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