| package org.onlab.onos.store.service.impl; |
| |
| import static org.slf4j.LoggerFactory.getLogger; |
| |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.concurrent.CompletableFuture; |
| |
| import org.apache.felix.scr.annotations.Activate; |
| import org.apache.felix.scr.annotations.Component; |
| import org.apache.felix.scr.annotations.Deactivate; |
| import org.apache.felix.scr.annotations.Reference; |
| import org.apache.felix.scr.annotations.ReferenceCardinality; |
| import org.apache.felix.scr.annotations.Service; |
| import org.joda.time.DateTime; |
| import org.onlab.onos.cluster.ClusterService; |
| import org.onlab.onos.store.cluster.messaging.ClusterCommunicationService; |
| import org.onlab.onos.store.cluster.messaging.ClusterMessage; |
| import org.onlab.onos.store.cluster.messaging.ClusterMessageHandler; |
| import org.onlab.onos.store.service.DatabaseService; |
| import org.onlab.onos.store.service.Lock; |
| import org.onlab.onos.store.service.LockEventListener; |
| import org.onlab.onos.store.service.LockService; |
| import org.slf4j.Logger; |
| |
| import com.google.common.collect.ArrayListMultimap; |
| |
| @Component(immediate = true) |
| @Service |
| public class DistributedLockManager implements LockService { |
| |
| private final Logger log = getLogger(getClass()); |
| |
| public static final String ONOS_LOCK_TABLE_NAME = "onos-locks"; |
| |
| private final ArrayListMultimap<String, LockRequest> locksToAcquire = ArrayListMultimap |
| .create(); |
| |
| @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| private ClusterCommunicationService clusterCommunicator; |
| |
| @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| private DatabaseService databaseService; |
| |
| @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| private ClusterService clusterService; |
| |
| @Activate |
| public void activate() { |
| clusterCommunicator.addSubscriber( |
| DatabaseStateMachine.DATABASE_UPDATE_EVENTS, |
| new LockEventMessageListener()); |
| log.info("Started."); |
| |
| } |
| |
| @Deactivate |
| public void deactivate() { |
| locksToAcquire.clear(); |
| log.info("Started."); |
| } |
| |
| @Override |
| public Lock create(String path) { |
| return new DistributedLock(path, databaseService, clusterService, this); |
| } |
| |
| @Override |
| public void addListener(LockEventListener listener) { |
| // FIXME: |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public void removeListener(LockEventListener listener) { |
| // FIXME: |
| throw new UnsupportedOperationException(); |
| } |
| |
| protected CompletableFuture<Void> lockIfAvailable(Lock lock, |
| long waitTimeMillis, int leaseDurationMillis) { |
| CompletableFuture<Void> future = new CompletableFuture<>(); |
| locksToAcquire.put(lock.path(), new LockRequest(lock, waitTimeMillis, |
| leaseDurationMillis, future)); |
| return future; |
| } |
| |
| private class LockEventMessageListener implements ClusterMessageHandler { |
| @Override |
| public void handle(ClusterMessage message) { |
| TableModificationEvent event = DatabaseStateMachine.SERIALIZER |
| .decode(message.payload()); |
| if (!event.tableName().equals(ONOS_LOCK_TABLE_NAME)) { |
| return; |
| } |
| |
| log.info("Received a lock available event for path: {}", event.key()); |
| |
| String path = event.key(); |
| if (!locksToAcquire.containsKey(path)) { |
| return; |
| } |
| |
| if (event.type() == TableModificationEvent.Type.ROW_DELETED) { |
| List<LockRequest> existingRequests = locksToAcquire.get(path); |
| if (existingRequests == null) { |
| return; |
| } |
| |
| synchronized (existingRequests) { |
| |
| Iterator<LockRequest> existingRequestIterator = existingRequests |
| .iterator(); |
| while (existingRequestIterator.hasNext()) { |
| LockRequest request = existingRequestIterator.next(); |
| if (request.expirationTime().isAfter(DateTime.now())) { |
| existingRequestIterator.remove(); |
| } else { |
| if (request.lock().tryLock( |
| request.leaseDurationMillis())) { |
| request.future().complete(null); |
| existingRequestIterator.remove(); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| private class LockRequest { |
| |
| private final Lock lock; |
| private final DateTime expirationTime; |
| private final int leaseDurationMillis; |
| private final CompletableFuture<Void> future; |
| |
| public LockRequest(Lock lock, long waitTimeMillis, |
| int leaseDurationMillis, CompletableFuture<Void> future) { |
| |
| this.lock = lock; |
| this.expirationTime = DateTime.now().plusMillis( |
| (int) waitTimeMillis); |
| this.leaseDurationMillis = leaseDurationMillis; |
| this.future = future; |
| } |
| |
| public Lock lock() { |
| return lock; |
| } |
| |
| public DateTime expirationTime() { |
| return expirationTime; |
| } |
| |
| public int leaseDurationMillis() { |
| return leaseDurationMillis; |
| } |
| |
| public CompletableFuture<Void> future() { |
| return future; |
| } |
| } |
| } |