singleton-service/mdsal-singleton-dom-impl/src/main/java/org/opendaylight/mdsal/singleton/dom/impl/ClusterSingletonServiceGroupImpl.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 com.google.common.annotations.VisibleForTesting;
  12 import com.google.common.base.Preconditions;
  13 import com.google.common.base.Strings;
  14 import com.google.common.base.Verify;
  15 import com.google.common.util.concurrent.FutureCallback;
  16 import com.google.common.util.concurrent.Futures;
  17 import com.google.common.util.concurrent.ListenableFuture;
  18 import java.util.ArrayList;
  19 import java.util.LinkedList;
  20 import java.util.List;
  21 import java.util.concurrent.ConcurrentMap;
  22 import java.util.concurrent.Semaphore;
  23 import java.util.concurrent.TimeUnit;
  24 import java.util.function.Consumer;
  25 import javax.annotation.Nullable;
  26 import javax.annotation.concurrent.GuardedBy;
  27 import org.opendaylight.mdsal.eos.common.api.EntityOwnershipChangeState;
  28 import org.opendaylight.mdsal.eos.common.api.GenericEntity;
  29 import org.opendaylight.mdsal.eos.common.api.GenericEntityOwnershipCandidateRegistration;
  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.GenericEntityOwnershipService;
  33 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonService;
  34 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonServiceRegistration;
  35 import org.opendaylight.yangtools.concepts.Path;
  36 import org.slf4j.Logger;
  37 import org.slf4j.LoggerFactory;
  38
  39 /**
  40  * Implementation of {@link ClusterSingletonServiceGroup}.
  41  *
  42  * @param <P> the instance identifier path type
  43  * @param <E> the GenericEntity type
  44  * @param <C> the GenericEntityOwnershipChange type
  45  * @param <G> the GenericEntityOwnershipListener type
  46  * @param <S> the GenericEntityOwnershipService type
  47  */
  48 @VisibleForTesting
  49 final class ClusterSingletonServiceGroupImpl<P extends Path<P>, E extends GenericEntity<P>,
  50                                              C extends GenericEntityOwnershipChange<P, E>,
  51                                              G extends GenericEntityOwnershipListener<P, C>,
  52                                              S extends GenericEntityOwnershipService<P, E, G>>
  53         implements ClusterSingletonServiceGroup<P, E, C> {
  54
  55     private static final Logger LOG = LoggerFactory.getLogger(ClusterSingletonServiceGroupImpl.class.getName());
  56
  57     private final S entityOwnershipService;
  58     private final String clusterSingletonGroupIdentifier;
  59     private final Semaphore clusterLock = new Semaphore(1, true);
  60
  61     /* Entity instances */
  62     private final E serviceEntity;
  63     private final E doubleCandidateEntity;
  64
  65     // TODO :it needs to rewrite for StateMachine (INITIALIZED, TRY_TO_TAKE_LEADERSHIP, LEADER, FOLLOWER, TERMINATED)
  66     // INITIALIZED : we have registered baseCandidate and we are waiting for first EOS response (!do we really need it?)
  67     // FOLLOWER : baseCandidate is registered correctly
  68     // TRY_TO_TAKE_LEADERSHIP : guardCandidate is registered correctly
  69     // LEADER : both candidate have mastership from EOS
  70     // TERMINATED : service go down
  71     @GuardedBy("clusterLock")
  72     private boolean hasOwnership = false;
  73     @GuardedBy("clusterLock")
  74     private final List<ClusterSingletonServiceRegistrationDelegator> serviceGroup = new LinkedList<>();
  75     private final ConcurrentMap<String, ClusterSingletonServiceGroup<P, E, C>> allServiceGroups;
  76
  77     /* EOS Candidate Registrations */
  78     private GenericEntityOwnershipCandidateRegistration<P, E> serviceEntityCandidateReg;
  79     private GenericEntityOwnershipCandidateRegistration<P, E> asyncCloseEntityCandidateReg;
  80
  81     /**
  82      * Class constructor.
