singleton-service/mdsal-singleton-dom-impl/src/main/java/org/opendaylight/mdsal/singleton/dom/impl/AbstractClusterSingletonServiceProviderImpl.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.mdsal.singleton.dom.impl;
  10
  11 import static com.google.common.base.Verify.verify;
  12 import static com.google.common.base.Verify.verifyNotNull;
  13
  14 import com.google.common.annotations.VisibleForTesting;
  15 import com.google.common.base.Preconditions;
  16 import com.google.common.base.Strings;
  17 import com.google.common.base.Verify;
  18 import com.google.common.util.concurrent.FutureCallback;
  19 import com.google.common.util.concurrent.Futures;
  20 import com.google.common.util.concurrent.ListenableFuture;
  21 import com.google.common.util.concurrent.MoreExecutors;
  22 import java.util.ArrayList;
  23 import java.util.List;
  24 import java.util.Map;
  25 import java.util.concurrent.ConcurrentHashMap;
  26 import javax.annotation.CheckForNull;
  27 import javax.annotation.Nonnull;
  28 import org.opendaylight.mdsal.eos.common.api.CandidateAlreadyRegisteredException;
  29 import org.opendaylight.mdsal.eos.common.api.GenericEntity;
  30 import org.opendaylight.mdsal.eos.common.api.GenericEntityOwnershipChange;
  31 import org.opendaylight.mdsal.eos.common.api.GenericEntityOwnershipListener;
  32 import org.opendaylight.mdsal.eos.common.api.GenericEntityOwnershipListenerRegistration;
  33 import org.opendaylight.mdsal.eos.common.api.GenericEntityOwnershipService;
  34 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonService;
  35 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonServiceProvider;
  36 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonServiceRegistration;
  37 import org.opendaylight.yangtools.concepts.Path;
  38 import org.slf4j.Logger;
  39 import org.slf4j.LoggerFactory;
  40
  41 /**
  42  * Abstract class {@link AbstractClusterSingletonServiceProviderImpl} represents implementations of
  43  * {@link ClusterSingletonServiceProvider} and it implements {@link GenericEntityOwnershipListener}
  44  * for providing OwnershipChange for all registered {@link ClusterSingletonServiceGroup} entity
  45  * candidate.
  46  *
  47  * @param <P> the instance identifier path type
  48  * @param <E> the GenericEntity type
  49  * @param <C> the GenericEntityOwnershipChange type
  50  * @param <G> the GenericEntityOwnershipListener type
  51  * @param <S> the GenericEntityOwnershipService type
  52  * @param <R> the GenericEntityOwnershipListenerRegistration type
  53  */
  54 public abstract class AbstractClusterSingletonServiceProviderImpl<P extends Path<P>, E extends GenericEntity<P>,
  55         C extends GenericEntityOwnershipChange<P, E>,
  56         G extends GenericEntityOwnershipListener<P, C>,
  57         S extends GenericEntityOwnershipService<P, E, G>,
  58         R extends GenericEntityOwnershipListenerRegistration<P, G>>
  59         implements ClusterSingletonServiceProvider, GenericEntityOwnershipListener<P, C> {
  60
  61     private static final Logger LOG = LoggerFactory.getLogger(AbstractClusterSingletonServiceProviderImpl.class);
  62
  63     @VisibleForTesting
  64     static final String SERVICE_ENTITY_TYPE = "org.opendaylight.mdsal.ServiceEntityType";
  65     @VisibleForTesting
  66     static final String CLOSE_SERVICE_ENTITY_TYPE = "org.opendaylight.mdsal.AsyncServiceCloseEntityType";
  67
  68     private final S entityOwnershipService;
  69     private final Map<String, ClusterSingletonServiceGroup<P, E, C>> serviceGroupMap = new ConcurrentHashMap<>();
  70
  71     /* EOS Entity Listeners Registration */
  72     private R serviceEntityListenerReg;
  73     private R asyncCloseEntityListenerReg;
  74
  75     /**
  76      * Class constructor.
  77      *
  78      * @param entityOwnershipService relevant EOS
  79      */
  80     protected AbstractClusterSingletonServiceProviderImpl(@Nonnull final S entityOwnershipService) {
  81         this.entityOwnershipService = Preconditions.checkNotNull(entityOwnershipService);
  82     }
  83
  84     /**
  85      * This method must be called once on startup to initialize this provider.
