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 ModifyTransactionSuccess cachedModifySuccess;
  77     private DataTreeModification sealedModification;
  78     private ShardDataTreeCohort readyCohort;
  79
  80     private FrontendTransaction(final AbstractFrontendHistory history, final TransactionIdentifier id,
  81             final ReadWriteShardDataTreeTransaction transaction) {
  82         this.history = Preconditions.checkNotNull(history);
  83         this.id = Preconditions.checkNotNull(id);
  84         this.openTransaction = Preconditions.checkNotNull(transaction);
  85     }
  86
  87     private FrontendTransaction(final AbstractFrontendHistory history, final TransactionIdentifier id,
  88             final DataTreeModification mod) {
  89         this.history = Preconditions.checkNotNull(history);
  90         this.id = Preconditions.checkNotNull(id);
  91         this.sealedModification = Preconditions.checkNotNull(mod);
  92     }
  93
  94     static FrontendTransaction createOpen(final AbstractFrontendHistory history,
  95             final ReadWriteShardDataTreeTransaction transaction) {
  96         return new FrontendTransaction(history, transaction.getIdentifier(), transaction);
  97     }
  98
  99     static FrontendTransaction createReady(final AbstractFrontendHistory history, final TransactionIdentifier id,
 100             final DataTreeModification mod) {
 101         return new FrontendTransaction(history, id, mod);
 102     }
 103
 104     java.util.Optional<TransactionSuccess<?>> replaySequence(final long sequence) throws RequestException {
 105         // Fast path check: if the requested sequence is the next request, bail early
 106         if (expectedSequence == sequence) {
 107             return java.util.Optional.empty();
 108         }
 109
 110         // Check sequencing: we do not need to bother with future requests
 111         if (Long.compareUnsigned(expectedSequence, sequence) < 0) {
 112             throw new OutOfOrderRequestException(expectedSequence);
 113         }
 114
 115         // Sanity check: if we have purged sequences, this has to be newer
 116         if (lastPurgedSequence != null && Long.compareUnsigned(lastPurgedSequence.longValue(), sequence) >= 0) {
 117             // Client has sent a request sequence, which has already been purged. This is a hard error, which should
 118             // never occur. Throwing an IllegalArgumentException will cause it to be wrapped in a
 119             // RuntimeRequestException (which is not retriable) and report it back to the client.
 120             throw new IllegalArgumentException(String.format("Invalid purged sequence %s (last purged is %s)",
 121                 sequence, lastPurgedSequence));
 122         }
 123
 124         // At this point we have established that the requested sequence lies in the open interval
 125         // (lastPurgedSequence, expectedSequence). That does not actually mean we have a response, as the commit
 126         // machinery is asynchronous, hence a reply may be in the works and not available.
 127
 128         long replaySequence = firstReplaySequence;
 129         final Iterator<?> it = replayQueue.iterator();
 130         while (it.hasNext()) {
 131             final Object replay = it.next();
 132             if (replaySequence == sequence) {
 133                 if (replay instanceof RequestException) {
 134                     throw (RequestException) replay;
 135                 }
 136
 137                 Verify.verify(replay instanceof TransactionSuccess);
 138                 return java.util.Optional.of((TransactionSuccess<?>) replay);
 139             }
 140
 141             replaySequence++;
 142         }
 143
 144         // Not found
 145         return java.util.Optional.empty();
 146     }
 147
 148     void purgeSequencesUpTo(final long sequence) {
 149         // FIXME: implement this
 150
 151         lastPurgedSequence = sequence;
 152     }
 153
 154     // Sequence has already been checked
 155     @Nullable TransactionSuccess<?> handleRequest(final TransactionRequest<?> request, final RequestEnvelope envelope,
 156             final long now) throws RequestException {
 157         if (request instanceof ModifyTransactionRequest) {
 158             return handleModifyTransaction((ModifyTransactionRequest) request, envelope, now);
 159         } else if (request instanceof CommitLocalTransactionRequest) {
 160             handleCommitLocalTransaction((CommitLocalTransactionRequest) request, envelope, now);
 161             return null;
 162         } else if (request instanceof ExistsTransactionRequest) {
 163             return handleExistsTransaction((ExistsTransactionRequest) request);
 164         } else if (request instanceof ReadTransactionRequest) {
 165             return handleReadTransaction((ReadTransactionRequest) request);
 166         } else if (request instanceof TransactionPreCommitRequest) {
 167             handleTransactionPreCommit((TransactionPreCommitRequest) request, envelope, now);
 168             return null;
 169         } else if (request instanceof TransactionDoCommitRequest) {
 170             handleTransactionDoCommit((TransactionDoCommitRequest) request, envelope, now);
 171             return null;
 172         } else if (request instanceof TransactionAbortRequest) {