  83      *
  84      * @param clusterSingletonServiceGroupIdentifier not empty string as identifier
  85      * @param mainEntity as Entity instance
  86      * @param closeEntity as Entity instance
  87      * @param entityOwnershipService GenericEntityOwnershipService instance
  88      * @param allServiceGroups concurrentMap of String and ClusterSingletonServiceGroup type
  89      */
  90     ClusterSingletonServiceGroupImpl(final String clusterSingletonServiceGroupIdentifier, final E mainEntity,
  91             final E closeEntity, final S entityOwnershipService,
  92             final ConcurrentMap<String, ClusterSingletonServiceGroup<P, E, C>> allServiceGroups) {
  93         LOG.debug("New Instance of ClusterSingletonServiceGroup {}", clusterSingletonServiceGroupIdentifier);
  94         Preconditions.checkArgument(!Strings.isNullOrEmpty(clusterSingletonServiceGroupIdentifier));
  95         this.clusterSingletonGroupIdentifier = clusterSingletonServiceGroupIdentifier;
  96         this.entityOwnershipService = Preconditions.checkNotNull(entityOwnershipService);
  97         this.serviceEntity = Preconditions.checkNotNull(mainEntity);
  98         this.doubleCandidateEntity = Preconditions.checkNotNull(closeEntity);
  99         this.allServiceGroups = Preconditions.checkNotNull(allServiceGroups);
 100     }
 101
 102     @SuppressWarnings("checkstyle:IllegalCatch")
 103     @Override
 104     public ListenableFuture<List<Void>> closeClusterSingletonGroup() {
 105         LOG.debug("Close method for service Provider {}", clusterSingletonGroupIdentifier);
 106         boolean needReleaseLock = false;
 107         final ListenableFuture<List<Void>> destroyFuture;
 108         try {
 109             needReleaseLock = clusterLock.tryAcquire(1, TimeUnit.SECONDS);
 110         } catch (final Exception e) {
 111             LOG.warn("Unexpected Exception for service Provider {} in closing phase.", clusterSingletonGroupIdentifier,
 112                     e);
 113         } finally {
 114             if (serviceEntityCandidateReg != null) {
 115                 serviceEntityCandidateReg.close();
 116                 serviceEntityCandidateReg = null;
 117             }
 118             final List<ListenableFuture<Void>> serviceCloseFutureList = new ArrayList<>();
 119             if (hasOwnership) {
 120                 for (final ClusterSingletonServiceRegistrationDelegator service : serviceGroup) {
 121                     serviceCloseFutureList.add(service.closeServiceInstance());
 122                 }
 123                 hasOwnership = false;
 124             }
 125             destroyFuture = Futures.allAsList(serviceCloseFutureList);
 126             final Semaphore finalRelease = needReleaseLock ? clusterLock : null;
 127             Futures.addCallback(destroyFuture, newAsyncCloseCallback(finalRelease, true));
 128         }
 129         return destroyFuture;
 130     }
 131
 132     @SuppressWarnings("checkstyle:IllegalCatch")
 133     @Override
 134     public void initializationClusterSingletonGroup() {
 135         LOG.debug("Initialization ClusterSingletonGroup {}", clusterSingletonGroupIdentifier);
 136         boolean needReleaseLock = false;
 137         boolean needCloseProviderInstance = false;
 138         try {
 139             clusterLock.acquire();
 140             needReleaseLock = true;
 141             Verify.verify(serviceGroup.isEmpty());
 142             Verify.verify(!hasOwnership);
 143             Verify.verify(serviceEntityCandidateReg == null);
 144             serviceEntityCandidateReg = entityOwnershipService.registerCandidate(serviceEntity);
 145         } catch (final Exception e) {
 146             LOG.debug("Unexpected error by registration service Provider {}", clusterSingletonGroupIdentifier, e);
 147             needCloseProviderInstance = true;
 148             throw new RuntimeException(e);
 149         } finally {
 150             closeResources(needReleaseLock, needCloseProviderInstance);
 151         }
 152     }
 153
 154     @SuppressWarnings("checkstyle:IllegalCatch")
 155     @Override
 156     public ClusterSingletonServiceRegistration registerService(final ClusterSingletonService service) {
 157         LOG.debug("RegisterService method call for ClusterSingletonServiceGroup {}", clusterSingletonGroupIdentifier);
 158         Verify.verify(clusterSingletonGroupIdentifier.equals(service.getIdentifier().getValue()));
 159         boolean needReleaseLock = false;
 160         boolean needCloseProviderInstance = false;
 161         ClusterSingletonServiceRegistrationDelegator reg = null;
 162         try {
 163             clusterLock.acquire();
 164             needReleaseLock = true;
 165             Verify.verify(serviceEntityCandidateReg != null);
 166             reg = new ClusterSingletonServiceRegistrationDelegator(service, this);
