appc-dispatcher/appc-dispatcher-common/lock-manager-lib/lock-manager-impl/src/main/java/org/openecomp/appc/lockmanager/impl/sql/pessimistic/SqlLockManager.java

   1 /*-
   2  * ============LICENSE_START=======================================================
   3  * openECOMP : APP-C
   4  * ================================================================================
   5  * Copyright (C) 2017 AT&T Intellectual Property. All rights
   6  *                                              reserved.
   7  * ================================================================================
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  * ============LICENSE_END=========================================================
  20  */
  21
  22 package org.openecomp.appc.lockmanager.impl.sql.pessimistic;
  23
  24 import java.sql.Connection;
  25 import java.sql.PreparedStatement;
  26 import java.sql.ResultSet;
  27 import java.sql.SQLException;
  28
  29 import org.openecomp.appc.lockmanager.api.LockException;
  30 import org.openecomp.appc.lockmanager.api.LockRuntimeException;
  31 import org.openecomp.appc.lockmanager.impl.sql.JdbcLockManager;
  32 import org.openecomp.appc.lockmanager.impl.sql.Messages;
  33
  34 abstract class SqlLockManager extends JdbcLockManager {
  35
  36         private static final String SQL_LOAD_LOCK_RECORD = "SELECT * FROM %s WHERE RESOURCE_ID=?";
  37         private static final String SQL_INSERT_LOCK_RECORD = "INSERT INTO %s (RESOURCE_ID, OWNER_ID, UPDATED, TIMEOUT) VALUES (?, ?, ?, ?)";
  38         private static final String SQL_UPDATE_LOCK_RECORD = "UPDATE %s SET OWNER_ID=?, UPDATED=?, TIMEOUT=? WHERE RESOURCE_ID=?";
  39         private static final String SQL_CURRENT_TIMESTAMP = "SELECT CURRENT_TIMESTAMP()";
  40
  41         private String sqlLoadLockRecord;
  42         private String sqlInsertLockRecord;
  43         private String sqlUpdateLockRecord;
  44
  45         @Override
  46         public boolean acquireLock(String resource, String owner) throws LockException {
  47                 return acquireLock(resource, owner, 0);
  48         }
  49
  50         @Override
  51         public boolean acquireLock(String resource, String owner, long timeout) throws LockException {
  52                 if(owner == null) {
  53                         throw new LockRuntimeException(Messages.ERR_NULL_LOCK_OWNER.format(resource));
  54                 }
  55                 boolean res = false;
  56                 Connection connection = openDbConnection();
  57                 try {
  58                         enterCriticalSection(connection, resource);
  59                         try {
  60                                 res = lockResource(connection, resource, owner, timeout);
  61                         } finally {
  62                                 leaveCriticalSection(connection, resource);
  63                         }
  64                 } finally {
  65                         closeDbConnection(connection);
  66                 }
  67                 return res;
  68         }
  69
  70         @Override
  71         public void releaseLock(String resource, String owner) throws LockException {
  72                 Connection connection = openDbConnection();
  73                 try {
  74                         enterCriticalSection(connection, resource);
  75                         try {
  76                                 unlockResource(connection, resource, owner);
  77                         } finally {
  78                                 leaveCriticalSection(connection, resource);
  79                         }
  80                 } finally {
  81                         closeDbConnection(connection);
  82                 }
  83         }
  84
  85         @Override
  86         public boolean isLocked(String resource) {
  87                 Connection connection=openDbConnection();
  88                 try {
  89                         LockRecord lockRecord=loadLockRecord(connection,resource);
  90                         if(lockRecord==null){
  91                                 return false;
  92                         }else{
  93                                 if(lockRecord.getOwner()==null){
  94                                         return false;
  95                                 }else if(isLockExpired(lockRecord, connection)){
  96                                         return false;
  97                                 }else{
  98                                         return true;
  99                                 }
 100                         }
 101                 } catch (SQLException e) {
 102                         throw new LockRuntimeException(Messages.EXP_CHECK_LOCK.format(resource));
 103                 }finally {
 104                         closeDbConnection(connection);
 105                 }
 106         }
 107
 108         private boolean lockResource(Connection connection, String resource, String owner, long timeout) throws LockException {
 109                 try {
 110                         boolean res = false;
 111                         LockRecord lockRecord = loadLockRecord(connection, resource);
 112                         if(lockRecord != null) {
 113                                 // lock record already exists
 114                                 String currentOwner = lockRecord.getOwner();
 115                                 if(currentOwner != null) {
 116                                         if(isLockExpired(lockRecord, connection)) {
 117                                                 currentOwner = null;
 118                                         } else if(!owner.equals(currentOwner)) {
 119                                                 throw new LockException(Messages.ERR_LOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
 120                                         }
 121                                 }
 122                                 // set new owner on the resource lock record
 123                                 updateLockRecord(connection, resource, owner, timeout);
 124                                 if(currentOwner == null) {
 125                                         // no one locked the resource before
 126                                         res = true;
 127                                 }
 128                         } else {
 129                                 // resource record does not exist in lock table => create new record
 130                                 addLockRecord(connection, resource, owner, timeout);
 131                                 res = true;
 132                         }
 133                         return res;
 134                 } catch(SQLException e) {
 135                         throw new LockRuntimeException(Messages.EXP_LOCK.format(resource), e);
 136                 }
 137         }
 138
 139         private void unlockResource(Connection connection, String resource, String owner) throws LockException {
 140                 try {
 141                         LockRecord lockRecord = loadLockRecord(connection, resource);
 142                         if(lockRecord != null) {
 143                                 // check if expired
 144                                 if(isLockExpired(lockRecord, connection)) {
 145                                         // lock is expired => no lock
 146                                         lockRecord = null;
 147                                 }
 148                         }
 149                         if((lockRecord == null) || (lockRecord.getOwner() == null)) {
 150                                 // resource is not locked
 151                                 throw new LockException(Messages.ERR_UNLOCK_NOT_LOCKED.format(resource));
 152                         }
 153                         String currentOwner = lockRecord.getOwner();
 154                         if(!owner.equals(currentOwner)) {
 155                                 throw new LockException(Messages.ERR_UNLOCK_LOCKED_BY_OTHER.format(resource, owner, currentOwner));
 156                         }
 157                         updateLockRecord(connection, resource, null, 0);
 158                         // TODO delete record from table on lock release?
