/*
* Druid - a distributed column store.
* Copyright (C) 2012, 2013 Metamarkets Group Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package io.druid.server.bridge;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Charsets;
import com.google.inject.Inject;
import com.metamx.common.guava.Sequence;
import com.metamx.common.guava.Sequences;
import com.metamx.common.logger.Logger;
import com.metamx.http.client.HttpClient;
import com.metamx.http.client.response.StatusResponseHandler;
import com.metamx.http.client.response.StatusResponseHolder;
import io.druid.client.selector.Server;
import io.druid.curator.discovery.ServerDiscoverySelector;
import io.druid.guice.annotations.Global;
import io.druid.query.Query;
import io.druid.query.QueryRunner;
import io.druid.query.QuerySegmentWalker;
import io.druid.query.SegmentDescriptor;
import org.joda.time.Interval;
import java.net.URL;
import java.util.List;
import java.util.Map;
/**
*/
public class BridgeQuerySegmentWalker implements QuerySegmentWalker
{
private static final Logger log = new Logger(BridgeQuerySegmentWalker.class);
private final ServerDiscoverySelector brokerSelector;
private final HttpClient httpClient;
private final ObjectMapper jsonMapper;
private final StatusResponseHandler responseHandler;
@Inject
public BridgeQuerySegmentWalker(
ServerDiscoverySelector brokerSelector,
@Global HttpClient httpClient,
ObjectMapper jsonMapper
)
{
this.brokerSelector = brokerSelector;
this.httpClient = httpClient;
this.jsonMapper = jsonMapper;
this.responseHandler = new StatusResponseHandler(Charsets.UTF_8);
}
@Override
public <T> QueryRunner<T> getQueryRunnerForIntervals(
Query<T> query, Iterable<Interval> intervals
)
{
return makeRunner();
}
@Override
public <T> QueryRunner<T> getQueryRunnerForSegments(
Query<T> query, Iterable<SegmentDescriptor> specs
)
{
return makeRunner();
}
private <T> QueryRunner<T> makeRunner()
{
return new QueryRunner<T>()
{
@Override
public Sequence<T> run(Query<T> query, Map<String, Object> context)
{
try {
Server instance = brokerSelector.pick();
if (instance == null) {
return Sequences.empty();
}
final String url = String.format(
"http://%s/druid/v2/",
brokerSelector.pick().getHost()
);
StatusResponseHolder response = httpClient.post(new URL(url))
.setContent(
"application/json",
jsonMapper.writeValueAsBytes(query)
)
.go(responseHandler)
.get();
List<T> results = jsonMapper.readValue(
response.getContent(), new TypeReference<List<T>>()
{
}
);
return Sequences.simple(results);
}
catch (Exception e) {
log.error(e, "Exception with bridge query");
return Sequences.empty();
}
}
};
}
}