opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/sharding/DistributedShardChangePublisher.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
   9 package org.opendaylight.controller.cluster.sharding;
  10
  11 import com.google.common.base.Optional;
  12 import com.google.common.base.Preconditions;
  13 import java.util.ArrayList;
  14 import java.util.Collection;
  15 import java.util.Collections;
  16 import java.util.Iterator;
  17 import java.util.LinkedList;
  18 import java.util.List;
  19 import java.util.Map;
  20 import java.util.concurrent.ConcurrentHashMap;
  21 import java.util.stream.Collectors;
  22 import javax.annotation.Nonnull;
  23 import javax.annotation.Nullable;
  24 import javax.annotation.concurrent.GuardedBy;
  25 import org.opendaylight.controller.cluster.databroker.actors.dds.DataStoreClient;
  26 import org.opendaylight.controller.cluster.datastore.AbstractDataStore;
  27 import org.opendaylight.mdsal.dom.api.DOMDataTreeChangeListener;
  28 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
  29 import org.opendaylight.mdsal.dom.spi.AbstractDOMDataTreeChangeListenerRegistration;
  30 import org.opendaylight.mdsal.dom.spi.AbstractRegistrationTree;
  31 import org.opendaylight.mdsal.dom.spi.RegistrationTreeNode;
  32 import org.opendaylight.mdsal.dom.spi.shard.ChildShardContext;
  33 import org.opendaylight.mdsal.dom.spi.store.DOMStoreTreeChangePublisher;
  34 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  35 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  36 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
  37 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  38 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
  39 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  40 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateNode;
  41 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidates;
  42 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
  43 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  44 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  45 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
  46 import org.opendaylight.yangtools.yang.data.impl.schema.tree.InMemoryDataTreeFactory;
  47 import org.opendaylight.yangtools.yang.data.impl.schema.tree.SchemaValidationFailedException;
  48 import org.slf4j.Logger;
  49 import org.slf4j.LoggerFactory;
  50
  51 public class DistributedShardChangePublisher
  52         extends AbstractRegistrationTree<AbstractDOMDataTreeChangeListenerRegistration<?>>
  53         implements DOMStoreTreeChangePublisher {
  54
  55     private static final Logger LOG = LoggerFactory.getLogger(DistributedShardChangePublisher.class);
  56
  57     private final AbstractDataStore distributedDataStore;
  58     private final YangInstanceIdentifier shardPath;
  59
  60     private final Map<DOMDataTreeIdentifier, ChildShardContext> childShards;
  61
  62     @GuardedBy("this")
  63     private final DataTree dataTree;
  64
  65     public DistributedShardChangePublisher(final DataStoreClient client,
  66                                            final AbstractDataStore distributedDataStore,
  67                                            final DOMDataTreeIdentifier prefix,
  68                                            final Map<DOMDataTreeIdentifier, ChildShardContext> childShards) {
  69         this.distributedDataStore = distributedDataStore;
  70         // TODO keeping the whole dataTree thats contained in subshards doesn't seem like a good idea
  71         // maybe the whole listener logic would be better in the backend shards where we have direct access to the
  72         // dataTree and wont have to cache it redundantly.