 167             serviceGroup.add(reg);
 168             if (hasOwnership) {
 169                 service.instantiateServiceInstance();
 170             }
 171         } catch (final Exception e) {
 172             LOG.debug("Unexpected error by registration service Provider {}", clusterSingletonGroupIdentifier, e);
 173             needCloseProviderInstance = true;
 174             throw new RuntimeException(e);
 175         } finally {
 176             closeResources(needReleaseLock, needCloseProviderInstance);
 177         }
 178         return reg;
 179     }
 180
 181     @SuppressWarnings("checkstyle:IllegalCatch")
 182     @Override
 183     public void unregisterService(final ClusterSingletonService service) {
 184         LOG.debug("UnregisterService method call for ClusterSingletonServiceGroup {}", clusterSingletonGroupIdentifier);
 185         Verify.verify(clusterSingletonGroupIdentifier.equals(service.getIdentifier().getValue()));
 186         boolean needReleaseLock = false;
 187         boolean needCloseProviderInstance = false;
 188         try {
 189             clusterLock.acquire();
 190             needReleaseLock = true;
 191             if (serviceGroup.size() > 1) {
 192                 if (hasOwnership) {
 193                     service.closeServiceInstance();
 194                 }
 195                 serviceGroup.remove(service);
 196                 LOG.debug("Service {} was removed from group.", service.getIdentifier().getValue());
 197             } else {
 198                 needCloseProviderInstance = true;
 199             }
 200         } catch (final Exception e) {
 201             LOG.debug("Unexpected error by registration service Provider {}", clusterSingletonGroupIdentifier, e);
 202             needCloseProviderInstance = true;
 203             throw new RuntimeException(e);
 204         } finally {
 205             closeResources(needReleaseLock, needCloseProviderInstance);
 206         }
 207     }
 208
 209     @SuppressWarnings("checkstyle:IllegalCatch")
 210     @Override
 211     public void ownershipChanged(final C ownershipChange) {
 212         LOG.debug("Ownership change {} for ClusterSingletonServiceGroup {}", ownershipChange,
 213                 clusterSingletonGroupIdentifier);
 214         try {
 215             if (ownershipChange.inJeopardy()) {
 216                 LOG.warn("Cluster Node lost connection to another cluster nodes {}", ownershipChange);
 217                 lostOwnership();
 218                 return;
 219             }
 220             if (serviceEntity.equals(ownershipChange.getEntity())) {
 221                 if (EntityOwnershipChangeState.LOCAL_OWNERSHIP_GRANTED.equals(ownershipChange.getState())) {
 222                     /*
 223                      * SLAVE to MASTER : ownershipChange.getState().isOwner() && !ownershipChange.getState().wasOwner()
 224                      */
 225                     tryToTakeOwnership();
 226                 } else if (EntityOwnershipChangeState.LOCAL_OWNERSHIP_LOST_NEW_OWNER.equals(ownershipChange.getState())
 227                         || EntityOwnershipChangeState.LOCAL_OWNERSHIP_LOST_NO_OWNER
 228                                 .equals(ownershipChange.getState())) {
 229                     /*
 230                      * MASTER to SLAVE : !ownershipChange.getState().isOwner() && ownershipChange.getState().wasOwner()
 231                      */
 232                     lostOwnership();
 233                 } else {
 234                     /* Not needed notifications */
 235                     LOG.debug("Not processed entity OwnershipChange {} in service Provider {}", ownershipChange,
 236                             clusterSingletonGroupIdentifier);
 237                 }
 238             } else if (doubleCandidateEntity.equals(ownershipChange.getEntity())) {
 239                 if (EntityOwnershipChangeState.LOCAL_OWNERSHIP_GRANTED.equals(ownershipChange.getState())) {
 240                     /*
 241                      * SLAVE to MASTER : ownershipChange.getState().isOwner() && !ownershipChange.getState().wasOwner()
 242                      */
 243                     takeOwnership();
 244                 } else {
 245                     /* Not needed notifications */
 246                     LOG.debug("Not processed doubleCandidate OwnershipChange {} in service Provider {}",
 247                             ownershipChange, clusterSingletonGroupIdentifier);
 248                 }
 249             } else {
 250                 LOG.warn("Unexpected EntityOwnershipChangeEvent for entity {}", ownershipChange);
 251             }
 252         } catch (final Exception e) {
 253             LOG.error("Unexpected Exception for service Provider {}", clusterSingletonGroupIdentifier, e);
 254             // TODO : think about close ... is it necessary?
