com.alibaba.wasp.master.OfflineCallback.java Source code

Introduction

Here is the source code for com.alibaba.wasp.master.OfflineCallback.java

Source

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
package com.alibaba.wasp.master;

import com.alibaba.wasp.EntityGroupInfo;
import com.alibaba.wasp.ServerName;
import com.alibaba.wasp.zookeeper.ZooKeeperWatcher;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.zookeeper.AsyncCallback.StringCallback;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;

import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * Callback handler for creating unassigned offline znodes used during bulk
 * assign, async setting entityGroup to offline.
 */
public class OfflineCallback implements StringCallback {
    private final Log LOG = LogFactory.getLog(OfflineCallback.class);
    private final ExistCallback callBack;
    private final ZooKeeperWatcher zkw;
    private final ServerName destination;
    private final AtomicInteger counter;

    OfflineCallback(final ZooKeeperWatcher zkw, final ServerName destination, final AtomicInteger counter,
            final Map<String, Integer> offlineNodesVersions) {
        this.callBack = new ExistCallback(destination, counter, offlineNodesVersions);
        this.destination = destination;
        this.counter = counter;
        this.zkw = zkw;
    }

    @Override
    public void processResult(int rc, String path, Object ctx, String name) {
        if (rc == KeeperException.Code.NODEEXISTS.intValue()) {
            LOG.warn("Node for " + path + " already exists");
        } else if (rc != 0) {
            // This is result code. If non-zero, need to resubmit.
            LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- "
                    + "FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
            this.counter.addAndGet(1);
            return;
        }

        if (LOG.isDebugEnabled()) {
            LOG.debug("rs=" + ctx + ", server=" + destination);
        }
        // Async exists to set a watcher so we'll get triggered when
        // unassigned node changes.
        ZooKeeper zk = this.zkw.getRecoverableZooKeeper().getZooKeeper();
        zk.exists(path, this.zkw, callBack, ctx);
    }

    /**
     * Callback handler for the exists call that sets watcher on unassigned
     * znodes. Used during bulk assign on startup.
     */
    static class ExistCallback implements StatCallback {
        private final Log LOG = LogFactory.getLog(ExistCallback.class);
        private final Map<String, Integer> offlineNodesVersions;
        private final AtomicInteger counter;
        private ServerName destination;

        ExistCallback(final ServerName destination, final AtomicInteger counter,
                final Map<String, Integer> offlineNodesVersions) {
            this.offlineNodesVersions = offlineNodesVersions;
            this.destination = destination;
            this.counter = counter;
        }

        @Override
        public void processResult(int rc, String path, Object ctx, Stat stat) {
            if (rc != 0) {
                // This is result code. If non-zero, need to resubmit.
                LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- "
                        + "FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
                this.counter.addAndGet(1);
                return;
            }

            if (LOG.isDebugEnabled()) {
                LOG.debug("rs=" + ctx + ", server=" + destination);
            }
            EntityGroupInfo entityGroup = ((EntityGroupState) ctx).getEntityGroup();
            offlineNodesVersions.put(entityGroup.getEncodedName(), Integer.valueOf(stat.getVersion()));
            this.counter.addAndGet(1);
        }
    }

}