1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
/*
* ============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.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.UUID;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import org.onap.policy.common.utils.properties.exception.PropertyException;
import org.onap.policy.drools.core.lock.LockRequestFuture;
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;
/**
*ScheduledExecutorService for LockHeartbeat
*/
private ScheduledExecutorService scheduledExecutorService;
/**
* UUID
*/
private static final UUID uuid = UUID.randomUUID();
/**
* Reference to Heartbeat
*/
private static Heartbeat heartbeat = null;
@Override
public int getSequenceNumber() {
return 1000;
}
@Override
public Future<Boolean> beforeLock(String resourceId, String owner, Callback callback) {
TargetLock tLock = new TargetLock(resourceId, uuid, owner, lockProps);
return new LockRequestFuture(resourceId, owner, tLock.lock());
}
@Override
public OperResult beforeUnlock(String resourceId, String owner) {
TargetLock tLock = new TargetLock(resourceId, uuid, owner, lockProps);
return(tLock.unlock() ? OperResult.OPER_ACCEPTED : OperResult.OPER_DENIED);
}
@Override
public OperResult beforeIsLockedBy(String resourceId, String owner) {
TargetLock tLock = new TargetLock(resourceId, uuid, owner, lockProps);
return(tLock.isActive() ? OperResult.OPER_ACCEPTED : OperResult.OPER_DENIED);
}
@Override
public OperResult beforeIsLocked(String resourceId) {
TargetLock tLock = new TargetLock(resourceId, uuid, "dummyOwner", lockProps);
return(tLock.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));
} catch (PropertyException e) {
logger.error("DistributedLockingFeature feature properies have not been loaded", e);
throw new DistributedLockingFeatureException(e);
}
long heartbeatInterval = this.lockProps.getHeartBeatIntervalProperty();
cleanLockTable();
heartbeat = new Heartbeat(uuid, lockProps);
this.scheduledExecutorService = Executors.newScheduledThreadPool(1);
this.scheduledExecutorService.scheduleAtFixedRate(heartbeat, heartbeatInterval, heartbeatInterval, TimeUnit.MILLISECONDS);
return false;
}
/**
* 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) {
scheduledExecutorService.shutdown();
cleanLockTable();
return false;
}
/**
* This method removes all records owned by the current host from the db.
*/
private void cleanLockTable() {
try (Connection conn = DriverManager.getConnection(lockProps.getDbUrl(),
lockProps.getDbUser(),
lockProps.getDbPwd());
PreparedStatement statement = conn.prepareStatement("DELETE FROM pooling.locks WHERE host = ? OR expirationTime < ?");
){
statement.setString(1, uuid.toString());
statement.setLong(2, System.currentTimeMillis());
statement.executeUpdate();
} catch (SQLException e) {
logger.error("error in refreshLockTable()", e);
}
}
public static Heartbeat getHeartbeat() {
return heartbeat;
}
}
|
