2 * Copyright (c) 2016 Cisco Systems, Inc. and others. All rights reserved.
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
8 package org.opendaylight.controller.cluster.databroker.actors.dds;
10 import akka.actor.ActorRef;
11 import akka.actor.Status;
12 import com.google.common.base.Throwables;
13 import com.google.common.base.Verify;
15 import java.util.concurrent.ConcurrentHashMap;
16 import java.util.concurrent.atomic.AtomicLong;
17 import java.util.function.Consumer;
18 import org.opendaylight.controller.cluster.access.client.ClientActorBehavior;
19 import org.opendaylight.controller.cluster.access.client.ClientActorContext;
20 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
21 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
22 import org.opendaylight.controller.cluster.access.concepts.Response;
23 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
24 import org.slf4j.Logger;
25 import org.slf4j.LoggerFactory;
28 * {@link ClientActorBehavior} acting as an intermediary between the backend actors and the DistributedDataStore
32 * This class is not visible outside of this package because it breaks the actor containment. Services provided to
33 * Java world outside of actor containment are captured in {@link DistributedDataStoreClient}.
36 * IMPORTANT: this class breaks actor containment via methods implementing {@link DistributedDataStoreClient} contract.
37 * When touching internal state, be mindful of the execution context from which execution context, Actor
38 * or POJO, is the state being accessed or modified.
41 * THREAD SAFETY: this class must always be kept thread-safe, so that both the Actor System thread and the application
42 * threads can run concurrently. All state transitions must be made in a thread-safe manner. When in
43 * doubt, feel free to synchronize on this object.
46 * PERFORMANCE: this class lies in a performance-critical fast path. All code needs to be concise and efficient, but
47 * performance must not come at the price of correctness. Any optimizations need to be carefully analyzed
48 * for correctness and performance impact.
51 * TRADE-OFFS: part of the functionality runs in application threads without switching contexts, which makes it ideal
52 * for performing work and charging applications for it. That has two positive effects:
53 * - CPU usage is distributed across applications, minimizing work done in the actor thread
54 * - CPU usage provides back-pressure towards the application.
56 * @author Robert Varga
58 final class DistributedDataStoreClientBehavior extends ClientActorBehavior implements DistributedDataStoreClient {
59 private static final Logger LOG = LoggerFactory.getLogger(DistributedDataStoreClientBehavior.class);
61 private final Map<LocalHistoryIdentifier, ClientLocalHistory> histories = new ConcurrentHashMap<>();
62 private final AtomicLong nextHistoryId = new AtomicLong(1);
63 private final ModuleShardBackendResolver resolver;
64 private final SingleClientHistory singleHistory;
66 private volatile Throwable aborted;
68 DistributedDataStoreClientBehavior(final ClientActorContext context, final ActorContext actorContext) {
70 resolver = new ModuleShardBackendResolver(context.getIdentifier(), actorContext);
71 singleHistory = new SingleClientHistory(this, new LocalHistoryIdentifier(getIdentifier(), 0));
76 // Methods below are invoked from the client actor thread
81 protected void haltClient(final Throwable cause) {
82 // If we have encountered a previous problem there is not cleanup necessary, as we have already cleaned up
83 // Thread safely is not an issue, as both this method and any failures are executed from the same (client actor)
85 if (aborted != null) {
86 abortOperations(cause);
90 private void abortOperations(final Throwable cause) {
91 // This acts as a barrier, application threads check this after they have added an entry in the maps,
92 // and if they observe aborted being non-null, they will perform their cleanup and not return the handle.
95 for (ClientLocalHistory h : histories.values()) {
101 private DistributedDataStoreClientBehavior shutdown(final ClientActorBehavior currentBehavior) {
102 abortOperations(new IllegalStateException("Client " + getIdentifier() + " has been shut down"));
107 protected DistributedDataStoreClientBehavior onCommand(final Object command) {
108 if (command instanceof GetClientRequest) {
109 ((GetClientRequest) command).getReplyTo().tell(new Status.Success(this), ActorRef.noSender());
111 LOG.warn("{}: ignoring unhandled command {}", persistenceId(), command);
119 // Methods below are invoked from application threads
123 @SuppressWarnings("checkstyle:IllegalCatch")
124 private static <K, V extends LocalAbortable> V returnIfOperational(final Map<K , V> map, final K key, final V value,
125 final Throwable aborted) {
126 Verify.verify(map.put(key, value) == null);
128 if (aborted != null) {
130 value.localAbort(aborted);
131 } catch (Exception e) {
132 LOG.debug("Close of {} failed", value, e);
134 map.remove(key, value);
135 throw Throwables.propagate(aborted);
142 public ClientLocalHistory createLocalHistory() {
143 final LocalHistoryIdentifier historyId = new LocalHistoryIdentifier(getIdentifier(),
144 nextHistoryId.getAndIncrement());
145 final ClientLocalHistory history = new ClientLocalHistory(this, historyId);
146 LOG.debug("{}: creating a new local history {}", persistenceId(), history);
148 return returnIfOperational(histories, historyId, history, aborted);
152 public ClientTransaction createTransaction() {
153 return singleHistory.createTransaction();
157 public void close() {
158 context().executeInActor(this::shutdown);
162 protected ModuleShardBackendResolver resolver() {
166 void sendRequest(final TransactionRequest<?> request, final Consumer<Response<?, ?>> completer) {
167 sendRequest(request, response -> {
168 completer.accept(response);