/*
* Copyright (c) 2016 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.controller.cluster.databroker.actors.dds;
import static com.google.common.base.Preconditions.checkArgument;
import static java.util.Objects.requireNonNull;
import akka.actor.ActorRef;
import akka.util.Timeout;
import com.google.common.primitives.UnsignedLong;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Consumer;
import org.checkerframework.checker.lock.qual.GuardedBy;
import org.eclipse.jdt.annotation.NonNull;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.controller.cluster.access.ABIVersion;
import org.opendaylight.controller.cluster.access.client.BackendInfoResolver;
import org.opendaylight.controller.cluster.access.commands.ConnectClientRequest;
import org.opendaylight.controller.cluster.access.commands.ConnectClientSuccess;
import org.opendaylight.controller.cluster.access.commands.NotLeaderException;
import org.opendaylight.controller.cluster.access.concepts.ClientIdentifier;
import org.opendaylight.controller.cluster.access.concepts.RequestFailure;
import org.opendaylight.controller.cluster.common.actor.ExplicitAsk;
import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
import org.opendaylight.controller.cluster.datastore.exceptions.NotInitializedException;
import org.opendaylight.controller.cluster.datastore.exceptions.PrimaryNotFoundException;
import org.opendaylight.controller.cluster.datastore.messages.PrimaryShardInfo;
import org.opendaylight.controller.cluster.datastore.utils.ActorUtils;
import org.opendaylight.yangtools.concepts.Registration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import scala.Function1;
import scala.compat.java8.FutureConverters;
/**
* {@link BackendInfoResolver} implementation for static shard configuration based on ShardManager. Each string-named
* shard is assigned a single cookie and this mapping is stored in a bidirectional map. Information about corresponding
* shard leader is resolved via {@link ActorUtils}. The product of resolution is {@link ShardBackendInfo}.
*
*
* This class is thread-safe.
*
* @author Robert Varga
*/
abstract class AbstractShardBackendResolver extends BackendInfoResolver {
static final class ShardState {
private final CompletionStage stage;
@GuardedBy("this")
private ShardBackendInfo result;
ShardState(final CompletionStage stage) {
this.stage = requireNonNull(stage);
stage.whenComplete(this::onStageResolved);
}
@NonNull CompletionStage getStage() {
return stage;
}
synchronized @Nullable ShardBackendInfo getResult() {
return result;
}
private synchronized void onStageResolved(final ShardBackendInfo info, final Throwable failure) {
if (failure == null) {
this.result = requireNonNull(info);
} else {
LOG.warn("Failed to resolve shard", failure);
}
}
}
private static final Logger LOG = LoggerFactory.getLogger(AbstractShardBackendResolver.class);
/**
* Connect request timeout. If the shard does not respond within this interval, we retry the lookup and connection.
*/
// TODO: maybe make this configurable somehow?
private static final Timeout CONNECT_TIMEOUT = Timeout.apply(5, TimeUnit.SECONDS);
private final AtomicLong nextSessionId = new AtomicLong();
private final Function1 connectFunction;
private final ActorUtils actorUtils;
private final Set> staleBackendInfoCallbacks = ConcurrentHashMap.newKeySet();
// FIXME: we really need just ActorContext.findPrimaryShardAsync()
AbstractShardBackendResolver(final ClientIdentifier clientId, final ActorUtils actorUtils) {
this.actorUtils = requireNonNull(actorUtils);
this.connectFunction = ExplicitAsk.toScala(t -> new ConnectClientRequest(clientId, t, ABIVersion.BORON,
ABIVersion.current()));
}
@Override
public Registration notifyWhenBackendInfoIsStale(final Consumer callback) {
staleBackendInfoCallbacks.add(callback);
return () -> staleBackendInfoCallbacks.remove(callback);
}
protected void notifyStaleBackendInfoCallbacks(Long cookie) {
staleBackendInfoCallbacks.forEach(callback -> callback.accept(cookie));
}
protected ActorUtils actorUtils() {
return actorUtils;
}
protected final void flushCache(final String shardName) {
actorUtils.getPrimaryShardInfoCache().remove(shardName);
}
protected final ShardState resolveBackendInfo(final String shardName, final long cookie) {
LOG.debug("Resolving cookie {} to shard {}", cookie, shardName);
final CompletableFuture future = new CompletableFuture<>();
FutureConverters.toJava(actorUtils.findPrimaryShardAsync(shardName)).whenComplete((info, failure) -> {
if (failure == null) {
connectShard(shardName, cookie, info, future);
return;
}
LOG.debug("Shard {} failed to resolve", shardName, failure);
if (failure instanceof NoShardLeaderException) {
future.completeExceptionally(wrap("Shard has no current leader", failure));
} else if (failure instanceof NotInitializedException) {
// FIXME: this actually is an exception we can retry on
LOG.info("Shard {} has not initialized yet", shardName);
future.completeExceptionally(failure);
} else if (failure instanceof PrimaryNotFoundException) {
LOG.info("Failed to find primary for shard {}", shardName);
future.completeExceptionally(failure);
} else {
future.completeExceptionally(failure);
}
});
return new ShardState(future);
}
private static TimeoutException wrap(final String message, final Throwable cause) {
final TimeoutException ret = new TimeoutException(message);
ret.initCause(requireNonNull(cause));
return ret;
}
private void connectShard(final String shardName, final long cookie, final PrimaryShardInfo info,
final CompletableFuture future) {
LOG.debug("Shard {} resolved to {}, attempting to connect", shardName, info);
FutureConverters.toJava(ExplicitAsk.ask(info.getPrimaryShardActor(), connectFunction, CONNECT_TIMEOUT))
.whenComplete((response, failure) -> onConnectResponse(shardName, cookie, future, response, failure));
}
private void onConnectResponse(final String shardName, final long cookie,
final CompletableFuture future, final Object response, final Throwable failure) {
if (failure != null) {
LOG.debug("Connect attempt to {} failed, will retry", shardName, failure);
future.completeExceptionally(wrap("Connection attempt failed", failure));
return;
}
if (response instanceof RequestFailure) {
final Throwable cause = ((RequestFailure, ?>) response).getCause().unwrap();
LOG.debug("Connect attempt to {} failed to process", shardName, cause);
final Throwable result = cause instanceof NotLeaderException
? wrap("Leader moved during establishment", cause) : cause;
future.completeExceptionally(result);
return;
}
LOG.debug("Resolved backend information to {}", response);
checkArgument(response instanceof ConnectClientSuccess, "Unhandled response %s", response);
final ConnectClientSuccess success = (ConnectClientSuccess) response;
future.complete(new ShardBackendInfo(success.getBackend(), nextSessionId.getAndIncrement(),
success.getVersion(), shardName, UnsignedLong.fromLongBits(cookie), success.getDataTree(),
success.getMaxMessages()));
}
}