2 * ============LICENSE_START==========================================
4 * ===================================================================
5 * Copyright (c) 2017 AT&T Intellectual Property
6 * ===================================================================
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
19 * ============LICENSE_END=============================================
20 * ====================================================================
22 package org.onap.music.lockingservice;
24 import org.apache.zookeeper.CreateMode;
25 import org.apache.zookeeper.KeeperException;
26 import org.apache.zookeeper.ZooDefs;
27 import org.apache.zookeeper.ZooKeeper;
28 import org.apache.zookeeper.data.ACL;
29 import org.apache.zookeeper.data.Stat;
30 import org.onap.music.eelf.logging.EELFLoggerDelegate;
31 import org.onap.music.eelf.logging.format.AppMessages;
32 import org.onap.music.eelf.logging.format.ErrorSeverity;
33 import org.onap.music.eelf.logging.format.ErrorTypes;
34 import org.onap.music.lockingservice.ZooKeeperOperation;
35 import java.util.List;
36 import java.util.concurrent.atomic.AtomicBoolean;
39 * A base class for protocol implementations which provides a number of higher level helper methods
40 * for working with ZooKeeper along with retrying synchronous operations if the connection to
41 * ZooKeeper closes such as {@link #retryOperation(ZooKeeperOperation)}
44 class ProtocolSupport {
45 private EELFLoggerDelegate logger = EELFLoggerDelegate.getLogger(ProtocolSupport.class);
47 protected ZooKeeper zookeeper;
48 private AtomicBoolean closed = new AtomicBoolean(false);
49 private long retryDelay = 500L;
50 private int retryCount = 10;
51 private List<ACL> acl = ZooDefs.Ids.OPEN_ACL_UNSAFE;
54 * Closes this strategy and releases any ZooKeeper resources; but keeps the ZooKeeper instance
58 if (closed.compareAndSet(false, true)) {
64 * return zookeeper client instance
66 * @return zookeeper client instance
68 public ZooKeeper getZookeeper() {
73 * return the acl its using
77 public List<ACL> getAcl() {
84 * @param acl the acl to set to
86 public void setAcl(List<ACL> acl) {
91 * get the retry delay in milliseconds
93 * @return the retry delay
95 public long getRetryDelay() {
100 * Sets the time waited between retry delays
102 * @param retryDelay the retry delay
104 public void setRetryDelay(long retryDelay) {
105 this.retryDelay = retryDelay;
109 * Allow derived classes to perform some custom closing operations to release resources
111 protected void doClose() {
112 throw new UnsupportedOperationException();
117 * Perform the given operation, retrying if the connection fails
119 * @return object. it needs to be cast to the callee's expected return type.
120 * @param operation FILL IN
121 * @throws KeeperException FILL IN
122 * @throws InterruptedException FILL IN
124 protected Object retryOperation(ZooKeeperOperation operation)
125 throws KeeperException, InterruptedException {
126 KeeperException exception = null;
127 for (int i = 0; i < retryCount; i++) {
129 return operation.execute();
130 } catch (KeeperException.SessionExpiredException e) {
131 logger.error(EELFLoggerDelegate.errorLogger, e.getMessage(),AppMessages.SESSIONEXPIRED+" for: " + zookeeper + " so reconnecting due to: " + e, ErrorSeverity.ERROR, ErrorTypes.SESSIONEXPIRED);
133 } catch (KeeperException.ConnectionLossException e) {
134 if (exception == null) {
137 logger.error(EELFLoggerDelegate.errorLogger, e.getMessage(),AppMessages.CONNCECTIVITYERROR, ErrorSeverity.ERROR, ErrorTypes.SESSIONEXPIRED);
138 logger.error(EELFLoggerDelegate.errorLogger, e.getMessage(),"Attempt " + i + " failed with connection loss so attempting to reconnect: " + e);
147 * Ensures that the given path exists with no data, the current ACL and no flags
149 * @param path the lock path
151 protected void ensurePathExists(String path) {
152 ensureExists(path, null, acl, CreateMode.PERSISTENT);
156 * Ensures that the given path exists with the given data, ACL and flags
158 * @param path the lock path
159 * @param data the data
160 * @param acl list of ACLs applying to the path
161 * @param flags create mode flags
163 protected void ensureExists(final String path, final byte[] data, final List<ACL> acl,
164 final CreateMode flags) {
166 retryOperation(new ZooKeeperOperation() {
167 public boolean execute() throws KeeperException, InterruptedException {
168 Stat stat = zookeeper.exists(path, false);
172 zookeeper.create(path, data, acl, flags);
176 } catch (KeeperException e) {
177 logger.error("Error", e);
178 logger.error(EELFLoggerDelegate.errorLogger, e.getMessage(),AppMessages.KEEPERERROR, ErrorSeverity.ERROR, ErrorTypes.LOCKINGERROR);
179 } catch (InterruptedException e) {
180 logger.error("Error", e);
181 logger.error(EELFLoggerDelegate.errorLogger, e.getMessage(),AppMessages.EXECUTIONINTERRUPTED, ErrorSeverity.ERROR, ErrorTypes.LOCKINGERROR);
186 * Returns true if this protocol has been closed
188 * @return true if this protocol is closed
190 protected boolean isClosed() {
195 * Performs a retry delay if this is not the first attempt
197 * @param attemptCount the number of the attempts performed so far
199 protected void retryDelay(int attemptCount) {
200 if (attemptCount > 0) {
202 Thread.sleep(attemptCount * retryDelay);
203 } catch (InterruptedException e) {
204 logger.error(EELFLoggerDelegate.errorLogger, e.getMessage(),AppMessages.EXECUTIONINTERRUPTED, ErrorSeverity.ERROR, ErrorTypes.GENERALSERVICEERROR);
205 logger.error(EELFLoggerDelegate.errorLogger, e.getMessage(),"Thread failed to sleep: " + e);
206 Thread.currentThread().interrupt();