  86      */
  87     public final void initializeProvider() {
  88         LOG.debug("Initialization method for ClusterSingletonService Provider {}", this);
  89         this.serviceEntityListenerReg = registerListener(SERVICE_ENTITY_TYPE, entityOwnershipService);
  90         this.asyncCloseEntityListenerReg = registerListener(CLOSE_SERVICE_ENTITY_TYPE, entityOwnershipService);
  91     }
  92
  93     @Override
  94     public final synchronized ClusterSingletonServiceRegistration registerClusterSingletonService(
  95             @CheckForNull final ClusterSingletonService service) {
  96         LOG.debug("Call registrationService {} method for ClusterSingletonService Provider {}", service, this);
  97
  98         final String serviceIdentifier = service.getIdentifier().getValue();
  99         Preconditions.checkArgument(!Strings.isNullOrEmpty(serviceIdentifier),
 100                 "ClusterSingletonService identifier may not be null nor empty");
 101
 102         final ClusterSingletonServiceGroup<P, E, C> serviceGroup;
 103         ClusterSingletonServiceGroup<P, E, C> existing = serviceGroupMap.get(serviceIdentifier);
 104         if (existing == null) {
 105             serviceGroup = createGroup(serviceIdentifier, new ArrayList<>(1));
 106             serviceGroupMap.put(serviceIdentifier, serviceGroup);
 107
 108             try {
 109                 initializeOrRemoveGroup(serviceGroup);
 110             } catch (CandidateAlreadyRegisteredException e) {
 111                 throw new IllegalArgumentException("Service group already registered", e);
 112             }
 113         } else {
 114             serviceGroup = existing;
 115         }
 116
 117         serviceGroup.registerService(service);
 118         return new AbstractClusterSingletonServiceRegistration(service) {
 119             @Override
 120             protected void removeRegistration() {
 121                 // We need to bounce the unregistration through a ordered lock in order not to deal with asynchronous
 122                 // shutdown of the group and user registering it again.
 123                 AbstractClusterSingletonServiceProviderImpl.this.removeRegistration(serviceIdentifier, service);
 124             }
 125         };
 126     }
 127
 128     private ClusterSingletonServiceGroup<P, E, C> createGroup(final String serviceIdentifier,
 129             final List<ClusterSingletonService> services) {
 130         return new ClusterSingletonServiceGroupImpl<>(serviceIdentifier, entityOwnershipService,
 131                 createEntity(SERVICE_ENTITY_TYPE, serviceIdentifier),
 132                 createEntity(CLOSE_SERVICE_ENTITY_TYPE, serviceIdentifier), services);
 133     }
 134
 135     private void initializeOrRemoveGroup(final ClusterSingletonServiceGroup<P, E, C> group)
 136             throws CandidateAlreadyRegisteredException {
 137         try {
 138             group.initialize();
 139         } catch (CandidateAlreadyRegisteredException e) {
 140             serviceGroupMap.remove(group.getIdentifier(), group);
 141             throw e;
 142         }
 143     }
 144
 145     void removeRegistration(final String serviceIdentifier, final ClusterSingletonService service) {
 146
 147         final PlaceholderGroup<P, E, C> placeHolder;
 148         final ListenableFuture<?> future;
 149         synchronized (this) {
 150             final ClusterSingletonServiceGroup<P, E, C> lookup = verifyNotNull(serviceGroupMap.get(serviceIdentifier));
 151             if (!lookup.unregisterService(service)) {
 152                 return;
 153             }
 154
 155             // Close the group and replace it with a placeholder
 156             LOG.debug("Closing service group {}", serviceIdentifier);
 157             future = lookup.closeClusterSingletonGroup();
 158             placeHolder = new PlaceholderGroup<>(lookup, future);
 159
 160             final String identifier = service.getIdentifier().getValue();
 161             verify(serviceGroupMap.replace(identifier, lookup, placeHolder));
 162             LOG.debug("Replaced group {} with {}", serviceIdentifier, placeHolder);
 163         }
 164
 165         future.addListener(() -> finishShutdown(placeHolder), MoreExecutors.directExecutor());
 166     }
 167
 168     synchronized void finishShutdown(final PlaceholderGroup<P, E, C> placeHolder) {
 169         final String identifier = placeHolder.getIdentifier();
 170         LOG.debug("Service group {} closed", identifier);
 171
 172         final List<ClusterSingletonService> services = placeHolder.getServices();
 173         if (services.isEmpty()) {
 174             // No services, we are all done
 175             if (serviceGroupMap.remove(identifier, placeHolder)) {
 176                 LOG.debug("Service group {} removed", placeHolder);
 177             } else {
 178                 LOG.debug("Service group {} superseded by {}", placeHolder, serviceGroupMap.get(identifier));
 179             }
 180             return;
 181         }
 182
 183         // Placeholder is being retired, we are reusing its services as the seed for the group.