  73         this.dataTree = InMemoryDataTreeFactory.getInstance().create(
  74                 TreeType.valueOf(prefix.getDatastoreType().name()), prefix.getRootIdentifier());
  75
  76         dataTree.setSchemaContext(distributedDataStore.getActorContext().getSchemaContext());
  77
  78         this.shardPath = prefix.getRootIdentifier();
  79         this.childShards = childShards;
  80     }
  81
  82     protected void registrationRemoved(final AbstractDOMDataTreeChangeListenerRegistration<?> registration) {
  83         LOG.debug("Closing registration {}", registration);
  84     }
  85
  86     @Override
  87     public <L extends DOMDataTreeChangeListener> AbstractDOMDataTreeChangeListenerRegistration<L>
  88             registerTreeChangeListener(final YangInstanceIdentifier path, final L listener) {
  89         takeLock();
  90         try {
  91             return setupListenerContext(path, listener);
  92         } finally {
  93             releaseLock();
  94         }
  95     }
  96
  97     private <L extends DOMDataTreeChangeListener> AbstractDOMDataTreeChangeListenerRegistration<L>
  98             setupListenerContext(final YangInstanceIdentifier listenerPath, final L listener) {
  99         // we need to register the listener registration path based on the shards root
 100         // we have to strip the shard path from the listener path and then register
 101         YangInstanceIdentifier strippedIdentifier = listenerPath;
 102         if (!shardPath.isEmpty()) {
 103             strippedIdentifier = YangInstanceIdentifier.create(stripShardPath(shardPath, listenerPath));
 104         }
 105
 106         final DOMDataTreeListenerWithSubshards subshardListener =
 107                 new DOMDataTreeListenerWithSubshards(strippedIdentifier, listener);
 108         final AbstractDOMDataTreeChangeListenerRegistration<L> reg =
 109                 setupContextWithoutSubshards(listenerPath, strippedIdentifier, subshardListener);
 110
 111         for (final ChildShardContext maybeAffected : childShards.values()) {
 112             if (listenerPath.contains(maybeAffected.getPrefix().getRootIdentifier())) {
 113                 // consumer has initialDataChangeEvent subshard somewhere on lower level
 114                 // register to the notification manager with snapshot and forward child notifications to parent
 115                 LOG.debug("Adding new subshard{{}} to listener at {}", maybeAffected.getPrefix(), listenerPath);
 116                 subshardListener.addSubshard(maybeAffected);
 117             } else if (maybeAffected.getPrefix().getRootIdentifier().contains(listenerPath)) {
 118                 // bind path is inside subshard
 119                 // TODO can this happen? seems like in ShardedDOMDataTree we are
 120                 // already registering to the lowest shard possible
 121                 throw new UnsupportedOperationException("Listener should be registered directly "
 122                         + "into initialDataChangeEvent subshard");
 123             }
 124         }
 125
 126         return reg;
 127     }
 128
 129     private <L extends DOMDataTreeChangeListener> AbstractDOMDataTreeChangeListenerRegistration<L>
 130             setupContextWithoutSubshards(final YangInstanceIdentifier shardLookup,
 131                                          final YangInstanceIdentifier listenerPath,
 132                                          final DOMDataTreeListenerWithSubshards listener) {
 133
 134         LOG.debug("Registering root listener full path: {}, path inside shard: {}", shardLookup, listenerPath);
 135
 136         // register in the shard tree
 137         final RegistrationTreeNode<AbstractDOMDataTreeChangeListenerRegistration<?>> node =
 138                 findNodeFor(listenerPath.getPathArguments());
 139
 140         // register listener in CDS
 141         final ProxyRegistration proxyReg = new ProxyRegistration(distributedDataStore
 142                 .registerProxyListener(shardLookup, listenerPath, listener), listener);
 143
 144         @SuppressWarnings("unchecked")
 145         final AbstractDOMDataTreeChangeListenerRegistration<L> registration =
 146             new AbstractDOMDataTreeChangeListenerRegistration<L>((L) listener) {
 147                 @Override
 148                 protected void removeRegistration() {
 149                     listener.close();
 150                     DistributedShardChangePublisher.this.removeRegistration(node, this);
 151                     registrationRemoved(this);
 152                     proxyReg.close();
 153                 }
 154             };
 155         addRegistration(node, registration);
 156
 157         return registration;
 158     }
 159
 160     private static Iterable<PathArgument> stripShardPath(final YangInstanceIdentifier shardPath,
 161                                                          final YangInstanceIdentifier listenerPath) {
 162         if (shardPath.isEmpty()) {
 163             return listenerPath.getPathArguments();
 164         }