 159 //                      deleteLockRecord(connection, resource);
 160                 } catch(SQLException e) {
 161                         throw new LockRuntimeException(Messages.EXP_UNLOCK.format(resource), e);
 162                 }
 163         }
 164
 165         protected abstract void enterCriticalSection(Connection connection, String resource);
 166
 167         protected abstract void leaveCriticalSection(Connection connection, String resource);
 168
 169         protected LockRecord loadLockRecord(Connection connection, String resource) throws SQLException {
 170                 LockRecord res = null;
 171                 if(sqlLoadLockRecord == null) {
 172                         sqlLoadLockRecord = String.format(SQL_LOAD_LOCK_RECORD, tableName);
 173                 }
 174                 try(PreparedStatement statement = connection.prepareStatement(sqlLoadLockRecord)) {
 175                         statement.setString(1, resource);
 176                         try(ResultSet resultSet = statement.executeQuery()) {
 177                                 if(resultSet.next()) {
 178                                         res = new LockRecord(resource);
 179                                         res.setOwner(resultSet.getString(2));
 180                                         res.setUpdated(resultSet.getLong(3));
 181                                         res.setTimeout(resultSet.getLong(4));
 182                                 }
 183                         }
 184                 }
 185                 return res;
 186         }
 187
 188         protected void addLockRecord(Connection connection, String resource, String owner, long timeout) throws SQLException {
 189                 if(sqlInsertLockRecord == null) {
 190                         sqlInsertLockRecord = String.format(SQL_INSERT_LOCK_RECORD, tableName);
 191                 }
 192                 try(PreparedStatement statement = connection.prepareStatement(sqlInsertLockRecord)) {
 193                         statement.setString(1, resource);
 194                         statement.setString(2, owner);
 195                         statement.setLong(3, getCurrentTime(connection));
 196                         statement.setLong(4, timeout);
 197                         statement.executeUpdate();
 198                 }
 199         }
 200
 201         protected void updateLockRecord(Connection connection, String resource, String owner, long timeout) throws SQLException {
 202                 if(sqlUpdateLockRecord == null) {
 203                         sqlUpdateLockRecord = String.format(SQL_UPDATE_LOCK_RECORD, tableName);
 204                 }
 205                 try(PreparedStatement statement = connection.prepareStatement(sqlUpdateLockRecord)) {
 206                         statement.setString(1, owner);
 207                         statement.setLong(2, getCurrentTime(connection));
 208                         statement.setLong(3, timeout);
 209                         statement.setString(4, resource);
 210                         statement.executeUpdate();
 211                 }
 212         }
 213
 214 //      protected void deleteLockRecord(Connection connection, String resource) throws SQLException {
 215 //              if(sqlDeleteLockRecord == null) {
 216 //                      sqlDeleteLockRecord = String.format(SQL_DELETE_LOCK_RECORD, tableName);
 217 //              }
 218 //              try(PreparedStatement statement = connection.prepareStatement(sqlDeleteLockRecord)) {
 219 //                      statement.setString(1, resource);
 220 //                      statement.executeUpdate();
 221 //              }
 222 //      }
 223
 224         private boolean isLockExpired(LockRecord lockRecord, Connection connection) throws SQLException {
 225                 long timeout = lockRecord.getTimeout();
 226                 if(timeout == 0) {
 227                         return false;
 228                 }
 229                 long updated = lockRecord.getUpdated();
 230                 long now = getCurrentTime(connection);
 231                 long expiration = updated + timeout;
 232                 return (now > expiration);
 233         }
 234
 235         private long getCurrentTime(Connection connection) throws SQLException {
 236                 long res = -1;
 237                 if(connection != null) {
 238                         try(PreparedStatement statement = connection.prepareStatement(SQL_CURRENT_TIMESTAMP)) {
 239                                 try(ResultSet resultSet = statement.executeQuery()) {
 240                                         if(resultSet.next()) {
 241                                                 res = resultSet.getTimestamp(1).getTime();
 242                                         }
 243                                 }
 244                         }
 245                 }
 246                 if(res == -1) {
 247                         res = System.currentTimeMillis();
 248                 }
 249                 return res;
 250         }
 251 }