| package org.onlab.onos.store.service.impl; |
| |
| import static org.onlab.util.Tools.namedThreads; |
| import static org.slf4j.LoggerFactory.getLogger; |
| |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Set; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| |
| 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.DatabaseAdminService; |
| import org.onlab.onos.store.service.DatabaseException; |
| 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.LinkedListMultimap; |
| import com.google.common.collect.ListMultimap; |
| import com.google.common.collect.Multimaps; |
| |
| @Component(immediate = true) |
| @Service |
| public class DistributedLockManager implements LockService { |
| |
| private static final ExecutorService THREAD_POOL = |
| Executors.newCachedThreadPool(namedThreads("lock-manager-%d")); |
| |
| private final Logger log = getLogger(getClass()); |
| |
| public static final String ONOS_LOCK_TABLE_NAME = "onos-locks"; |
| |
| public static final int DEAD_LOCK_TIMEOUT_MS = 5000; |
| |
| private final ListMultimap<String, LockRequest> locksToAcquire = |
| Multimaps.synchronizedListMultimap(LinkedListMultimap.<String, LockRequest>create()); |
| |
| @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| private ClusterCommunicationService clusterCommunicator; |
| |
| @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| private DatabaseAdminService databaseAdminService; |
| |
| @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| private DatabaseService databaseService; |
| |
| @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) |
| private ClusterService clusterService; |
| |
| @Activate |
| public void activate() { |
| try { |
| Set<String> tables = databaseAdminService.listTables(); |
| |
| if (!tables.contains(ONOS_LOCK_TABLE_NAME)) { |
| if (databaseAdminService.createTable(ONOS_LOCK_TABLE_NAME, DEAD_LOCK_TIMEOUT_MS)) { |
| log.info("Created {} table.", ONOS_LOCK_TABLE_NAME); |
| } |
| } |
| } catch (DatabaseException e) { |
| log.error("DistributedLockManager#activate failed.", e); |
| } |
| |
| clusterCommunicator.addSubscriber( |
| DatabaseStateMachine.DATABASE_UPDATE_EVENTS, |
| new LockEventMessageListener()); |
| |
| log.info("Started"); |
| } |
| |
| @Deactivate |
| public void deactivate() { |
| clusterCommunicator.removeSubscriber(DatabaseStateMachine.DATABASE_UPDATE_EVENTS); |
| locksToAcquire.clear(); |
| log.info("Stopped."); |
| } |
| |
| @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(); |
| } |
| |
| /** |
| * Attempts to acquire the lock as soon as it becomes available. |
| * @param lock lock to acquire. |
| * @param waitTimeMillis maximum time to wait before giving up. |
| * @param leaseDurationMillis the duration for which to acquire the lock initially. |
| * @return Future that can be blocked on until lock becomes available. |
| */ |
| protected CompletableFuture<Void> lockIfAvailable( |
| Lock lock, |
| int waitTimeMillis, |
| int leaseDurationMillis) { |
| CompletableFuture<Void> future = new CompletableFuture<>(); |
| LockRequest request = new LockRequest( |
| lock, |
| leaseDurationMillis, |
| DateTime.now().plusMillis(waitTimeMillis), |
| future); |
| locksToAcquire.put(lock.path(), request); |
| return future; |
| } |
| |
| /** |
| * Attempts to acquire the lock as soon as it becomes available. |
| * @param lock lock to acquire. |
| * @param leaseDurationMillis the duration for which to acquire the lock initially. |
| * @return Future lease expiration date. |
| */ |
| protected CompletableFuture<Void> lockIfAvailable( |
| Lock lock, |
| int leaseDurationMillis) { |
| CompletableFuture<Void> future = new CompletableFuture<>(); |
| LockRequest request = new LockRequest( |
| lock, |
| leaseDurationMillis, |
| DateTime.now().plusYears(100), |
| future); |
| locksToAcquire.put(lock.path(), request); |
| return future; |
| } |
| |
| private class LockEventMessageListener implements ClusterMessageHandler { |
| @Override |
| public void handle(ClusterMessage message) { |
| TableModificationEvent event = ClusterMessagingProtocol.DB_SERIALIZER |
| .decode(message.payload()); |
| if (event.tableName().equals(ONOS_LOCK_TABLE_NAME) && |
| event.type().equals(TableModificationEvent.Type.ROW_DELETED)) { |
| THREAD_POOL.submit(new RetryLockTask(event.key())); |
| } |
| } |
| } |
| |
| private class RetryLockTask implements Runnable { |
| |
| private final String path; |
| |
| public RetryLockTask(String path) { |
| this.path = path; |
| } |
| |
| @Override |
| public void run() { |
| if (!locksToAcquire.containsKey(path)) { |
| return; |
| } |
| |
| List<LockRequest> existingRequests = locksToAcquire.get(path); |
| if (existingRequests == null || existingRequests.isEmpty()) { |
| return; |
| } |
| log.info("Path {} is now available for locking. There are {} outstanding " |
| + "requests for it.", |
| path, existingRequests.size()); |
| |
| synchronized (existingRequests) { |
| Iterator<LockRequest> existingRequestIterator = existingRequests.iterator(); |
| while (existingRequestIterator.hasNext()) { |
| LockRequest request = existingRequestIterator.next(); |
| if (DateTime.now().isAfter(request.requestExpirationTime())) { |
| // request expired. |
| 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 requestExpirationTime; |
| private final int leaseDurationMillis; |
| private final CompletableFuture<Void> future; |
| |
| public LockRequest( |
| Lock lock, |
| int leaseDurationMillis, |
| DateTime requestExpirationTime, |
| CompletableFuture<Void> future) { |
| |
| this.lock = lock; |
| this.requestExpirationTime = requestExpirationTime; |
| this.leaseDurationMillis = leaseDurationMillis; |
| this.future = future; |
| } |
| |
| public Lock lock() { |
| return lock; |
| } |
| |
| public DateTime requestExpirationTime() { |
| return requestExpirationTime; |
| } |
| |
| public int leaseDurationMillis() { |
| return leaseDurationMillis; |
| } |
| |
| public CompletableFuture<Void> future() { |
| return future; |
| } |
| } |
| } |