 173             return handleTransactionAbort((TransactionAbortRequest) request, envelope, now);
 174         } else {
 175             throw new UnsupportedRequestException(request);
 176         }
 177     }
 178
 179     private void recordResponse(final long sequence, final Object response) {
 180         if (replayQueue.isEmpty()) {
 181             firstReplaySequence = sequence;
 182         }
 183         replayQueue.add(response);
 184         expectedSequence++;
 185     }
 186
 187     private <T extends TransactionSuccess<?>> T recordSuccess(final long sequence, final T success) {
 188         recordResponse(sequence, success);
 189         return success;
 190     }
 191
 192     private long executionTime(final long startTime) {
 193         return history.readTime() - startTime;
 194     }
 195
 196     private void recordAndSendSuccess(final RequestEnvelope envelope, final long startTime,
 197             final TransactionSuccess<?> success) {
 198         recordResponse(success.getSequence(), success);
 199         envelope.sendSuccess(success, executionTime(startTime));
 200     }
 201
 202     private void recordAndSendFailure(final RequestEnvelope envelope, final long startTime,
 203             final RuntimeRequestException failure) {
 204         recordResponse(envelope.getMessage().getSequence(), failure);
 205         envelope.sendFailure(failure, executionTime(startTime));
 206     }
 207
 208     private void handleTransactionPreCommit(final TransactionPreCommitRequest request,
 209             final RequestEnvelope envelope, final long now) throws RequestException {
 210         readyCohort.preCommit(new FutureCallback<DataTreeCandidate>() {
 211             @Override
 212             public void onSuccess(final DataTreeCandidate result) {
 213                 recordAndSendSuccess(envelope, now, new TransactionPreCommitSuccess(readyCohort.getIdentifier(),
 214                     request.getSequence()));
 215             }
 216
 217             @Override
 218             public void onFailure(final Throwable failure) {
 219                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Precommit failed", failure));
 220                 readyCohort = null;
 221             }
 222         });
 223     }
 224
 225     private void handleTransactionDoCommit(final TransactionDoCommitRequest request, final RequestEnvelope envelope,
 226             final long now) throws RequestException {
 227         readyCohort.commit(new FutureCallback<UnsignedLong>() {
 228             @Override
 229             public void onSuccess(final UnsignedLong result) {
 230                 successfulCommit(envelope, now);
 231             }
 232
 233             @Override
 234             public void onFailure(final Throwable failure) {
 235                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Commit failed", failure));
 236                 readyCohort = null;
 237             }
 238         });
 239     }
 240
 241     private TransactionSuccess<?> handleTransactionAbort(final TransactionAbortRequest request,
 242             final RequestEnvelope envelope, final long now) throws RequestException {
 243         if (readyCohort == null) {
 244             openTransaction.abort();
 245             return new TransactionAbortSuccess(id, request.getSequence());
 246         }
 247
 248         readyCohort.abort(new FutureCallback<Void>() {
 249             @Override
 250             public void onSuccess(final Void result) {
 251                 readyCohort = null;
 252                 recordAndSendSuccess(envelope, now, new TransactionAbortSuccess(id, request.getSequence()));
 253                 LOG.debug("Transaction {} aborted", id);
 254             }
 255
 256             @Override
 257             public void onFailure(final Throwable failure) {
 258                 readyCohort = null;
 259                 LOG.warn("Transaction {} abort failed", id, failure);
 260                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Abort failed", failure));
 261             }
 262         });
 263         return null;
 264     }
 265
 266     private void coordinatedCommit(final RequestEnvelope envelope, final long now) {
 267         readyCohort.canCommit(new FutureCallback<Void>() {
 268             @Override
 269             public void onSuccess(final Void result) {
 270                 recordAndSendSuccess(envelope, now, new TransactionCanCommitSuccess(readyCohort.getIdentifier(),
 271                     envelope.getMessage().getSequence()));
 272             }
 273
 274             @Override
 275             public void onFailure(final Throwable failure) {
 276                 recordAndSendFailure(envelope, now, new RuntimeRequestException("CanCommit failed", failure));
 277                 readyCohort = null;
 278             }
 279         });
 280     }
 281
 282     private void directCommit(final RequestEnvelope envelope, final long now) {
 283         readyCohort.canCommit(new FutureCallback<Void>() {
 284             @Override
 285             public void onSuccess(final Void result) {
 286                 successfulDirectCanCommit(envelope, now);
 287             }
 288
 289             @Override
 290             public void onFailure(final Throwable failure) {
 291                 recordAndSendFailure(envelope, now, new RuntimeRequestException("CanCommit failed", failure));
 292                 readyCohort = null;
