001/*
002 * (C) Copyright 2014 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Florent Guillaume
018 */
019package org.nuxeo.ecm.core.redis.contribs;
020
021import java.io.IOException;
022import java.util.Arrays;
023import java.util.Calendar;
024
025import org.apache.commons.lang.StringUtils;
026import org.apache.commons.logging.Log;
027import org.apache.commons.logging.LogFactory;
028import org.nuxeo.ecm.core.api.Lock;
029import org.nuxeo.ecm.core.api.NuxeoException;
030import org.nuxeo.ecm.core.model.LockManager;
031import org.nuxeo.ecm.core.redis.RedisAdmin;
032import org.nuxeo.ecm.core.redis.RedisCallable;
033import org.nuxeo.ecm.core.redis.RedisExecutor;
034import org.nuxeo.runtime.api.Framework;
035
036import redis.clients.jedis.Jedis;
037
038/**
039 * Redis-based lock manager.
040 *
041 * @since 6.0
042 */
043public class RedisLockManager implements LockManager {
044
045    @SuppressWarnings("unused")
046    private static final Log log = LogFactory.getLog(RedisLockManager.class);
047
048    protected final String redisNamespace;
049
050    protected final String repositoryName;
051
052    protected RedisExecutor redisExecutor;
053
054    protected String prefix;
055
056    protected String scriptSetSha;
057
058    protected String scriptRemoveSha;
059
060    protected RedisAdmin redisAdmin;
061
062    /**
063     * Creates a lock manager for the given repository.
064     * <p>
065     * {@link #close} must be called when done with the lock manager.
066     */
067    public RedisLockManager(String repositoryName) {
068        this.repositoryName = repositoryName;
069        redisExecutor = Framework.getService(RedisExecutor.class);
070        redisAdmin = Framework.getService(RedisAdmin.class);
071        redisNamespace = redisAdmin.namespace("lock", repositoryName);
072        loadScripts();
073    }
074
075    public void loadScripts() {
076        try {
077            scriptSetSha = redisAdmin.load("org.nuxeo.ecm.core.redis", "set-lock");
078            scriptRemoveSha = redisAdmin.load("org.nuxeo.ecm.core.redis", "remove-lock");
079        } catch (IOException cause) {
080            throw new NuxeoException("Cannot load lock scripts in redis", cause);
081        }
082    }
083
084    protected String stringFromLock(Lock lock) {
085        if (lock == null) {
086            throw new NullPointerException("null lock");
087        }
088        return lock.getOwner() + ":" + lock.getCreated().getTimeInMillis();
089    }
090
091    protected Lock lockFromString(String lockString) {
092        if (lockString == null) {
093            return null;
094        }
095        String[] split = lockString.split(":");
096        if (split.length != 2 || !StringUtils.isNumeric(split[1])) {
097            throw new IllegalArgumentException("Invalid Redis lock : " + lockString + ", should be " + redisNamespace
098                    + "<id>");
099        }
100        Calendar created = Calendar.getInstance();
101        created.setTimeInMillis(Long.parseLong(split[1]));
102        return new Lock(split[0], created);
103    }
104
105    @Override
106    public Lock getLock(final String id) {
107        return redisExecutor.execute(new RedisCallable<Lock>() {
108            @Override
109            public Lock call(Jedis jedis) {
110                String lockString = jedis.get(redisNamespace + id);
111                return lockFromString(lockString);
112            }
113        });
114    }
115
116    @Override
117    public Lock setLock(final String id, final Lock lock) {
118        return redisExecutor.execute(new RedisCallable<Lock>() {
119            @Override
120            public Lock call(Jedis jedis) {
121                String lockString = (String) jedis.evalsha(scriptSetSha, Arrays.asList(redisNamespace + id),
122                        Arrays.asList(stringFromLock(lock)));
123                return lockFromString(lockString); // existing lock
124            }
125        });
126    }
127
128    @Override
129    public Lock removeLock(final String id, final String owner) {
130        return redisExecutor.execute(new RedisCallable<Lock>() {
131            @Override
132            public Lock call(Jedis jedis) {
133                String lockString = (String) jedis.evalsha(scriptRemoveSha, Arrays.asList(redisNamespace + id),
134                        Arrays.asList(owner == null ? "" : owner));
135                Lock lock = lockFromString(lockString);
136                if (lock != null && owner != null && !owner.equals(lock.getOwner())) {
137                    lock = new Lock(lock, true); // failed removal
138                }
139                return lock;
140            }
141        });
142    }
143
144    @Override
145    public void closeLockManager() {
146    }
147
148    @Override
149    public void clearLockManagerCaches() {
150    }
151
152    @Override
153    public String toString() {
154        return getClass().getSimpleName() + '(' + repositoryName + ')';
155    }
156
157}