 184         final ClusterSingletonServiceGroup<P, E, C> group = createGroup(identifier, services);
 185         Verify.verify(serviceGroupMap.replace(identifier, placeHolder, group));
 186         placeHolder.setSuccessor(group);
 187         LOG.debug("Service group upgraded from {} to {}", placeHolder, group);
 188
 189         try {
 190             initializeOrRemoveGroup(group);
 191         } catch (CandidateAlreadyRegisteredException e) {
 192             LOG.error("Failed to register delayed group {}, it will remain inoperational", identifier, e);
 193         }
 194     }
 195
 196     @Override
 197     public final void close() {
 198         LOG.debug("Close method for ClusterSingletonService Provider {}", this);
 199
 200         if (serviceEntityListenerReg != null) {
 201             serviceEntityListenerReg.close();
 202             serviceEntityListenerReg = null;
 203         }
 204
 205         final List<ListenableFuture<?>> listGroupCloseListFuture = new ArrayList<>();
 206
 207         for (final ClusterSingletonServiceGroup<P, E, C> serviceGroup : serviceGroupMap.values()) {
 208             listGroupCloseListFuture.add(serviceGroup.closeClusterSingletonGroup());
 209         }
 210
 211         final ListenableFuture<List<Object>> finalCloseFuture = Futures.allAsList(listGroupCloseListFuture);
 212         Futures.addCallback(finalCloseFuture, new FutureCallback<List<?>>() {
 213
 214             @Override
 215             public void onSuccess(final List<?> result) {
 216                 cleanup();
 217             }
 218
 219             @Override
 220             public void onFailure(final Throwable throwable) {
 221                 LOG.warn("Unexpected problem by closing ClusterSingletonServiceProvider {}",
 222                     AbstractClusterSingletonServiceProviderImpl.this, throwable);
 223                 cleanup();
 224             }
 225         }, MoreExecutors.directExecutor());
 226     }
 227
 228     @Override
 229     public final void ownershipChanged(final C ownershipChange) {
 230         LOG.debug("Ownership change for ClusterSingletonService Provider {}", ownershipChange);
 231         final String serviceIdentifier = getServiceIdentifierFromEntity(ownershipChange.getEntity());
 232         final ClusterSingletonServiceGroup<P, E, C> serviceHolder = serviceGroupMap.get(serviceIdentifier);
 233         if (serviceHolder != null) {
 234             serviceHolder.ownershipChanged(ownershipChange);
 235         } else {
 236             LOG.debug("ClusterSingletonServiceGroup was not found for serviceIdentifier {}", serviceIdentifier);
 237         }
 238     }
 239
 240     /**
 241      * Method implementation registers a defined {@link GenericEntityOwnershipListenerRegistration} type
 242      * EntityOwnershipListenerRegistration.
 243      *
 244      * @param entityType the type of the entity
 245      * @param entityOwnershipServiceInst - EOS type
 246      * @return instance of EntityOwnershipListenerRegistration
 247      */
 248     protected abstract R registerListener(String entityType, S entityOwnershipServiceInst);
 249
 250     /**
 251      * Creates an extended {@link GenericEntity} instance.
 252      *
 253      * @param entityType the type of the entity
 254      * @param entityIdentifier the identifier of the entity
 255      * @return instance of Entity extended GenericEntity type
 256      */
 257     protected abstract E createEntity(String entityType, String entityIdentifier);
 258
 259     /**
 260      * Method is responsible for parsing ServiceGroupIdentifier from E entity.
 261      *
 262      * @param entity instance of GenericEntity type
 263      * @return ServiceGroupIdentifier parsed from entity key value.
 264      */
 265     protected abstract String getServiceIdentifierFromEntity(E entity);
 266
 267     /**
 268      * Method is called async. from close method in end of Provider lifecycle.
 269      */
 270     final void cleanup() {
 271         LOG.debug("Final cleaning ClusterSingletonServiceProvider {}", this);
 272         if (asyncCloseEntityListenerReg != null) {
 273             asyncCloseEntityListenerReg.close();
 274             asyncCloseEntityListenerReg = null;
 275         }
 276         serviceGroupMap.clear();
 277     }
 278 }