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The MongoDB Java Driver uber-artifact, containing the legacy driver, the mongodb-driver, mongodb-driver-core, and bson
/*
* Copyright 2008-present MongoDB, Inc.
*
* Licensed 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 com.mongodb.internal.connection;
import com.mongodb.MongoSocketException;
import com.mongodb.annotations.ThreadSafe;
import com.mongodb.connection.ServerDescription;
import com.mongodb.connection.ServerId;
import com.mongodb.connection.ServerSettings;
import com.mongodb.diagnostics.logging.Logger;
import com.mongodb.diagnostics.logging.Loggers;
import com.mongodb.event.ServerHeartbeatFailedEvent;
import com.mongodb.event.ServerHeartbeatStartedEvent;
import com.mongodb.event.ServerHeartbeatSucceededEvent;
import com.mongodb.event.ServerMonitorListener;
import org.bson.BsonDocument;
import org.bson.BsonInt32;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import static com.mongodb.assertions.Assertions.notNull;
import static com.mongodb.connection.ServerConnectionState.CONNECTING;
import static com.mongodb.connection.ServerType.UNKNOWN;
import static com.mongodb.internal.connection.CommandHelper.executeCommand;
import static com.mongodb.internal.connection.DescriptionHelper.createServerDescription;
import static com.mongodb.internal.event.EventListenerHelper.getServerMonitorListener;
import static java.lang.String.format;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
@ThreadSafe
class DefaultServerMonitor implements ServerMonitor {
private static final Logger LOGGER = Loggers.getLogger("cluster");
private final ServerId serverId;
private final ServerMonitorListener serverMonitorListener;
private final ClusterClock clusterClock;
private final ChangeListener serverStateListener;
private final InternalConnectionFactory internalConnectionFactory;
private final ConnectionPool connectionPool;
private final ServerSettings serverSettings;
private final ServerMonitorRunnable monitor;
private final Thread monitorThread;
private final Lock lock = new ReentrantLock();
private final Condition condition = lock.newCondition();
private volatile boolean isClosed;
DefaultServerMonitor(final ServerId serverId, final ServerSettings serverSettings,
final ClusterClock clusterClock, final ChangeListener serverStateListener,
final InternalConnectionFactory internalConnectionFactory, final ConnectionPool connectionPool) {
this.serverSettings = notNull("serverSettings", serverSettings);
this.serverId = notNull("serverId", serverId);
this.serverMonitorListener = getServerMonitorListener(serverSettings);
this.clusterClock = notNull("clusterClock", clusterClock);
this.serverStateListener = serverStateListener;
this.internalConnectionFactory = notNull("internalConnectionFactory", internalConnectionFactory);
this.connectionPool = connectionPool;
monitor = new ServerMonitorRunnable();
monitorThread = new Thread(monitor, "cluster-" + this.serverId.getClusterId() + "-" + this.serverId.getAddress());
monitorThread.setDaemon(true);
isClosed = false;
}
@Override
public void start() {
monitorThread.start();
}
@Override
public void connect() {
lock.lock();
try {
condition.signal();
} finally {
lock.unlock();
}
}
@Override
public void close() {
isClosed = true;
monitorThread.interrupt();
}
class ServerMonitorRunnable implements Runnable {
private final ExponentiallyWeightedMovingAverage averageRoundTripTime = new ExponentiallyWeightedMovingAverage(0.2);
@Override
@SuppressWarnings("unchecked")
public synchronized void run() {
InternalConnection connection = null;
try {
ServerDescription currentServerDescription = getConnectingServerDescription(null);
while (!isClosed) {
ServerDescription previousServerDescription = currentServerDescription;
try {
if (connection == null) {
connection = internalConnectionFactory.create(serverId);
try {
connection.open();
} catch (Throwable t) {
connection = null;
throw t;
}
}
try {
currentServerDescription = lookupServerDescription(connection);
} catch (MongoSocketException e) {
connectionPool.invalidate();
connection.close();
connection = null;
connection = internalConnectionFactory.create(serverId);
try {
connection.open();
} catch (Throwable t) {
connection = null;
throw t;
}
try {
currentServerDescription = lookupServerDescription(connection);
} catch (MongoSocketException e1) {
connection.close();
connection = null;
throw e1;
}
}
} catch (Throwable t) {
averageRoundTripTime.reset();
currentServerDescription = getConnectingServerDescription(t);
}
if (!isClosed) {
try {
logStateChange(previousServerDescription, currentServerDescription);
serverStateListener.stateChanged(new ChangeEvent(previousServerDescription,
currentServerDescription));
} catch (Throwable t) {
LOGGER.warn("Exception in monitor thread during notification of server description state change", t);
}
waitForNext();
}
}
} finally {
if (connection != null) {
