/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.runtime.heartbeat;
import org.apache.flink.runtime.clusterframework.types.ResourceID;
import org.apache.flink.runtime.concurrent.AcceptFunction;
import org.apache.flink.runtime.concurrent.ApplyFunction;
import org.apache.flink.runtime.concurrent.Future;
import org.apache.flink.runtime.concurrent.ScheduledExecutor;
import org.apache.flink.util.Preconditions;
import org.slf4j.Logger;
import javax.annotation.concurrent.ThreadSafe;
import java.util.Collection;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executor;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
/**
* Heartbeat manager implementation. The heartbeat manager maintains a map of heartbeat monitors
* and resource IDs. Each monitor will be updated when a new heartbeat of the associated machine has
* been received. If the monitor detects that a heartbeat has timed out, it will notify the
* {@link HeartbeatListener} about it. A heartbeat times out iff no heartbeat signal has been
* received within a given timeout interval.
*
* @param <I> Type of the incoming heartbeat payload
* @param <O> Type of the outgoing heartbeat payload
*/
@ThreadSafe
public class HeartbeatManagerImpl<I, O> implements HeartbeatManager<I, O> {
/** Heartbeat timeout interval in milli seconds */
private final long heartbeatTimeoutIntervalMs;
/** Resource ID which is used to mark one own's heartbeat signals */
private final ResourceID ownResourceID;
/** Heartbeat listener with which the heartbeat manager has been associated */
private final HeartbeatListener<I, O> heartbeatListener;
/** Executor service used to run heartbeat timeout notifications */
private final ScheduledExecutor scheduledExecutor;
protected final Logger log;
/** Map containing the heartbeat monitors associated with the respective resource ID */
private final ConcurrentHashMap<ResourceID, HeartbeatManagerImpl.HeartbeatMonitor<O>> heartbeatTargets;
/** Execution context used to run future callbacks */
private final Executor executor;
/** Running state of the heartbeat manager */
protected volatile boolean stopped;
public HeartbeatManagerImpl(
long heartbeatTimeoutIntervalMs,
ResourceID ownResourceID,
HeartbeatListener<I, O> heartbeatListener,
Executor executor,
ScheduledExecutor scheduledExecutor,
Logger log) {
Preconditions.checkArgument(heartbeatTimeoutIntervalMs > 0L, "The heartbeat timeout has to be larger than 0.");
this.heartbeatTimeoutIntervalMs = heartbeatTimeoutIntervalMs;
this.ownResourceID = Preconditions.checkNotNull(ownResourceID);
this.heartbeatListener = Preconditions.checkNotNull(heartbeatListener, "heartbeatListener");
this.scheduledExecutor = Preconditions.checkNotNull(scheduledExecutor);
this.log = Preconditions.checkNotNull(log);
this.executor = Preconditions.checkNotNull(executor);
this.heartbeatTargets = new ConcurrentHashMap<>(16);
stopped = false;
}
//----------------------------------------------------------------------------------------------
// Getters
//----------------------------------------------------------------------------------------------
ResourceID getOwnResourceID() {
return ownResourceID;
}
Executor getExecutor() {
return executor;
}
HeartbeatListener<I, O> getHeartbeatListener() {
return heartbeatListener;
}
Collection<HeartbeatManagerImpl.HeartbeatMonitor<O>> getHeartbeatTargets() {
return heartbeatTargets.values();
}
//----------------------------------------------------------------------------------------------
// HeartbeatManager methods
//----------------------------------------------------------------------------------------------
@Override
public void monitorTarget(ResourceID resourceID, HeartbeatTarget<O> heartbeatTarget) {
if (!stopped) {
if (heartbeatTargets.containsKey(resourceID)) {
log.info("The target with resource ID {} is already been monitored.", resourceID);
} else {
HeartbeatManagerImpl.HeartbeatMonitor<O> heartbeatMonitor = new HeartbeatManagerImpl.HeartbeatMonitor<>(
resourceID,
heartbeatTarget,
scheduledExecutor,
heartbeatListener,
heartbeatTimeoutIntervalMs);
heartbeatTargets.put(
resourceID,
heartbeatMonitor);
// check if we have stopped in the meantime (concurrent stop operation)
if (stopped) {
heartbeatMonitor.cancel();
heartbeatTargets.remove(resourceID);
}
}
}
}
@Override
public void unmonitorTarget(ResourceID resourceID) {
if (!stopped) {
HeartbeatManagerImpl.HeartbeatMonitor<O> heartbeatMonitor = heartbeatTargets.remove(resourceID);
if (heartbeatMonitor != null) {
heartbeatMonitor.cancel();
}
}
}
@Override
public void stop() {
stopped = true;
for (HeartbeatManagerImpl.HeartbeatMonitor<O> heartbeatMonitor : heartbeatTargets.values()) {
heartbeatMonitor.cancel();
}
heartbeatTargets.clear();
}
