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             handleTransactionAbort((TransactionAbortRequest) request, envelope, now);
 174             return null;
 175         } else {
 176             throw new UnsupportedRequestException(request);
 177         }
 178     }
 179
 180     private void recordResponse(final long sequence, final Object response) {
 181         if (replayQueue.isEmpty()) {
 182             firstReplaySequence = sequence;
 183         }
 184         replayQueue.add(response);
 185         expectedSequence++;
 186     }
 187
 188     private <T extends TransactionSuccess<?>> T recordSuccess(final long sequence, final T success) {
 189         recordResponse(sequence, success);
 190         return success;
 191     }
 192
 193     private long executionTime(final long startTime) {
 194         return history.readTime() - startTime;
 195     }
 196
 197     private void recordAndSendSuccess(final RequestEnvelope envelope, final long startTime,
 198             final TransactionSuccess<?> success) {
 199         recordResponse(success.getSequence(), success);
 200         envelope.sendSuccess(success, executionTime(startTime));
 201     }
 202
 203     private void recordAndSendFailure(final RequestEnvelope envelope, final long startTime,
 204             final RuntimeRequestException failure) {
 205         recordResponse(envelope.getMessage().getSequence(), failure);
 206         envelope.sendFailure(failure, executionTime(startTime));
 207     }
 208
 209     private void handleTransactionPreCommit(final TransactionPreCommitRequest request,
 210             final RequestEnvelope envelope, final long now) throws RequestException {
 211         readyCohort.preCommit(new FutureCallback<DataTreeCandidate>() {
 212             @Override
 213             public void onSuccess(final DataTreeCandidate result) {
 214                 recordAndSendSuccess(envelope, now, new TransactionPreCommitSuccess(readyCohort.getIdentifier(),
 215                     request.getSequence()));
 216             }
 217
 218             @Override
 219             public void onFailure(final Throwable failure) {
 220                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Precommit failed", failure));
 221                 readyCohort = null;
 222             }
 223         });
 224     }
 225
 226     private void handleTransactionDoCommit(final TransactionDoCommitRequest request, final RequestEnvelope envelope,
 227             final long now) throws RequestException {
 228         readyCohort.commit(new FutureCallback<UnsignedLong>() {
 229             @Override
 230             public void onSuccess(final UnsignedLong result) {
 231                 successfulCommit(envelope, now);
 232             }
 233
 234             @Override
 235             public void onFailure(final Throwable failure) {
 236                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Commit failed", failure));
 237                 readyCohort = null;
 238             }
 239         });
 240     }
 241
 242     private void handleTransactionAbort(final TransactionAbortRequest request, final RequestEnvelope envelope,
 243             final long now) throws RequestException {
 244         readyCohort.abort(new FutureCallback<Void>() {
 245             @Override
 246             public void onSuccess(final Void result) {
 247                 readyCohort = null;
 248                 recordAndSendSuccess(envelope, now, new TransactionAbortSuccess(id, request.getSequence()));
 249                 LOG.debug("Transaction {} aborted", id);
 250             }
 251
 252             @Override
 253             public void onFailure(final Throwable failure) {
 254                 readyCohort = null;
 255                 LOG.warn("Transaction {} abort failed", id, failure);
 256                 recordAndSendFailure(envelope, now, new RuntimeRequestException("Abort failed", failure));
 257             }
 258         });
 259     }
 260
 261     private void coordinatedCommit(final RequestEnvelope envelope, final long now) {
 262         readyCohort.canCommit(new FutureCallback<Void>() {
 263             @Override
 264             public void onSuccess(final Void result) {
 265                 recordAndSendSuccess(envelope, now, new TransactionCanCommitSuccess(readyCohort.getIdentifier(),
 266                     envelope.getMessage().getSequence()));
 267             }
 268
 269             @Override
 270             public void onFailure(final Throwable failure) {
 271                 recordAndSendFailure(envelope, now, new RuntimeRequestException("CanCommit failed", failure));
 272                 readyCohort = null;
 273             }
 274         });
 275     }
 276
 277     private void directCommit(final RequestEnvelope envelope, final long now) {
 278         readyCohort.canCommit(new FutureCallback<Void>() {
 279             @Override
 280             public void onSuccess(final Void result) {
 281                 successfulDirectCanCommit(envelope, now);
 282             }
 283
 284             @Override
 285             public void onFailure(final Throwable failure) {
 286                 recordAndSendFailure(envelope, now, new RuntimeRequestException("CanCommit failed", failure));
 287                 readyCohort = null;
 288             }
 289         });
 290
 291     }
 292
 293     private void successfulDirectCanCommit(final RequestEnvelope envelope, final long startTime) {
 294         readyCohort.preCommit(new FutureCallback<DataTreeCandidate>() {
 295             @Override
 296             public void onSuccess(final DataTreeCandidate result) {
 297                 successfulDirectPreCommit(envelope, startTime);
 298             }
 299
 300             @Override
 301             public void onFailure(final Throwable failure) {
 302                 recordAndSendFailure(envelope, startTime, new RuntimeRequestException("PreCommit failed", failure));
 303                 readyCohort = null;
 304             }
 305         });
 306     }
 307
 308     private void successfulDirectPreCommit(final RequestEnvelope envelope, final long startTime) {
 309         readyCohort.commit(new FutureCallback<UnsignedLong>() {
 310
 311             @Override
 312             public void onSuccess(final UnsignedLong result) {
 313                 successfulCommit(envelope, startTime);
 314             }
 315
 316             @Override
 317             public void onFailure(final Throwable failure) {
 318                 recordAndSendFailure(envelope, startTime, new RuntimeRequestException("DoCommit failed", failure));
 319                 readyCohort = null;
 320             }
 321         });
 322     }
 323
 324     private void successfulCommit(final RequestEnvelope envelope, final long startTime) {
 325         recordAndSendSuccess(envelope, startTime, new TransactionCommitSuccess(readyCohort.getIdentifier(),
 326             envelope.getMessage().getSequence()));
 327         readyCohort = null;
 328     }
 329
 330     private void handleCommitLocalTransaction(final CommitLocalTransactionRequest request,
 331             final RequestEnvelope envelope, final long now) throws RequestException {
 332         if (sealedModification.equals(request.getModification())) {
 333             readyCohort = history.createReadyCohort(id, sealedModification);
 334
 335             if (request.isCoordinated()) {
 336                 coordinatedCommit(envelope, now);
 337             } else {
 338                 directCommit(envelope, now);
 339             }
 340         } else {
 341             throw new UnsupportedRequestException(request);
 342         }
 343     }
 344
 345     private ExistsTransactionSuccess handleExistsTransaction(final ExistsTransactionRequest request)
 346             throws RequestException {
 347         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
 348         return recordSuccess(request.getSequence(), new ExistsTransactionSuccess(id, request.getSequence(),
 349             data.isPresent()));
 350     }
 351
 352     private ReadTransactionSuccess handleReadTransaction(final ReadTransactionRequest request)
 353             throws RequestException {
 354         final Optional<NormalizedNode<?, ?>> data = openTransaction.getSnapshot().readNode(request.getPath());
 355         return recordSuccess(request.getSequence(), new ReadTransactionSuccess(id, request.getSequence(), data));
 356     }
 357
 358     private ModifyTransactionSuccess replyModifySuccess(final long sequence) {
 359         if (cachedModifySuccess == null) {
 360             cachedModifySuccess = new ModifyTransactionSuccess(id, sequence);
 361         }
 362
 363         return recordSuccess(sequence, cachedModifySuccess);
 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 }