connection.close();
}
}
}
private ServerDescription getConnectingServerDescription(final Throwable exception) {
return ServerDescription.builder().type(UNKNOWN).state(CONNECTING).address(serverId.getAddress()).exception(exception).build();
}
private ServerDescription lookupServerDescription(final InternalConnection connection) {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug(format("Checking status of %s", serverId.getAddress()));
}
serverMonitorListener.serverHearbeatStarted(new ServerHeartbeatStartedEvent(connection.getDescription().getConnectionId()));
long start = System.nanoTime();
try {
BsonDocument isMasterResult =
executeCommand("admin", new BsonDocument("ismaster", new BsonInt32(1)), clusterClock, connection);
long elapsedTimeNanos = System.nanoTime() - start;
averageRoundTripTime.addSample(elapsedTimeNanos);
serverMonitorListener.serverHeartbeatSucceeded(
new ServerHeartbeatSucceededEvent(connection.getDescription().getConnectionId(), isMasterResult, elapsedTimeNanos));
return createServerDescription(serverId.getAddress(), isMasterResult, connection.getDescription().getServerVersion(),
averageRoundTripTime.getAverage());
} catch (RuntimeException e) {
serverMonitorListener.serverHeartbeatFailed(
new ServerHeartbeatFailedEvent(connection.getDescription().getConnectionId(), System.nanoTime() - start, e));
throw e;
}
}
private void logStateChange(final ServerDescription previousServerDescription,
final ServerDescription currentServerDescription) {
if (shouldLogStageChange(previousServerDescription, currentServerDescription)) {
if (currentServerDescription.getException() != null) {
LOGGER.info(format("Exception in monitor thread while connecting to server %s", serverId.getAddress()),
currentServerDescription.getException());
} else {
LOGGER.info(format("Monitor thread successfully connected to server with description %s", currentServerDescription));
}
}
}
private void waitForNext() {
try {
long timeRemaining = waitForSignalOrTimeout();
if (timeRemaining > 0) {
long timeWaiting = serverSettings.getHeartbeatFrequency(NANOSECONDS) - timeRemaining;
long minimumNanosToWait = serverSettings.getMinHeartbeatFrequency(NANOSECONDS);
if (timeWaiting < minimumNanosToWait) {
long millisToSleep = MILLISECONDS.convert(minimumNanosToWait - timeWaiting, NANOSECONDS);
if (millisToSleep > 0) {
Thread.sleep(millisToSleep);
}
}
}
} catch (InterruptedException e) {
// fall through
}
}
private long waitForSignalOrTimeout() throws InterruptedException {
lock.lock();
try {
return condition.awaitNanos(serverSettings.getHeartbeatFrequency(NANOSECONDS));
} finally {
lock.unlock();
}
}
}
static boolean shouldLogStageChange(final ServerDescription previous, final ServerDescription current) {
if (previous.isOk() != current.isOk()) {
return true;
}
if (!previous.getAddress().equals(current.getAddress())) {
return true;
}
if (previous.getCanonicalAddress() != null
? !previous.getCanonicalAddress().equals(current.getCanonicalAddress()) : current.getCanonicalAddress() != null) {
return true;
}
if (!previous.getHosts().equals(current.getHosts())) {
return true;
}
if (!previous.getArbiters().equals(current.getArbiters())) {
return true;
}
if (!previous.getPassives().equals(current.getPassives())) {
return true;
}
if (previous.getPrimary() != null ? !previous.getPrimary().equals(current.getPrimary()) : current.getPrimary() != null) {
return true;
}
if (previous.getSetName() != null ? !previous.getSetName().equals(current.getSetName()) : current.getSetName() != null) {
return true;
}
if (previous.getState() != current.getState()) {
return true;
}
if (!previous.getTagSet().equals(current.getTagSet())) {
return true;
}
if (previous.getType() != current.getType()) {
return true;
}
if (!previous.getVersion().equals(current.getVersion())) {
return true;
}
if (previous.getElectionId() != null
? !previous.getElectionId().equals(current.getElectionId()) : current.getElectionId() != null) {
return true;
}
if (previous.getSetVersion() != null
? !previous.getSetVersion().equals(current.getSetVersion()) : current.getSetVersion() != null) {
return true;
}
// Compare class equality and message as exceptions rarely override equals
Class thisExceptionClass = previous.getException() != null ? previous.getException().getClass() : null;
Class thatExceptionClass = current.getException() != null ? current.getException().getClass() : null;
if (thisExceptionClass != null ? !thisExceptionClass.equals(thatExceptionClass) : thatExceptionClass != null) {
return true;
}
String thisExceptionMessage = previous.getException() != null ? previous.getException().getMessage() : null;
String thatExceptionMessage = current.getException() != null ? current.getException().getMessage() : null;
if (thisExceptionMessage != null ? !thisExceptionMessage.equals(thatExceptionMessage) : thatExceptionMessage != null) {
return true;
}
return false;
}
}