149
 150         lastPurgedSequence = sequence;
 151     }
 152
 153     // Sequence has already been checked
 154     @Nullable TransactionSuccess<?> handleRequest(final TransactionRequest<?> request, final RequestEnvelope envelope,
 155             final long now) throws RequestException {
 156         if (request instanceof ModifyTransactionRequest) {
 157             return handleModifyTransaction((ModifyTransactionRequest) request, envelope, now);
 158         } else if (request instanceof CommitLocalTransactionRequest) {
 159             handleCommitLocalTransaction((CommitLocalTransactionRequest) request, envelope, now);
 160             return null;
 161         } else if (request instanceof ExistsTransactionRequest) {
 162             return handleExistsTransaction((ExistsTransactionRequest) request);
 163         } else if (request instanceof ReadTransactionRequest) {
 164             return handleReadTransaction((ReadTransactionRequest) request);
 165         } else if (request instanceof TransactionPreCommitRequest) {
 166             handleTransactionPreCommit((TransactionPreCommitRequest) request, envelope, now);
 167             return null;
 168         } else if (request instanceof TransactionDoCommitRequest) {
 169             handleTransactionDoCommit((TransactionDoCommitRequest) request, envelope, now);
 170             return null;
 171         } else if (request instanceof TransactionAbortRequest) {
 172             return handleTransactionAbort((TransactionAbortRequest) request, envelope, now);
 173         } else {
 174             throw new UnsupportedRequestException(request);
 175         }
 176     }
 177
 178     private void recordResponse(final long sequence, final Object response) {
 179         if (replayQueue.isEmpty()) {
 180             firstReplaySequence = sequence;
 181         }
 182         replayQueue.add(response);
 183         expectedSequence++;
 184     }
 185
 186     private <T extends TransactionSuccess<?>> T recordSuccess(final long sequence, final T success) {
 187         recordResponse(sequence, success);
 188         return success;
 189     }
 190
 191     private long executionTime(final long startTime) {
 192         return history.readTime() - startTime;
 193     }
 194
 195     private void recordAndSendSuccess(final RequestEnvelope envelope, final long startTime,
 196             final TransactionSuccess<?> success) {
 197         recordResponse(success.getSequence(), success);
 198         envelope.sendSuccess(success, executionTime(startTime));
 199     }
 200
 201     private void recordAndSendFailure(final RequestEnvelope envelope, final long startTime,
 202             final RuntimeRequestException failure) {
 203         recordResponse(envelope.getMessage().getSequence(), failure);
 204         envelope.sendFailure(failure, executionTime(startTime));
 205     }
 206
 207     private void handleTransactionPreCommit(final TransactionPreCommitRequest request,
 208             final RequestEnvelope envelope, final long now) throws RequestException {
 209         readyCohort.preCommit(new FutureCallback<DataTreeCandidate>() {
 210             @Override
 211             public void onSuccess(final DataTreeCandidate result) {
 212                 recordAndSendSuccess(envelope, now, new TransactionPreCommitSuccess(readyCohort.getIdentifier(),
 213                     request.getSequence()));
 214             }
 215
 216             @Override
 217             public void onFailure(final Throwable failure) {
 218                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Precommit failed", failure));
 219                 readyCohort = null;
 220             }
 221         });
 222     }
 223
 224     private void handleTransactionDoCommit(final TransactionDoCommitRequest request, final RequestEnvelope envelope,
 225             final long now) throws RequestException {
 226         readyCohort.commit(new FutureCallback<UnsignedLong>() {
 227             @Override
 228             public void onSuccess(final UnsignedLong result) {
 229                 successfulCommit(envelope, now);
 230             }
 231
 232             @Override
 233             public void onFailure(final Throwable failure) {
 234                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Commit failed", failure));
 235                 readyCohort = null;
 236             }
 237         });
 238     }
 239
 240     private TransactionSuccess<?> handleTransactionAbort(final TransactionAbortRequest request,
 241             final RequestEnvelope envelope, final long now) throws RequestException {
 242         if (readyCohort == null) {
 243             openTransaction.abort();
 244             return new TransactionAbortSuccess(id, request.getSequence());
 245         }
 246
 247         readyCohort.abort(new FutureCallback<Void>() {
 248             @Override
 249             public void onSuccess(final Void result) {
 250                 readyCohort = null;
 251                 recordAndSendSuccess(envelope, now, new TransactionAbortSuccess(id, request.getSequence()));
 252                 LOG.debug("Transaction {} aborted", id);
 253             }
 254
 255             @Override
 256             public void onFailure(final Throwable failure) {
 257                 readyCohort = null;
 258                 LOG.warn("Transaction {} abort failed", id, failure);
 259                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Abort failed", failure));
 260             }
 261         });
 262         return null;
 263     }
 264
 265     private void coordinatedCommit(final RequestEnvelope envelope, final long now) {
 266         readyCohort.canCommit(new FutureCallback<Void>() {
 267             @Override
 268             public void onSuccess(final Void result) {
 269                 recordAndSendSuccess(envelope, now, new TransactionCanCommitSuccess(readyCohort.getIdentifier(),
 270                     envelope.getMessage().getSequence()));
 271             }
 272
 273             @Override
 274             public void onFailure(final Throwable failure) {