 165
 166         final List<PathArgument> listenerPathArgs = new ArrayList<>(listenerPath.getPathArguments());
 167         final Iterator<PathArgument> shardIter = shardPath.getPathArguments().iterator();
 168         final Iterator<PathArgument> listenerIter = listenerPathArgs.iterator();
 169
 170         while (shardIter.hasNext()) {
 171             if (shardIter.next().equals(listenerIter.next())) {
 172                 listenerIter.remove();
 173             } else {
 174                 break;
 175             }
 176         }
 177
 178         return listenerPathArgs;
 179     }
 180
 181     private static final class ProxyRegistration implements ListenerRegistration<DOMDataTreeChangeListener> {
 182
 183         private final ListenerRegistration<org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener> proxy;
 184         private final DOMDataTreeChangeListener listener;
 185
 186         private ProxyRegistration(
 187                 final ListenerRegistration<
 188                         org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener> proxy,
 189                 final DOMDataTreeChangeListener listener) {
 190             this.proxy = proxy;
 191             this.listener = listener;
 192         }
 193
 194         @Override
 195         public DOMDataTreeChangeListener getInstance() {
 196             return listener;
 197         }
 198
 199         @Override
 200         public void close() {
 201             proxy.close();
 202         }
 203     }
 204
 205     synchronized DataTreeCandidate applyChanges(final YangInstanceIdentifier listenerPath,
 206             final Collection<DataTreeCandidate> changes) throws DataValidationFailedException {
 207         final DataTreeModification modification = dataTree.takeSnapshot().newModification();
 208         for (final DataTreeCandidate change : changes) {
 209             try {
 210                 DataTreeCandidates.applyToModification(modification, change);
 211             } catch (SchemaValidationFailedException e) {
 212                 LOG.error("Validation failed {}", e);
 213             }
 214         }
 215
 216         modification.ready();
 217
 218         final DataTreeCandidate candidate;
 219
 220         dataTree.validate(modification);
 221
 222         // strip nodes we dont need since this listener doesn't have to be registered at the root of the DataTree
 223         candidate = dataTree.prepare(modification);
 224         dataTree.commit(candidate);
 225
 226
 227         DataTreeCandidateNode modifiedChild = candidate.getRootNode();
 228
 229         for (final PathArgument pathArgument : listenerPath.getPathArguments()) {
 230             modifiedChild = modifiedChild.getModifiedChild(pathArgument);
 231         }
 232
 233         if (modifiedChild == null) {
 234             modifiedChild = new EmptyDataTreeCandidateNode(dataTree.getRootPath().getLastPathArgument());
 235         }
 236
 237         return DataTreeCandidates.newDataTreeCandidate(dataTree.getRootPath(), modifiedChild);
 238     }
 239
 240
 241     private final class DOMDataTreeListenerWithSubshards implements DOMDataTreeChangeListener {
 242
 243         private final YangInstanceIdentifier listenerPath;
 244         private final DOMDataTreeChangeListener delegate;
 245         private final Map<YangInstanceIdentifier, ListenerRegistration<DOMDataTreeChangeListener>> registrations =
 246                 new ConcurrentHashMap<>();
 247
 248         @GuardedBy("this")
 249         private final Collection<DataTreeCandidate> stashedDataTreeCandidates = new LinkedList<>();
 250
 251         DOMDataTreeListenerWithSubshards(final YangInstanceIdentifier listenerPath,
 252                                          final DOMDataTreeChangeListener delegate) {
 253             this.listenerPath = Preconditions.checkNotNull(listenerPath);
 254             this.delegate = Preconditions.checkNotNull(delegate);
 255         }
 256
 257         @Override
 258         public synchronized void onDataTreeChanged(@Nonnull final Collection<DataTreeCandidate> changes) {
 259             LOG.debug("Received data changed {}", changes);
 260
 261             if (!stashedDataTreeCandidates.isEmpty()) {
 262                 LOG.debug("Adding stashed subshards' changes {}", stashedDataTreeCandidates);
 263                 changes.addAll(stashedDataTreeCandidates);
 264                 stashedDataTreeCandidates.clear();
 265             }
 266
 267             try {
 268                 applyChanges(listenerPath, changes);
 269             } catch (final DataValidationFailedException e) {
 270                 // TODO should we fail here? What if stashed changes
 271                 // (changes from subshards) got ahead more than one generation
 272                 // from current shard. Than we can fail to apply this changes
 273                 // upon current data tree, but once we get respective changes
 274                 // from current shard, we can apply also changes from
 275                 // subshards.