 255         }
 256     }
 257
 258     /*
 259      * Help method to registered DoubleCandidateEntity. It is first step
 260      * before the actual instance take Leadership.
 261      */
 262     @SuppressWarnings("checkstyle:IllegalCatch")
 263     private void tryToTakeOwnership() {
 264         LOG.debug("TryToTakeLeadership method for service Provider {}", clusterSingletonGroupIdentifier);
 265         boolean needReleaseLock = false;
 266         boolean needCloseProviderInstance = false;
 267         try {
 268             clusterLock.acquire();
 269             needReleaseLock = true;
 270             if (serviceEntityCandidateReg != null) {
 271                 Verify.verify(asyncCloseEntityCandidateReg == null);
 272                 asyncCloseEntityCandidateReg = entityOwnershipService.registerCandidate(doubleCandidateEntity);
 273             } else {
 274                 LOG.debug("Service {} is closed, so don't to tryTakeLeadership", clusterSingletonGroupIdentifier);
 275             }
 276         } catch (final Exception e) {
 277             LOG.error("Unexpected exception state for service Provider {} in TryToTakeLeadership",
 278                     clusterSingletonGroupIdentifier, e);
 279             needCloseProviderInstance = true;
 280         } finally {
 281             closeResources(needReleaseLock, needCloseProviderInstance);
 282         }
 283     }
 284
 285     /*
 286      * Help method calls setupService method for create single cluster-wide service instance.
 287      */
 288     @SuppressWarnings("checkstyle:IllegalCatch")
 289     private void takeOwnership() {
 290         LOG.debug("TakeLeadership method for service Provider {}", clusterSingletonGroupIdentifier);
 291         boolean needReleaseLock = false;
 292         boolean needCloseProviderInstance = false;
 293         try {
 294             clusterLock.acquire();
 295             needReleaseLock = true;
 296             if (serviceEntityCandidateReg != null) {
 297                 Verify.verify(asyncCloseEntityCandidateReg != null);
 298                 for (final ClusterSingletonServiceRegistrationDelegator service : serviceGroup) {
 299                     service.instantiateServiceInstance();
 300                 }
 301                 hasOwnership = true;
 302             } else {
 303                 LOG.debug("Service {} is closed, so don't take leadership", clusterSingletonGroupIdentifier);
 304             }
 305         } catch (final Exception e) {
 306             LOG.error("Unexpected exception state for service Provider {} in TakeLeadership",
 307                     clusterSingletonGroupIdentifier, e);
 308             needCloseProviderInstance = true;
 309         } finally {
 310             closeResources(needReleaseLock, needCloseProviderInstance);
 311         }
 312     }
 313
 314     /*
 315      * Help method calls suspendService method for stop this single cluster-wide service instance.
 316      * The last async. step has to close DoubleCandidateRegistration reference what should initialize
 317      * new election for DoubleCandidateEntity.