 275                 recordAndSendFailure(envelope, now, new RuntimeRequestException("CanCommit failed", failure));
 276                 readyCohort = null;
 277             }
 278         });
 279     }
 280
 281     private void directCommit(final RequestEnvelope envelope, final long now) {
 282         readyCohort.canCommit(new FutureCallback<Void>() {
 283             @Override
 284             public void onSuccess(final Void result) {
 285                 successfulDirectCanCommit(envelope, now);
 286             }
 287
 288             @Override
 289             public void onFailure(final Throwable failure) {
 290                 recordAndSendFailure(envelope, now, new RuntimeRequestException("CanCommit failed", failure));
 291                 readyCohort = null;
 292             }
 293         });
 294
 295     }
 296
 297     private void successfulDirectCanCommit(final RequestEnvelope envelope, final long startTime) {
 298         readyCohort.preCommit(new FutureCallback<DataTreeCandidate>() {
 299             @Override
 300             public void onSuccess(final DataTreeCandidate result) {
 301                 successfulDirectPreCommit(envelope, startTime);
 302             }
 303
 304             @Override
 305             public void onFailure(final Throwable failure) {
 306                 recordAndSendFailure(envelope, startTime, new RuntimeRequestException("PreCommit failed", failure));
 307                 readyCohort = null;
 308             }
 309         });
 310     }
 311
 312     private void successfulDirectPreCommit(final RequestEnvelope envelope, final long startTime) {
 313         readyCohort.commit(new FutureCallback<UnsignedLong>() {
 314
 315             @Override
 316             public void onSuccess(final UnsignedLong result) {
 317                 successfulCommit(envelope, startTime);
 318             }
 319
 320             @Override
 321             public void onFailure(final Throwable failure) {
 322                 recordAndSendFailure(envelope, startTime, new RuntimeRequestException("DoCommit failed", failure));
 323                 readyCohort = null;
 324             }
 325         });
 326     }
 327
 328     private void successfulCommit(final RequestEnvelope envelope, final long startTime) {
 329         recordAndSendSuccess(envelope, startTime, new TransactionCommitSuccess(readyCohort.getIdentifier(),
 330             envelope.getMessage().getSequence()));
 331         readyCohort = null;
 332     }
 333
 334     private void handleCommitLocalTransaction(final CommitLocalTransactionRequest request,
 335             final RequestEnvelope envelope, final long now) throws RequestException {
 336         if (sealedModification.equals(request.getModification())) {
 337             readyCohort = history.createReadyCohort(id, sealedModification);
 338
 339             if (request.isCoordinated()) {
 340                 coordinatedCommit(envelope, now);
 341             } else {
 342                 directCommit(envelope, now);
 343             }
 344         } else {
 345             throw new UnsupportedRequestException(request);
 346         }
 347     }
 348
 349     private ExistsTransactionSuccess handleExistsTransaction(final ExistsTransactionRequest request)
 350             throws RequestException {
 351         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
 352         return recordSuccess(request.getSequence(), new ExistsTransactionSuccess(id, request.getSequence(),
 353             data.isPresent()));
 354     }
 355
 356     private ReadTransactionSuccess handleReadTransaction(final ReadTransactionRequest request)
 357             throws RequestException {
 358         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
 359         return recordSuccess(request.getSequence(), new ReadTransactionSuccess(id, request.getSequence(), data));
 360     }
 361
 362     private ModifyTransactionSuccess replyModifySuccess(final long sequence) {
 363         return recordSuccess(sequence, new ModifyTransactionSuccess(id, sequence));
 364     }
 365
 366     private @Nullable TransactionSuccess<?> handleModifyTransaction(final ModifyTransactionRequest request,
 367             final RequestEnvelope envelope, final long now) throws RequestException {
 368
 369         final DataTreeModification modification = openTransaction.getSnapshot();
 370         for (TransactionModification m : request.getModifications()) {
 371             if (m instanceof TransactionDelete) {
 372                 modification.delete(m.getPath());
 373             } else if (m instanceof TransactionWrite) {
 374                 modification.write(m.getPath(), ((TransactionWrite) m).getData());
 375             } else if (m instanceof TransactionMerge) {
 376                 modification.merge(m.getPath(), ((TransactionMerge) m).getData());
 377             } else {
 378                 LOG.warn("{}: ignoring unhandled modification {}", history.persistenceId(), m);
 379             }
 380         }
 381
 382         final java.util.Optional<PersistenceProtocol> maybeProto = request.getPersistenceProtocol();
 383         if (!maybeProto.isPresent()) {
 384             return replyModifySuccess(request.getSequence());
 385         }
 386
 387         switch (maybeProto.get()) {
 388             case ABORT:
 389                 openTransaction.abort();
 390                 openTransaction = null;
 391                 return replyModifySuccess(request.getSequence());
 392             case SIMPLE:
 393                 readyCohort = openTransaction.ready();
 394                 openTransaction = null;
 395                 directCommit(envelope, now);
 396                 return null;
 397             case THREE_PHASE:
 398                 readyCohort = openTransaction.ready();
 399                 openTransaction = null;
 400                 coordinatedCommit(envelope, now);
 401                 return null;
 402             default:
 403                 throw new UnsupportedRequestException(request);
 404         }
 405     }
 406 }