 276                 //
 277                 // However, we can loose ability to notice and report some
 278                 // errors then. For example, we cannot detect potential lost
 279                 // changes from current shard.
 280                 LOG.error("Validation failed for modification built from changes {}, current data tree: {}",
 281                         changes, dataTree, e);
 282                 throw new RuntimeException("Notification validation failed", e);
 283             }
 284
 285             delegate.onDataTreeChanged(changes);
 286         }
 287
 288         synchronized void onDataTreeChanged(final YangInstanceIdentifier pathFromRoot,
 289                                             final Collection<DataTreeCandidate> changes) {
 290             final YangInstanceIdentifier changeId =
 291                     YangInstanceIdentifier.create(stripShardPath(dataTree.getRootPath(), pathFromRoot));
 292
 293             final List<DataTreeCandidate> newCandidates = changes.stream()
 294                     .map(candidate -> DataTreeCandidates.newDataTreeCandidate(changeId, candidate.getRootNode()))
 295                     .collect(Collectors.toList());
 296
 297             try {
 298                 delegate.onDataTreeChanged(Collections.singleton(applyChanges(listenerPath, newCandidates)));
 299             } catch (final DataValidationFailedException e) {
 300                 // We cannot apply changes from subshard to current data tree.
 301                 // Maybe changes from current shard haven't been applied to
 302                 // data tree yet. Postpone processing of these changes till we
 303                 // receive changes from current shard.
 304                 LOG.debug("Validation for modification built from subshard {} changes {} failed, current data tree {}.",
 305                         pathFromRoot, changes, dataTree, e);
 306                 stashedDataTreeCandidates.addAll(newCandidates);
 307             }
 308         }
 309
 310         void addSubshard(final ChildShardContext context) {
 311             Preconditions.checkState(context.getShard() instanceof DOMStoreTreeChangePublisher,
 312                     "All subshards that are initialDataChangeEvent part of ListenerContext need to be listenable");
 313
 314             final DOMStoreTreeChangePublisher listenableShard = (DOMStoreTreeChangePublisher) context.getShard();
 315             // since this is going into subshard we want to listen for ALL changes in the subshard
 316             registrations.put(context.getPrefix().getRootIdentifier(),
 317                     listenableShard.registerTreeChangeListener(
 318                             context.getPrefix().getRootIdentifier(), changes -> onDataTreeChanged(
 319                                     context.getPrefix().getRootIdentifier(), changes)));
 320         }
 321
 322         void close() {
 323             for (final ListenerRegistration<DOMDataTreeChangeListener> registration : registrations.values()) {
 324                 registration.close();
 325             }
 326             registrations.clear();
 327         }
 328     }
 329
 330     private static final class EmptyDataTreeCandidateNode implements DataTreeCandidateNode {
 331
 332         private final PathArgument identifier;
 333
 334         EmptyDataTreeCandidateNode(final PathArgument identifier) {
 335             this.identifier = Preconditions.checkNotNull(identifier, "Identifier should not be null");
 336         }
 337
 338         @Nonnull
 339         @Override
 340         public PathArgument getIdentifier() {
 341             return identifier;
 342         }
 343
 344         @Nonnull
 345         @Override
 346         public Collection<DataTreeCandidateNode> getChildNodes() {
 347             return Collections.emptySet();
 348         }
 349
 350         @Nullable
 351         @Override
 352         @SuppressWarnings("checkstyle:hiddenField")
 353         public DataTreeCandidateNode getModifiedChild(final PathArgument identifier) {
 354             return null;
 355         }
 356
 357         @Nonnull
 358         @Override
 359         public ModificationType getModificationType() {
 360             return ModificationType.UNMODIFIED;
 361         }
 362
 363         @Nonnull
 364         @Override
 365         public Optional<NormalizedNode<?, ?>> getDataAfter() {
 366             return Optional.absent();
 367         }
 368
 369         @Nonnull
 370         @Override
 371         public Optional<NormalizedNode<?, ?>> getDataBefore() {
 372             return Optional.absent();
 373         }
 374     }
 375 }