//----------------------------------------------------------------------------------------------
// HeartbeatTarget methods
//----------------------------------------------------------------------------------------------
@Override
public void receiveHeartbeat(ResourceID heartbeatOrigin, I heartbeatPayload) {
if (!stopped) {
log.debug("Received heartbeat from {}.", heartbeatOrigin);
reportHeartbeat(heartbeatOrigin);
if (heartbeatPayload != null) {
heartbeatListener.reportPayload(heartbeatOrigin, heartbeatPayload);
}
}
}
@Override
public void requestHeartbeat(final ResourceID requestOrigin, I heartbeatPayload) {
if (!stopped) {
log.debug("Received heartbeat request from {}.", requestOrigin);
final HeartbeatTarget<O> heartbeatTarget = reportHeartbeat(requestOrigin);
if (heartbeatTarget != null) {
if (heartbeatPayload != null) {
heartbeatListener.reportPayload(requestOrigin, heartbeatPayload);
}
Future<O> futurePayload = heartbeatListener.retrievePayload();
if (futurePayload != null) {
Future<Void> sendHeartbeatFuture = futurePayload.thenAcceptAsync(new AcceptFunction<O>() {
@Override
public void accept(O retrievedPayload) {
heartbeatTarget.receiveHeartbeat(getOwnResourceID(), retrievedPayload);
}
}, executor);
sendHeartbeatFuture.exceptionally(new ApplyFunction<Throwable, Void>() {
@Override
public Void apply(Throwable failure) {
log.warn("Could not send heartbeat to target with id {}.", requestOrigin, failure);
return null;
}
});
} else {
heartbeatTarget.receiveHeartbeat(ownResourceID, null);
}
}
}
}
HeartbeatTarget<O> reportHeartbeat(ResourceID resourceID) {
if (heartbeatTargets.containsKey(resourceID)) {
HeartbeatManagerImpl.HeartbeatMonitor<O> heartbeatMonitor = heartbeatTargets.get(resourceID);
heartbeatMonitor.reportHeartbeat();
return heartbeatMonitor.getHeartbeatTarget();
} else {
return null;
}
}
//----------------------------------------------------------------------------------------------
// Utility classes
//----------------------------------------------------------------------------------------------
/**
* Heartbeat monitor which manages the heartbeat state of the associated heartbeat target. The
* monitor notifies the {@link HeartbeatListener} whenever it has not seen a heartbeat signal
* in the specified heartbeat timeout interval. Each heartbeat signal resets this timer.
*
* @param <O> Type of the payload being sent to the associated heartbeat target
*/
static class HeartbeatMonitor<O> implements Runnable {
/** Resource ID of the monitored heartbeat target */
private final ResourceID resourceID;
/** Associated heartbeat target */
private final HeartbeatTarget<O> heartbeatTarget;
private final ScheduledExecutor scheduledExecutor;
/** Listener which is notified about heartbeat timeouts */
private final HeartbeatListener<?, ?> heartbeatListener;
/** Maximum heartbeat timeout interval */
private final long heartbeatTimeoutIntervalMs;
private volatile ScheduledFuture<?> futureTimeout;
private final AtomicReference<State> state = new AtomicReference<>(State.RUNNING);
HeartbeatMonitor(
ResourceID resourceID,
HeartbeatTarget<O> heartbeatTarget,
ScheduledExecutor scheduledExecutor,
HeartbeatListener<?, O> heartbeatListener,
long heartbeatTimeoutIntervalMs) {
this.resourceID = Preconditions.checkNotNull(resourceID);
this.heartbeatTarget = Preconditions.checkNotNull(heartbeatTarget);
this.scheduledExecutor = Preconditions.checkNotNull(scheduledExecutor);
this.heartbeatListener = Preconditions.checkNotNull(heartbeatListener);
Preconditions.checkArgument(heartbeatTimeoutIntervalMs >= 0L, "The heartbeat timeout interval has to be larger than 0.");
this.heartbeatTimeoutIntervalMs = heartbeatTimeoutIntervalMs;
resetHeartbeatTimeout(heartbeatTimeoutIntervalMs);
}
HeartbeatTarget<O> getHeartbeatTarget() {
return heartbeatTarget;
}
void reportHeartbeat() {
resetHeartbeatTimeout(heartbeatTimeoutIntervalMs);
}
void resetHeartbeatTimeout(long heartbeatTimeout) {
if (state.get() == State.RUNNING) {
cancelTimeout();
futureTimeout = scheduledExecutor.schedule(this, heartbeatTimeout, TimeUnit.MILLISECONDS);
// Double check for concurrent accesses (e.g. a firing of the scheduled future)
if (state.get() != State.RUNNING) {
cancelTimeout();
}
}
}
void cancel() {
// we can only cancel if we are in state running
if (state.compareAndSet(State.RUNNING, State.CANCELED)) {
cancelTimeout();
}
}
private void cancelTimeout() {
if (futureTimeout != null) {
futureTimeout.cancel(true);
}
}
public boolean isCanceled() {
return state.get() == State.CANCELED;
}
@Override
public void run() {
// The heartbeat has timed out if we're in state running
if (state.compareAndSet(State.RUNNING, State.TIMEOUT)) {
heartbeatListener.notifyHeartbeatTimeout(resourceID);
}
}
private enum State {
RUNNING,
TIMEOUT,
CANCELED
}
}
}