/*
* Copyright (C) 2010-2101 Alibaba Group Holding Limited.
*
* 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.
*/
package com.alibaba.otter.shared.arbitrate.impl.setl.zookeeper;
import org.I0Itec.zkclient.exception.ZkException;
import org.I0Itec.zkclient.exception.ZkNoNodeException;
import org.I0Itec.zkclient.exception.ZkNodeExistsException;
import org.apache.zookeeper.CreateMode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.otter.shared.arbitrate.exception.ArbitrateException;
import com.alibaba.otter.shared.arbitrate.impl.config.ArbitrateConfigUtils;
import com.alibaba.otter.shared.arbitrate.impl.setl.ArbitrateFactory;
import com.alibaba.otter.shared.arbitrate.impl.setl.TransformArbitrateEvent;
import com.alibaba.otter.shared.arbitrate.impl.setl.helper.StagePathUtils;
import com.alibaba.otter.shared.arbitrate.impl.setl.monitor.PermitMonitor;
import com.alibaba.otter.shared.arbitrate.impl.setl.zookeeper.monitor.TransformStageListener;
import com.alibaba.otter.shared.arbitrate.impl.zookeeper.ZooKeeperClient;
import com.alibaba.otter.shared.arbitrate.model.EtlEventData;
import com.alibaba.otter.shared.common.model.config.channel.ChannelStatus;
import com.alibaba.otter.shared.common.utils.JsonUtils;
import com.alibaba.otter.shared.common.utils.zookeeper.ZkClientx;
/**
* 关注extracted节点，创建transformed节点
*
* @author jianghang 2011-8-9 下午05:10:50
*/
public class TransformZooKeeperArbitrateEvent implements TransformArbitrateEvent {
private static final Logger logger = LoggerFactory.getLogger(TransformZooKeeperArbitrateEvent.class);
private ZkClientx zookeeper = ZooKeeperClient.getInstance();
/**
* <pre>
* 算法:
* 1. 检查当前的Permit，阻塞等待其授权(解决Channel的pause状态处理)
* 2. 开始阻塞获取符合条件的processId
* 3. 检查当前的即时Permit状态 (在阻塞获取processId过程会出现一些error信号,process节点会被删除)
* 4. 获取Select传递的EventData数据，添加next node信息后直接返回
* </pre>
*
* @return
*/
public EtlEventData await(Long pipelineId) throws InterruptedException {
Assert.notNull(pipelineId);
PermitMonitor permitMonitor = ArbitrateFactory.getInstance(pipelineId, PermitMonitor.class);
permitMonitor.waitForPermit();// 阻塞等待授权
TransformStageListener transformStageListener = ArbitrateFactory.getInstance(pipelineId,
TransformStageListener.class);
Long processId = transformStageListener.waitForProcess(); // 符合条件的processId
ChannelStatus status = permitMonitor.getChannelPermit();
if (status.isStart()) {// 即时查询一下当前的状态，状态随时可能会变
// 根据pipelineId+processId构造对应的path
String path = StagePathUtils.getExtractStage(pipelineId, processId);
try {
byte[] data = zookeeper.readData(path);
EtlEventData eventData = JsonUtils.unmarshalFromByte(data, EtlEventData.class);
eventData.setNextNid(ArbitrateConfigUtils.getCurrentNid());// 下一个节点信息即为自己
return eventData;// 只有这一条路返回
} catch (ZkNoNodeException e) {
logger.error("pipeline[{}] processId[{}] is invalid , retry again", pipelineId, processId);
return await(pipelineId);// /出现节点不存在，说明出现了error情况,递归调用重新获取一次
} catch (ZkException e) {
throw new ArbitrateException("transform_await", e.getMessage(), e);
}
} else {
logger.info("pipelineId[{}] transform ignore processId[{}] by status[{}]", new Object[] { pipelineId,
processId, status });
return await(pipelineId);// 递归调用
}
}
/**
* <pre>
* 算法:
* 1. 创建对应的transformed节点,标志transform已完成
* </pre>
*
* @param pipelineId 同步流id
*/
public void single(EtlEventData data) {
Assert.notNull(data);
String path = StagePathUtils.getTransformStage(data.getPipelineId(), data.getProcessId());
data.setCurrNid(ArbitrateConfigUtils.getCurrentNid());
// 序列化
byte[] bytes = JsonUtils.marshalToByte(data, SerializerFeature.WriteClassName);
try {
zookeeper.create(path, bytes, CreateMode.PERSISTENT);
} catch (ZkNoNodeException e) {
// process节点不存在，出现了rollback/shutdown操作，直接忽略
logger.warn("pipelineId[{}] transform ignore processId[{}] single by data:{}",
new Object[] { data.getPipelineId(), data.getProcessId(), data });
} catch (ZkNodeExistsException e) {
// process节点已存在，出现了ConnectionLoss retry操作
logger.warn("pipelineId[{}] transform ignore processId[{}] single by data:{}",
new Object[] { data.getPipelineId(), data.getProcessId(), data });
} catch (ZkException e) {
throw new ArbitrateException("transform_single", e.getMessage(), e);
}
}
}