 318      */
 319     @SuppressWarnings("checkstyle:IllegalCatch")
 320     private void lostOwnership() {
 321         LOG.debug("LostLeadership method for service Provider {}", clusterSingletonGroupIdentifier);
 322         boolean needReleaseLock = false;
 323         boolean needCloseProviderInstance = false;
 324         try {
 325             clusterLock.acquire();
 326             needReleaseLock = true;
 327             final List<ListenableFuture<Void>> serviceCloseFutureList = new ArrayList<>();
 328             if (hasOwnership) {
 329                 Verify.verify(asyncCloseEntityCandidateReg != null);
 330                 for (final ClusterSingletonServiceRegistrationDelegator service : serviceGroup) {
 331                     serviceCloseFutureList.add(service.closeServiceInstance());
 332                 }
 333                 hasOwnership = false;
 334             }
 335
 336             final ListenableFuture<List<Void>> destroyFuture = Futures.allAsList(serviceCloseFutureList);
 337             if (serviceEntityCandidateReg != null) {
 338                 // we don't want to remove this instance from map
 339                 Futures.addCallback(destroyFuture, newAsyncCloseCallback(clusterLock, false));
 340             } else {
 341                 // we have to remove this ClusterSingletonServiceGroup instance from map
 342                 Futures.addCallback(destroyFuture, newAsyncCloseCallback(clusterLock, true));
 343             }
 344             /*
 345              * We wish to stop all possible EOS activities before we don't close
 346              * a close candidate registration that acts as a guard. So we don't want
 347              * to release Semaphore (clusterLock) before we are not fully finished.
 348              * Semaphore lock release has to be realized as FutureCallback after a service
 349              * instance has fully closed prior to relinquishing service ownership.
 350              */
 351             needReleaseLock = false;
 352         } catch (final Exception e) {
 353             LOG.error("Unexpected exception state for service Provider {} in LostLeadership",
 354                     clusterSingletonGroupIdentifier, e);
 355             needCloseProviderInstance = true;
 356         } finally {
 357             closeResources(needReleaseLock, needCloseProviderInstance);
 358         }
 359     }
 360
 361     /*
 362      * Help method for finalization every acquired functionality
 363      */
 364     @GuardedBy("clusterLock")
 365     private void closeResources(final boolean needReleaseLock, final boolean needCloseProvider) {
 366         if (needCloseProvider) {
 367             // The Game Over for this ClusterSingletonServiceGroup instance
 368             if (serviceEntityCandidateReg != null) {
 369                 serviceEntityCandidateReg.close();
 370                 serviceEntityCandidateReg = null;
 371             }
 372             // Remove instance immediately because actual state is follower or initialization
 373             if (asyncCloseEntityCandidateReg == null) {
 374                 allServiceGroups.remove(clusterSingletonGroupIdentifier, this);
 375             }
 376         }
 377
 378         if (needReleaseLock) {
 379             clusterLock.release();
 380         }
 381     }
 382
 383     /*
 384      * Help method creates FutureCallback for suspend Future
 385      */
 386     private FutureCallback<List<Void>> newAsyncCloseCallback(@Nullable final Semaphore semaphore,
 387             final boolean isInCloseProcess) {
 388         final Consumer<Throwable> closeEntityCandidateRegistration = (@Nullable final Throwable throwable) -> {
 389             if (throwable != null) {
 390                 LOG.warn("Unexpected error closing service instance {}", clusterSingletonGroupIdentifier, throwable);
 391             } else {
 392                 LOG.debug("Destroy service Instance {} is success", clusterSingletonGroupIdentifier);
 393             }
 394             if (asyncCloseEntityCandidateReg != null) {
 395                 asyncCloseEntityCandidateReg.close();
 396                 asyncCloseEntityCandidateReg = null;
 397             }
 398             if (isInCloseProcess) {
 399                 allServiceGroups.remove(clusterSingletonGroupIdentifier, this);
 400             }
 401             if (semaphore != null) {
 402                 semaphore.release();
 403             }
 404         };
 405
 406         return new FutureCallback<List<Void>>() {
 407
 408             @Override
 409             public void onSuccess(final List<Void> result) {
 410                 closeEntityCandidateRegistration.accept(null);
 411             }
 412
 413             @Override
 414             public void onFailure(final Throwable throwable) {
 415                 closeEntityCandidateRegistration.accept(throwable);
 416             }
 417         };
 418     }
 419
 420 }