2 * ============LICENSE_START==========================================
4 * ===================================================================
5 * Copyright (c) 2017 AT&T Intellectual Property
6 * Modifications Copyright (C) 2018 IBM.
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
12 * http://www.apache.org/licenses/LICENSE-2.0
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.
20 * ============LICENSE_END=============================================
21 * ====================================================================
23 package org.onap.music.lockingservice;
25 import org.apache.zookeeper.CreateMode;
26 import org.apache.zookeeper.KeeperException;
27 import org.apache.zookeeper.ZooDefs;
28 import org.apache.zookeeper.ZooKeeper;
29 import org.apache.zookeeper.data.ACL;
30 import org.apache.zookeeper.data.Stat;
31 import org.onap.music.eelf.logging.EELFLoggerDelegate;
32 import org.onap.music.eelf.logging.format.AppMessages;
33 import org.onap.music.eelf.logging.format.ErrorSeverity;
34 import org.onap.music.eelf.logging.format.ErrorTypes;
35 import org.onap.music.lockingservice.ZooKeeperOperation;
36 import java.util.List;
37 import java.util.concurrent.atomic.AtomicBoolean;
40 * A base class for protocol implementations which provides a number of higher level helper methods
41 * for working with ZooKeeper along with retrying synchronous operations if the connection to
42 * ZooKeeper closes such as {@link #retryOperation(ZooKeeperOperation)}
45 class ProtocolSupport {
46 private EELFLoggerDelegate logger = EELFLoggerDelegate.getLogger(ProtocolSupport.class);
48 protected ZooKeeper zookeeper;
49 private AtomicBoolean closed = new AtomicBoolean(false);
50 private long retryDelay = 500L;
51 private int retryCount = 10;
52 private List<ACL> acl = ZooDefs.Ids.OPEN_ACL_UNSAFE;
55 * Closes this strategy and releases any ZooKeeper resources; but keeps the ZooKeeper instance
59 if (closed.compareAndSet(false, true)) {
65 * return zookeeper client instance
67 * @return zookeeper client instance
69 public ZooKeeper getZookeeper() {
74 * return the acl its using
78 public List<ACL> getAcl() {
85 * @param acl the acl to set to
87 public void setAcl(List<ACL> acl) {
92 * get the retry delay in milliseconds
94 * @return the retry delay
96 public long getRetryDelay() {
101 * Sets the time waited between retry delays
103 * @param retryDelay the retry delay
105 public void setRetryDelay(long retryDelay) {
106 this.retryDelay = retryDelay;
110 * Allow derived classes to perform some custom closing operations to release resources
112 protected void doClose() {
113 throw new UnsupportedOperationException();
118 * Perform the given operation, retrying if the connection fails
120 * @return object. it needs to be cast to the callee's expected return type.
121 * @param operation FILL IN
122 * @throws KeeperException FILL IN
123 * @throws InterruptedException FILL IN
125 protected Object retryOperation(ZooKeeperOperation operation)
126 throws KeeperException, InterruptedException {
127 KeeperException exception = null;
128 for (int i = 0; i < retryCount; i++) {
130 return operation.execute();
131 } catch (KeeperException.SessionExpiredException e) {
132 logger.error(EELFLoggerDelegate.errorLogger, e,AppMessages.SESSIONEXPIRED+" for: " + zookeeper + " so reconnecting due to: " + e, ErrorSeverity.ERROR, ErrorTypes.SESSIONEXPIRED);
134 } catch (KeeperException.ConnectionLossException e) {
135 if (exception == null) {
138 logger.error(EELFLoggerDelegate.errorLogger, e,AppMessages.CONNCECTIVITYERROR, ErrorSeverity.ERROR, ErrorTypes.SESSIONEXPIRED);
139 logger.error(EELFLoggerDelegate.errorLogger, e,"Attempt " + i + " failed with connection loss so attempting to reconnect: " + e);
144 if(exception == null)
146 throw new NullPointerException();
154 * Ensures that the given path exists with no data, the current ACL and no flags
156 * @param path the lock path
158 protected void ensurePathExists(String path) {
159 ensureExists(path, null, acl, CreateMode.PERSISTENT);
163 * Ensures that the given path exists with the given data, ACL and flags
165 * @param path the lock path
166 * @param data the data
167 * @param acl list of ACLs applying to the path
168 * @param flags create mode flags
170 protected void ensureExists(final String path, final byte[] data, final List<ACL> acl,
171 final CreateMode flags) {
173 retryOperation(new ZooKeeperOperation() {
174 public boolean execute() throws KeeperException, InterruptedException {
175 Stat stat = zookeeper.exists(path, false);
179 zookeeper.create(path, data, acl, flags);
183 } catch (KeeperException e) {
184 logger.error(EELFLoggerDelegate.errorLogger, e,AppMessages.KEEPERERROR, ErrorSeverity.ERROR, ErrorTypes.LOCKINGERROR);
185 } catch (InterruptedException e) {
186 logger.error(EELFLoggerDelegate.errorLogger, e,AppMessages.EXECUTIONINTERRUPTED, ErrorSeverity.ERROR, ErrorTypes.LOCKINGERROR);
192 * Returns true if this protocol has been closed
194 * @return true if this protocol is closed
196 protected boolean isClosed() {
201 * Performs a retry delay if this is not the first attempt
203 * @param attemptCount the number of the attempts performed so far
205 protected void retryDelay(int attemptCount) {
206 if (attemptCount > 0) {
208 Thread.sleep(attemptCount * retryDelay);
209 } catch (InterruptedException e) {
210 logger.error(EELFLoggerDelegate.errorLogger, e,AppMessages.EXECUTIONINTERRUPTED, ErrorSeverity.ERROR, ErrorTypes.GENERALSERVICEERROR);
211 logger.error(EELFLoggerDelegate.errorLogger, e,"Thread failed to sleep: " + e);
212 Thread.currentThread().interrupt();