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/*
* ============LICENSE_START==========================================
* org.onap.music
* ===================================================================
* Copyright (c) 2017 AT&T Intellectual Property
* ===================================================================
* 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.music.lockingservice.cassandra;
import java.util.ArrayList;
import java.util.List;
import org.onap.music.datastore.MusicDataStore;
import org.onap.music.datastore.PreparedQueryObject;
import org.onap.music.eelf.logging.EELFLoggerDelegate;
import org.onap.music.exceptions.MusicQueryException;
import org.onap.music.exceptions.MusicServiceException;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
/*
* This is the lock store that is built on top of Cassandra that is used by MUSIC to maintain lock state.
*/
public class CassaLockStore {
private EELFLoggerDelegate logger = EELFLoggerDelegate.getLogger(CassaLockStore.class);
private static String table_prepend_name = "lockQ_";
public class LockObject{
public String lockRef;
public String createTime;
public String acquireTime;
public LockObject(String lockRef, String createTime, String acquireTime) {
this.lockRef = lockRef;
this.acquireTime = acquireTime;
this.createTime = createTime;
}
}
MusicDataStore dsHandle;
public CassaLockStore() {
dsHandle = new MusicDataStore();
}
public CassaLockStore(MusicDataStore dsHandle) {
this.dsHandle=dsHandle;
}
/**
*
* This method creates a shadow locking table for every main table in Cassandra. This table tracks all information regarding locks.
* @param keyspace of the application.
* @param table of the application.
* @return true if the operation was successful.
* @throws MusicServiceException
* @throws MusicQueryException
*/
public boolean createLockQueue(String keyspace, String table) throws MusicServiceException, MusicQueryException {
logger.info(EELFLoggerDelegate.applicationLogger,
"Create lock queue/table for " + keyspace+"."+table);
table = table_prepend_name+table;
String tabQuery = "CREATE TABLE IF NOT EXISTS "+keyspace+"."+table
+ " ( key text, lockReference bigint, createTime text, acquireTime text, guard bigint static, PRIMARY KEY ((key), lockReference) ) "
+ "WITH CLUSTERING ORDER BY (lockReference ASC);";
PreparedQueryObject queryObject = new PreparedQueryObject();
queryObject.appendQueryString(tabQuery);
boolean result;
result = dsHandle.executePut(queryObject, "eventual");
return result;
}
/**
* This method creates a lock reference for each invocation. The lock references are monotonically increasing timestamps.
* @param keyspace of the locks.
* @param table of the locks.
* @param lockName is the primary key of the lock table
* @return the UUID lock reference.
* @throws MusicServiceException
* @throws MusicQueryException
*/
public String genLockRefandEnQueue(String keyspace, String table, String lockName) throws MusicServiceException, MusicQueryException {
logger.info(EELFLoggerDelegate.applicationLogger,
"Create lock reference for " + keyspace + "." + table + "." + lockName);
String lockTable ="";
lockTable = table_prepend_name+table;
PreparedQueryObject queryObject = new PreparedQueryObject();
String selectQuery = "SELECT guard FROM " + keyspace + "." + lockTable + " WHERE key=?;";
queryObject.addValue(lockName);
queryObject.appendQueryString(selectQuery);
ResultSet gqResult = dsHandle.executeOneConsistencyGet(queryObject);
List<Row> latestGuardRow = gqResult.all();
long prevGuard = 0;
long lockRef = 1;
if (latestGuardRow.size() > 0) {
prevGuard = latestGuardRow.get(0).getLong(0);
lockRef = prevGuard + 1;
}
long lockEpochMillis = System.currentTimeMillis();
// System.out.println("guard(" + lockName + "): " + prevGuard + "->" + lockRef);
logger.info(EELFLoggerDelegate.applicationLogger,
"Created lock reference for " + keyspace + "." + lockTable + "." + lockName + ":" + lockRef);
queryObject = new PreparedQueryObject();
String insQuery = "BEGIN BATCH" +
" UPDATE " + keyspace + "." + lockTable +
" SET guard=? WHERE key=? IF guard = " + (prevGuard == 0 ? "NULL" : "?") +";" +
" INSERT INTO " + keyspace + "." + lockTable +
"(key, lockReference, createTime, acquireTime) VALUES (?,?,?,?) IF NOT EXISTS; APPLY BATCH;";
queryObject.addValue(lockRef);
queryObject.addValue(lockName);
if (prevGuard != 0)
queryObject.addValue(prevGuard);
queryObject.addValue(lockName);
queryObject.addValue(lockRef);
queryObject.addValue(String.valueOf(lockEpochMillis));
