org.apache.activemq.artemis.core.server.impl.InVMNodeManager Maven / Gradle / Ivy
/*
* 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.util.concurrent.Semaphore;
import org.apache.activemq.artemis.api.core.SimpleString;
import org.apache.activemq.artemis.core.server.ActivateCallback;
import org.apache.activemq.artemis.utils.UUIDGenerator;
import static org.apache.activemq.artemis.core.server.impl.InVMNodeManager.State.FAILING_BACK;
import static org.apache.activemq.artemis.core.server.impl.InVMNodeManager.State.LIVE;
import static org.apache.activemq.artemis.core.server.impl.InVMNodeManager.State.NOT_STARTED;
import static org.apache.activemq.artemis.core.server.impl.InVMNodeManager.State.PAUSED;
/**
* NodeManager used to run multiple servers in the same VM.
*
* We use the {@link org.apache.activemq.artemis.core.server.impl.InVMNodeManager} instead of {@link org.apache.activemq.artemis.core.server.impl.FileLockNodeManager} when
* multiple servers are run inside the same VM and File Locks can not be shared in the
* same VM (it would cause a shared lock violation).
*/
public final class InVMNodeManager extends FileBasedNodeManager {
private final Semaphore liveLock;
private final Semaphore backupLock;
public enum State {
LIVE, PAUSED, FAILING_BACK, NOT_STARTED
}
public volatile State state = NOT_STARTED;
public long failoverPause = 0L;
public InVMNodeManager(boolean replicatedBackup) {
this(replicatedBackup, null);
if (replicatedBackup)
throw new RuntimeException("if replicated-backup, we need its journal directory");
}
public InVMNodeManager(boolean replicatedBackup, File directory) {
super(replicatedBackup, directory);
liveLock = new Semaphore(1);
backupLock = new Semaphore(1);
setUUID(UUIDGenerator.getInstance().generateUUID());
}
@Override
public void awaitLiveNode() throws InterruptedException {
do {
while (state == NOT_STARTED) {
Thread.sleep(10);
}
liveLock.acquire();
if (state == PAUSED) {
liveLock.release();
Thread.sleep(10);
} else if (state == FAILING_BACK) {
liveLock.release();
Thread.sleep(10);
} else if (state == LIVE) {
break;
}
}
while (true);
if (failoverPause > 0L) {
Thread.sleep(failoverPause);
}
}
@Override
public void awaitLiveStatus() throws InterruptedException {
while (state != LIVE) {
Thread.sleep(10);
}
}
@Override
public void startBackup() throws InterruptedException {
backupLock.acquire();
}
@Override
public ActivateCallback startLiveNode() throws InterruptedException {
state = FAILING_BACK;
liveLock.acquire();
return new CleaningActivateCallback() {
@Override
public void activationComplete() {
state = LIVE;
}
};
}
@Override
public void pauseLiveServer() {
state = PAUSED;
liveLock.release();
}
@Override
public void crashLiveServer() {
liveLock.release();
}
@Override
public boolean isAwaitingFailback() {
return state == FAILING_BACK;
}
@Override
public boolean isBackupLive() {
return liveLock.availablePermits() == 0;
}
@Override
public void interrupt() {
//
}
@Override
public void releaseBackup() {
backupLock.release();
}
@Override
public SimpleString readNodeId() {
return getNodeId();
}
}