 293             }
 294         });
 295
 296     }
 297
 298     private void successfulDirectCanCommit(final RequestEnvelope envelope, final long startTime) {
 299         readyCohort.preCommit(new FutureCallback<DataTreeCandidate>() {
 300             @Override
 301             public void onSuccess(final DataTreeCandidate result) {
 302                 successfulDirectPreCommit(envelope, startTime);
 303             }
 304
 305             @Override
 306             public void onFailure(final Throwable failure) {
 307                 recordAndSendFailure(envelope, startTime, new RuntimeRequestException("PreCommit failed", failure));
 308                 readyCohort = null;
 309             }
 310         });
 311     }
 312
 313     private void successfulDirectPreCommit(final RequestEnvelope envelope, final long startTime) {
 314         readyCohort.commit(new FutureCallback<UnsignedLong>() {
 315
 316             @Override
 317             public void onSuccess(final UnsignedLong result) {
 318                 successfulCommit(envelope, startTime);
 319             }
 320
 321             @Override
 322             public void onFailure(final Throwable failure) {
 323                 recordAndSendFailure(envelope, startTime, new RuntimeRequestException("DoCommit failed", failure));
 324                 readyCohort = null;
 325             }
 326         });
 327     }
 328
 329     private void successfulCommit(final RequestEnvelope envelope, final long startTime) {
 330         recordAndSendSuccess(envelope, startTime, new TransactionCommitSuccess(readyCohort.getIdentifier(),
 331             envelope.getMessage().getSequence()));
 332         readyCohort = null;
 333     }
 334
 335     private void handleCommitLocalTransaction(final CommitLocalTransactionRequest request,
 336             final RequestEnvelope envelope, final long now) throws RequestException {
 337         if (sealedModification.equals(request.getModification())) {
 338             readyCohort = history.createReadyCohort(id, sealedModification);
 339
 340             if (request.isCoordinated()) {
 341                 coordinatedCommit(envelope, now);
 342             } else {
 343                 directCommit(envelope, now);
 344             }
 345         } else {
 346             throw new UnsupportedRequestException(request);
 347         }
 348     }
 349
 350     private ExistsTransactionSuccess handleExistsTransaction(final ExistsTransactionRequest request)
 351             throws RequestException {
 352         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
 353         return recordSuccess(request.getSequence(), new ExistsTransactionSuccess(id, request.getSequence(),
 354             data.isPresent()));
 355     }
 356
 357     private ReadTransactionSuccess handleReadTransaction(final ReadTransactionRequest request)
 358             throws RequestException {
 359         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
 360         return recordSuccess(request.getSequence(), new ReadTransactionSuccess(id, request.getSequence(), data));
 361     }
 362
 363     private ModifyTransactionSuccess replyModifySuccess(final long sequence) {
 364         if (cachedModifySuccess == null) {
 365             cachedModifySuccess = new ModifyTransactionSuccess(id, sequence);
 366         }
 367
 368         return recordSuccess(sequence, cachedModifySuccess);
 369     }
 370
 371     private @Nullable TransactionSuccess<?> handleModifyTransaction(final ModifyTransactionRequest request,
 372             final RequestEnvelope envelope, final long now) throws RequestException {
 373
 374         final DataTreeModification modification = openTransaction.getSnapshot();
 375         for (TransactionModification m : request.getModifications()) {
 376             if (m instanceof TransactionDelete) {
 377                 modification.delete(m.getPath());
 378             } else if (m instanceof TransactionWrite) {
 379                 modification.write(m.getPath(), ((TransactionWrite) m).getData());
 380             } else if (m instanceof TransactionMerge) {
 381                 modification.merge(m.getPath(), ((TransactionMerge) m).getData());
 382             } else {
 383                 LOG.warn("{}: ignoring unhandled modification {}", history.persistenceId(), m);
 384             }
 385         }
 386
 387         final java.util.Optional<PersistenceProtocol> maybeProto = request.getPersistenceProtocol();
 388         if (!maybeProto.isPresent()) {
 389             return replyModifySuccess(request.getSequence());
 390         }
 391
 392         switch (maybeProto.get()) {
 393             case ABORT:
 394                 openTransaction.abort();
 395                 openTransaction = null;
 396                 return replyModifySuccess(request.getSequence());
 397             case SIMPLE:
 398                 readyCohort = openTransaction.ready();
 399                 openTransaction = null;
 400                 directCommit(envelope, now);
 401                 return null;
 402             case THREE_PHASE:
 403                 readyCohort = openTransaction.ready();
 404                 openTransaction = null;
 405                 coordinatedCommit(envelope, now);
 406                 return null;
 407             default:
 408                 throw new UnsupportedRequestException(request);
 409         }
 410     }
 411 }