queryObject.addValue("0");
queryObject.appendQueryString(insQuery);
boolean pResult = dsHandle.executePut(queryObject, "critical");
return "$"+keyspace+"."+table+"."+lockName+"$"+String.valueOf(lockRef);
}
/**
* Returns a result set containing the list of clients waiting for a particular lock
* @param keyspace
* @param table
* @param key
* @return list of lockrefs in the queue
* @throws MusicServiceException
* @throws MusicQueryException
*/
public List<String> getLockQueue(String keyspace, String table, String key)
throws MusicServiceException, MusicQueryException {
logger.info(EELFLoggerDelegate.applicationLogger,
"Getting the queue for " + keyspace+"."+table+"."+key);
table = table_prepend_name+table;
String selectQuery = "select * from " + keyspace + "." + table + " where key='" + key + "';";
PreparedQueryObject queryObject = new PreparedQueryObject();
queryObject.appendQueryString(selectQuery);
ResultSet rs = dsHandle.executeOneConsistencyGet(queryObject);
ArrayList<String> lockQueue = new ArrayList<>();
for (Row row: rs) {
lockQueue.add(Long.toString(row.getLong("lockReference")));
}
return lockQueue;
}
/**
* Returns a result set containing the list of clients waiting for a particular lock
* @param keyspace
* @param table
* @param key
* @return size of lockrefs queue
* @throws MusicServiceException
* @throws MusicQueryException
*/
public long getLockQueueSize(String keyspace, String table, String key)
throws MusicServiceException, MusicQueryException {
logger.info(EELFLoggerDelegate.applicationLogger,
"Getting the queue size for " + keyspace+"."+table+"."+key);
table = table_prepend_name+table;
String selectQuery = "select count(*) from " + keyspace + "." + table + " where key='" + key + "';";
PreparedQueryObject queryObject = new PreparedQueryObject();
queryObject.appendQueryString(selectQuery);
ResultSet rs = dsHandle.executeOneConsistencyGet(queryObject);
return rs.one().getLong("count");
}
/**
* This method returns the top of lock table/queue for the key.
* @param keyspace of the application.
* @param table of the application.
* @param key is the primary key of the application table
* @return the UUID lock reference.
* @throws MusicServiceException
* @throws MusicQueryException
*/
public LockObject peekLockQueue(String keyspace, String table, String key) throws MusicServiceException, MusicQueryException{
logger.info(EELFLoggerDelegate.applicationLogger,
"Peek in lock table for " + keyspace+"."+table+"."+key);
table = table_prepend_name+table;
String selectQuery = "select * from "+keyspace+"."+table+" where key='"+key+"' LIMIT 1;";
PreparedQueryObject queryObject = new PreparedQueryObject();
queryObject.appendQueryString(selectQuery);
ResultSet results = dsHandle.executeOneConsistencyGet(queryObject);
Row row = results.one();
String lockReference = "" + row.getLong("lockReference");
String createTime = row.getString("createTime");
String acquireTime = row.getString("acquireTime");
return new LockObject(lockReference, createTime,acquireTime);
}
/**
* This method removes the lock ref from the lock table/queue for the key.
* @param keyspace of the application.
* @param table of the application.
* @param key is the primary key of the application table
* @param lockReference the lock reference that needs to be dequeued.
* @throws MusicServiceException
* @throws MusicQueryException
*/
public void deQueueLockRef(String keyspace, String table, String key, String lockReference) throws MusicServiceException, MusicQueryException{
table = table_prepend_name+table;
PreparedQueryObject queryObject = new PreparedQueryObject();
Long lockReferenceL = Long.parseLong(lockReference.substring(lockReference.lastIndexOf("$")+1));
String deleteQuery = "delete from "+keyspace+"."+table+" where key='"+key+"' AND lockReference ="+lockReferenceL+" IF EXISTS;";
queryObject.appendQueryString(deleteQuery);
dsHandle.executePut(queryObject, "critical");
}
public void updateLockAcquireTime(String keyspace, String table, String key, String lockReference) throws MusicServiceException, MusicQueryException{
table = table_prepend_name+table;
PreparedQueryObject queryObject = new PreparedQueryObject();
Long lockReferenceL = Long.parseLong(lockReference);
String updateQuery = "update "+keyspace+"."+table+" set acquireTime='"+ System.currentTimeMillis()+"' where key='"+key+"' AND lockReference = "+lockReferenceL+" IF EXISTS;";
queryObject.appendQueryString(updateQuery);
dsHandle.executePut(queryObject, "eventual");
}
}
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