/**
* 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 backtype.storm.drpc;
import backtype.storm.Config;
import backtype.storm.ILocalDRPC;
import backtype.storm.generated.DRPCRequest;
import backtype.storm.generated.DistributedRPCInvocations;
import backtype.storm.spout.SpoutOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichSpout;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;
import backtype.storm.utils.ServiceRegistry;
import backtype.storm.utils.Utils;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.thrift7.TException;
import org.json.simple.JSONValue;
public class DRPCSpout extends BaseRichSpout {
public static Logger LOG = LoggerFactory.getLogger(DRPCSpout.class);
SpoutOutputCollector _collector;
List<DRPCInvocationsClient> _clients = new ArrayList<DRPCInvocationsClient>();
String _function;
String _local_drpc_id = null;
private static class DRPCMessageId {
String id;
int index;
public DRPCMessageId(String id, int index) {
this.id = id;
this.index = index;
}
}
public DRPCSpout(String function) {
_function = function;
}
public DRPCSpout(String function, ILocalDRPC drpc) {
_function = function;
_local_drpc_id = drpc.getServiceId();
}
@Override
public void open(Map conf, TopologyContext context, SpoutOutputCollector collector) {
_collector = collector;
if(_local_drpc_id==null) {
int numTasks = context.getComponentTasks(context.getThisComponentId()).size();
int index = context.getThisTaskIndex();
int port = Utils.getInt(conf.get(Config.DRPC_INVOCATIONS_PORT));
List<String> servers = (List<String>) conf.get(Config.DRPC_SERVERS);
if(servers == null || servers.isEmpty()) {
throw new RuntimeException("No DRPC servers configured for topology");
}
if(numTasks < servers.size()) {
for(String s: servers) {
_clients.add(new DRPCInvocationsClient(s, port));
}
} else {
int i = index % servers.size();
_clients.add(new DRPCInvocationsClient(servers.get(i), port));
}
}
}
@Override
public void close() {
for(DRPCInvocationsClient client: _clients) {
client.close();
}
}
@Override
public void nextTuple() {
boolean gotRequest = false;
if(_local_drpc_id==null) {
for(int i=0; i<_clients.size(); i++) {
DRPCInvocationsClient client = _clients.get(i);
try {
DRPCRequest req = client.fetchRequest(_function);
if(req.get_request_id().length() > 0) {
Map returnInfo = new HashMap();
returnInfo.put("id", req.get_request_id());
returnInfo.put("host", client.getHost());
returnInfo.put("port", client.getPort());
gotRequest = true;
_collector.emit(new Values(req.get_func_args(), JSONValue.toJSONString(returnInfo)), new DRPCMessageId(req.get_request_id(), i));
break;
}
} catch (TException e) {
LOG.error("Failed to fetch DRPC result from DRPC server", e);
}
}
} else {
DistributedRPCInvocations.Iface drpc = (DistributedRPCInvocations.Iface) ServiceRegistry.getService(_local_drpc_id);
if(drpc!=null) { // can happen during shutdown of drpc while topology is still up
try {
DRPCRequest req = drpc.fetchRequest(_function);
if(req.get_request_id().length() > 0) {
Map returnInfo = new HashMap();
returnInfo.put("id", req.get_request_id());
returnInfo.put("host", _local_drpc_id);
returnInfo.put("port", 0);
gotRequest = true;
_collector.emit(new Values(req.get_func_args(), JSONValue.toJSONString(returnInfo)), new DRPCMessageId(req.get_request_id(), 0));
}
} catch (TException e) {
throw new RuntimeException(e);
}
}
}
if(!gotRequest) {
Utils.sleep(1);
}
}
@Override
public void ack(Object msgId) {
}
@Override
public void fail(Object msgId) {
DRPCMessageId did = (DRPCMessageId) msgId;
DistributedRPCInvocations.Iface client;
if(_local_drpc_id == null) {
client = _clients.get(did.index);
} else {
client = (DistributedRPCInvocations.Iface) ServiceRegistry.getService(_local_drpc_id);
}
try {
client.failRequest(did.id);
} catch (TException e) {
LOG.error("Failed to fail request", e);
}
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("args", "return-info"));
}
}