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/*
* ============LICENSE_START=======================================================
* feature-distributed-locking
* ================================================================================
* Copyright (C) 2018 AT&T Intellectual Property. 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.
* ============LICENSE_END=========================================================
*/
package org.onap.policy.distributed.locking;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Properties;
import java.util.UUID;
import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbcp2.BasicDataSourceFactory;
import org.onap.policy.common.utils.properties.exception.PropertyException;
import org.onap.policy.drools.core.lock.PolicyResourceLockFeatureApi;
import org.onap.policy.drools.features.PolicyEngineFeatureAPI;
import org.onap.policy.drools.persistence.SystemPersistence;
import org.onap.policy.drools.system.PolicyEngine;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class DistributedLockingFeature implements PolicyEngineFeatureAPI, PolicyResourceLockFeatureApi {
/**
* Logger instance.
*/
private static final Logger logger = LoggerFactory.getLogger(DistributedLockingFeature.class);
/**
* Properties Configuration Name.
*/
public static final String CONFIGURATION_PROPERTIES_NAME = "feature-distributed-locking";
/**
* Properties for locking feature.
*/
private DistributedLockingProperties lockProps;
/**
* Data source used to connect to the DB containing locks.
*/
private BasicDataSource dataSource;
/**
* UUID.
*/
private static final UUID uuid = UUID.randomUUID();
@Override
public int getSequenceNumber() {
return 1000;
}
@Override
public OperResult beforeLock(String resourceId, String owner, int holdSec) {
TargetLock lock = new TargetLock(resourceId, uuid, owner, dataSource);
return (lock.lock(holdSec) ? OperResult.OPER_ACCEPTED : OperResult.OPER_DENIED);
}
@Override
public OperResult beforeRefresh(String resourceId, String owner, int holdSec) {
TargetLock lock = new TargetLock(resourceId, uuid, owner, dataSource);
return (lock.refresh(holdSec) ? OperResult.OPER_ACCEPTED : OperResult.OPER_DENIED);
}
@Override
public OperResult beforeUnlock(String resourceId, String owner) {
TargetLock lock = new TargetLock(resourceId, uuid, owner, dataSource);
return (lock.unlock() ? OperResult.OPER_ACCEPTED : OperResult.OPER_DENIED);
}
@Override
public OperResult beforeIsLockedBy(String resourceId, String owner) {
TargetLock lock = new TargetLock(resourceId, uuid, owner, dataSource);
return (lock.isActive() ? OperResult.OPER_ACCEPTED : OperResult.OPER_DENIED);
}
@Override
public OperResult beforeIsLocked(String resourceId) {
TargetLock lock = new TargetLock(resourceId, uuid, "dummyOwner", dataSource);
return (lock.isLocked() ? OperResult.OPER_ACCEPTED : OperResult.OPER_DENIED);
}
@Override
public boolean afterStart(PolicyEngine engine) {
try {
this.lockProps = new DistributedLockingProperties(
SystemPersistence.manager.getProperties(DistributedLockingFeature.CONFIGURATION_PROPERTIES_NAME));
this.dataSource = makeDataSource();
} catch (PropertyException e) {
logger.error("DistributedLockingFeature feature properies have not been loaded", e);
throw new DistributedLockingFeatureException(e);
} catch (InterruptedException e) {
logger.error("DistributedLockingFeature failed to create data source", e);
Thread.currentThread().interrupt();
throw new DistributedLockingFeatureException(e);
} catch (Exception e) {
logger.error("DistributedLockingFeature failed to create data source", e);
throw new DistributedLockingFeatureException(e);
}
cleanLockTable();
return false;
}
/**
* Make data source.
*
* @return a new, pooled data source
* @throws Exception exception
*/
private BasicDataSource makeDataSource() throws Exception {
Properties props = new Properties();
props.put("driverClassName", lockProps.getDbDriver());
props.put("url", lockProps.getDbUrl());
props.put("username", lockProps.getDbUser());
props.put("password", lockProps.getDbPwd());
props.put("testOnBorrow", "true");
props.put("poolPreparedStatements", "true");
// additional properties are listed in the GenericObjectPool API
return BasicDataSourceFactory.createDataSource(props);
}
/**
* This method kills the heartbeat thread and calls refreshLockTable which removes
* any records from the db where the current host is the owner.
*/
@Override
public boolean beforeShutdown(PolicyEngine engine) {
cleanLockTable();
return false;
}
/**
* This method removes all records owned by the current host from the db.
*/
private void cleanLockTable() {
try (Connection conn = dataSource.getConnection();
PreparedStatement statement = conn.prepareStatement(
"DELETE FROM pooling.locks WHERE host = ? OR expirationTime < now()")
) {
statement.setString(1, uuid.toString());
statement.executeUpdate();
} catch (SQLException e) {
logger.error("error in refreshLockTable()", e);
}
}
}
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