/*
* 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.activemq.artemis.core.server.impl;
import java.io.File;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileLock;
import org.apache.activemq.artemis.api.core.ActiveMQIllegalStateException;
import org.apache.activemq.artemis.api.core.SimpleString;
import org.apache.activemq.artemis.core.server.ActivateCallback;
import org.apache.activemq.artemis.core.server.ActiveMQServerLogger;
import org.apache.activemq.artemis.core.server.NodeManager;
import org.apache.activemq.artemis.utils.UUID;
import org.jboss.logging.Logger;
public class FileLockNodeManager extends NodeManager {
private static final Logger logger = Logger.getLogger(FileLockNodeManager.class);
private static final int LIVE_LOCK_POS = 1;
private static final int BACKUP_LOCK_POS = 2;
private static final int LOCK_LENGTH = 1;
private static final byte LIVE = 'L';
private static final byte FAILINGBACK = 'F';
private static final byte PAUSED = 'P';
private static final byte NOT_STARTED = 'N';
private FileLock liveLock;
private FileLock backupLock;
protected long lockAcquisitionTimeout = -1;
protected boolean interrupted = false;
public FileLockNodeManager(final File directory, boolean replicatedBackup) {
super(replicatedBackup, directory);
}
public FileLockNodeManager(final File directory, boolean replicatedBackup, long lockAcquisitionTimeout) {
super(replicatedBackup, directory);
this.lockAcquisitionTimeout = lockAcquisitionTimeout;
}
@Override
public synchronized void start() throws Exception {
if (isStarted()) {
return;
}
if (!replicatedBackup) {
setUpServerLockFile();
}
super.start();
}
@Override
public boolean isAwaitingFailback() throws Exception {
return getState() == FileLockNodeManager.FAILINGBACK;
}
@Override
public boolean isBackupLive() throws Exception {
FileLock liveAttemptLock;
liveAttemptLock = tryLock(FileLockNodeManager.LIVE_LOCK_POS);
if (liveAttemptLock == null) {
return true;
} else {
liveAttemptLock.release();
return false;
}
}
public boolean isLiveLocked() {
return liveLock != null;
}
@Override
public void interrupt() {
interrupted = true;
}
@Override
public final void releaseBackup() throws Exception {
if (backupLock != null) {
backupLock.release();
backupLock = null;
}
}
@Override
public void awaitLiveNode() throws Exception {
do {
byte state = getState();
while (state == FileLockNodeManager.NOT_STARTED || state == FIRST_TIME_START) {
logger.debug("awaiting live node startup state='" + state + "'");
Thread.sleep(2000);
state = getState();
}
liveLock = lock(FileLockNodeManager.LIVE_LOCK_POS);
if (interrupted) {
interrupted = false;
throw new InterruptedException("Lock was interrupted");
}
state = getState();
if (state == FileLockNodeManager.PAUSED) {
liveLock.release();
logger.debug("awaiting live node restarting");
Thread.sleep(2000);
} else if (state == FileLockNodeManager.FAILINGBACK) {
liveLock.release();
logger.debug("awaiting live node failing back");
Thread.sleep(2000);
} else if (state == FileLockNodeManager.LIVE) {
logger.debug("acquired live node lock state = " + (char) state);
break;
}
} while (true);
}
@Override
public void startBackup() throws Exception {
assert !replicatedBackup; // should not be called if this is a replicating backup
ActiveMQServerLogger.LOGGER.waitingToBecomeBackup();
backupLock = lock(FileLockNodeManager.BACKUP_LOCK_POS);
ActiveMQServerLogger.LOGGER.gotBackupLock();
if (getUUID() == null)
readNodeId();
}
@Override
public ActivateCallback startLiveNode() throws Exception {
setFailingBack();
String timeoutMessage = lockAcquisitionTimeout == -1 ? "indefinitely" : lockAcquisitionTimeout + " milliseconds";
ActiveMQServerLogger.LOGGER.waitingToObtainLiveLock(timeoutMessage);
liveLock = lock(FileLockNodeManager.LIVE_LOCK_POS);
ActiveMQServerLogger.LOGGER.obtainedLiveLock();
return new ActivateCallback() {
@Override
public void preActivate() {
}
@Override
public void activated() {
}
@Override
public void deActivate() {
}
@Override
public void activationComplete() {
try {
setLive();
} catch (Exception e) {
ActiveMQServerLogger.LOGGER.warn(e.getMessage(), e);
}
}
};
}
@Override
public void pauseLiveServer() throws Exception {
setPaused();
if (liveLock != null) {
liveLock.release();
}
}
@Override
public void crashLiveServer() throws Exception {
if (liveLock != null) {
liveLock.release();
liveLock = null;
}
}
@Override
public void awaitLiveStatus() throws Exception {
while (getState() != LIVE) {
Thread.sleep(2000);
}
}
private void setLive() throws Exception {
writeFileLockStatus(FileLockNodeManager.LIVE);
}
private void setFailingBack() throws Exception {
writeFileLockStatus(FAILINGBACK);
}
private void setPaused() throws Exception {
writeFileLockStatus(PAUSED);
}
/**
* @param status
* @throws IOException
*/
private void writeFileLockStatus(byte status) throws IOException {
if (replicatedBackup && channel == null)
return;
ByteBuffer bb = ByteBuffer.allocateDirect(1);
bb.put(status);
bb.position(0);
if (!channel.isOpen()) {
setUpServerLockFile();
}
channel.write(bb, 0);
channel.force(true);
}
private byte getState() throws Exception {
ByteBuffer bb = ByteBuffer.allocateDirect(1);
int read;
read = channel.read(bb, 0);
if (read <= 0) {
return FileLockNodeManager.NOT_STARTED;
} else {
return bb.get(0);
}
}
@Override
public final SimpleString readNodeId() throws ActiveMQIllegalStateException, IOException {
ByteBuffer id = ByteBuffer.allocateDirect(16);
int read = channel.read(id, 3);
if (read != 16) {
throw new ActiveMQIllegalStateException("live server did not write id to file");
}
byte[] bytes = new byte[16];
id.position(0);
id.get(bytes);
setUUID(new UUID(UUID.TYPE_TIME_BASED, bytes));
return getNodeId();
}
protected FileLock tryLock(final int lockPos) throws Exception {
try {
return channel.tryLock(lockPos, LOCK_LENGTH, false);
} catch (java.nio.channels.OverlappingFileLockException ex) {
// This just means that another object on the same JVM is holding the lock
return null;
}
}
protected FileLock lock(final int liveLockPos) throws Exception {
long start = System.currentTimeMillis();
while (!interrupted) {
FileLock lock = null;
try {
lock = channel.tryLock(liveLockPos, 1, false);
} catch (java.nio.channels.OverlappingFileLockException ex) {
// This just means that another object on the same JVM is holding the lock
}
if (lock == null) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
return null;
}
if (lockAcquisitionTimeout != -1 && (System.currentTimeMillis() - start) > lockAcquisitionTimeout) {
throw new Exception("timed out waiting for lock");
}
} else {
return lock;
}
}
// todo this is here because sometimes channel.lock throws a resource deadlock exception but trylock works,
// need to investigate further and review
FileLock lock;
do {
lock = channel.tryLock(liveLockPos, 1, false);
if (lock == null) {
try {
Thread.sleep(500);
} catch (InterruptedException e1) {
//
}
}
if (interrupted) {
interrupted = false;
throw new IOException("Lock was interrupted");
}
} while (lock == null);
return lock;
}
}