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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2016-2018 Ericsson. All rights reserved.
* ================================================================================
* 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.
*
* SPDX-License-Identifier: Apache-2.0
* ============LICENSE_END=========================================================
*/
package org.onap.policy.apex.plugins.context.locking.curator;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReadWriteLock;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.framework.state.ConnectionStateListener;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.curator.utils.CloseableUtils;
import org.apache.zookeeper.CreateMode;
import org.onap.policy.apex.context.ContextException;
import org.onap.policy.apex.context.impl.locking.AbstractLockManager;
import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
import org.onap.policy.common.parameters.ParameterService;
import org.slf4j.ext.XLogger;
import org.slf4j.ext.XLoggerFactory;
/**
* The Class CuratorLockManager manages the Curator interface towards Zookeeper for administering the Apex Context Album
* instance locks..
*/
public class CuratorLockManager extends AbstractLockManager {
// Logger for this class
private static final XLogger LOGGER = XLoggerFactory.getXLogger(CuratorLockManager.class);
// The Curator framework used for locking
private CuratorFramework curatorFramework;
// The address of the Zookeeper server
private String curatorZookeeperAddress;
/**
* Constructor, set up a lock manager that uses Curator locking.
*
* @throws ContextException On errors connecting to Curator
*/
public CuratorLockManager() throws ContextException {
LOGGER.entry("CuratorLockManager(): setting up the Curator lock manager . . .");
LOGGER.exit("CuratorLockManager(): Curator lock manager set up");
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.context.impl.locking.AbstractLockManager#init(org.onap.policy.apex. model.
* basicmodel.concepts.AxArtifactKey)
*/
@Override
public void init(final AxArtifactKey key) throws ContextException {
LOGGER.entry("init(" + key + ")");
super.init(key);
// Get the lock manager parameters
final CuratorLockManagerParameters lockParameters = ParameterService
.get(CuratorLockManagerParameters.class.getSimpleName());
// Check if the curator address has been set
curatorZookeeperAddress = lockParameters.getZookeeperAddress();
if (curatorZookeeperAddress == null || curatorZookeeperAddress.trim().length() == 0) {
String message = "could not set up Curator locking, "
+ "check if the curator Zookeeper address parameter is set correctly";
LOGGER.warn(message);
throw new ContextException(message);
}
// Set up the curator framework we'll use
curatorFramework = CuratorFrameworkFactory.builder().connectString(curatorZookeeperAddress)
.retryPolicy(new ExponentialBackoffRetry(lockParameters.getZookeeperConnectSleepTime(),
lockParameters.getZookeeperContextRetries()))
.build();
// Listen for changes on the Curator connection
curatorFramework.getConnectionStateListenable().addListener(new CuratorManagerConnectionStateListener());
// Start the framework and specify Ephemeral nodes
curatorFramework.start();
// Wait for the connection to be made
try {
curatorFramework.blockUntilConnected(
lockParameters.getZookeeperConnectSleepTime() * lockParameters.getZookeeperContextRetries(),
TimeUnit.MILLISECONDS);
} catch (final InterruptedException e) {
// restore the interrupt status
Thread.currentThread().interrupt();
String message = "error connecting to Zookeeper server at \"" + curatorZookeeperAddress
+ "\", wait for connection timed out";
LOGGER.warn(message);
throw new ContextException(message);
}
if (!curatorFramework.getZookeeperClient().isConnected()) {
String message = "could not connect to Zookeeper server at \"" + curatorZookeeperAddress
+ "\", see error log for details";
LOGGER.warn(message);
throw new ContextException(message);
}
// We'll use Ephemeral nodes for locks on the Zookeeper server
curatorFramework.create().withMode(CreateMode.EPHEMERAL_SEQUENTIAL);
LOGGER.exit("init(" + key + "," + lockParameters + ")");
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.core.context.impl.locking.AbstractLockManager#getReentrantReadWriteLock(
* java.lang.String)
*/
@Override
public ReadWriteLock getReentrantReadWriteLock(final String lockId) throws ContextException {
// Check if the framework is active
if (curatorFramework != null && curatorFramework.getZookeeperClient().isConnected()) {
return new CuratorReentrantReadWriteLock(curatorFramework, "/" + lockId);
} else {
throw new ContextException("creation of lock using Zookeeper server at \"" + curatorZookeeperAddress
+ "\", failed, see error log for details");
}
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.core.context.LockManager#shutdown()
*/
@Override
public void shutdown() {
if (curatorFramework == null) {
return;
}
CloseableUtils.closeQuietly(curatorFramework);
curatorFramework = null;
}
/**
* This class is a callback class for state changes on the curator to Zookeeper connection.
*/
private class CuratorManagerConnectionStateListener implements ConnectionStateListener {
/*
* (non-Javadoc)
*
* @see org.apache.curator.framework.state.ConnectionStateListener#stateChanged(org.apache.
* curator.framework.CuratorFramework, org.apache.curator.framework.state.ConnectionState)
*/
@Override
public void stateChanged(final CuratorFramework incomngCuratorFramework, final ConnectionState newState) {
// Is the state changed for this curator framework?
if (!incomngCuratorFramework.equals(curatorFramework)) {
return;
}
LOGGER.info("curator state of client \"{}\" connected to \"{}\" changed to {}", curatorFramework,
curatorZookeeperAddress, newState);
if (newState != ConnectionState.CONNECTED) {
shutdown();
}
}
}
}
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