io.druid.firehose.kafka.KafkaEightFirehoseFactory.java Source code

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Here is the source code for io.druid.firehose.kafka.KafkaEightFirehoseFactory.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group Inc.
 *
 * 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 io.druid.firehose.kafka;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Sets;
import com.metamx.common.logger.Logger;
import io.druid.data.input.ByteBufferInputRowParser;
import io.druid.data.input.Firehose;
import io.druid.data.input.FirehoseFactory;
import io.druid.data.input.InputRow;
import kafka.consumer.Consumer;
import kafka.consumer.ConsumerConfig;
import kafka.consumer.ConsumerIterator;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

/**
 */
public class KafkaEightFirehoseFactory implements FirehoseFactory<ByteBufferInputRowParser> {
    private static final Logger log = new Logger(KafkaEightFirehoseFactory.class);

    @JsonProperty
    private final Properties consumerProps;

    @JsonProperty
    private final String feed;

    @JsonCreator
    public KafkaEightFirehoseFactory(@JsonProperty("consumerProps") Properties consumerProps,
            @JsonProperty("feed") String feed

    ) {
        this.consumerProps = consumerProps;
        this.feed = feed;
    }

    @Override
    public Firehose connect(final ByteBufferInputRowParser firehoseParser) throws IOException {
        Set<String> newDimExclus = Sets.union(
                firehoseParser.getParseSpec().getDimensionsSpec().getDimensionExclusions(),
                Sets.newHashSet("feed"));
        final ByteBufferInputRowParser theParser = firehoseParser
                .withParseSpec(firehoseParser.getParseSpec().withDimensionsSpec(
                        firehoseParser.getParseSpec().getDimensionsSpec().withDimensionExclusions(newDimExclus)));

        final ConsumerConnector connector = Consumer.createJavaConsumerConnector(new ConsumerConfig(consumerProps));

        final Map<String, List<KafkaStream<byte[], byte[]>>> streams = connector
                .createMessageStreams(ImmutableMap.of(feed, 1));

        final List<KafkaStream<byte[], byte[]>> streamList = streams.get(feed);
        if (streamList == null || streamList.size() != 1) {
            return null;
        }

        final KafkaStream<byte[], byte[]> stream = streamList.get(0);
        final ConsumerIterator<byte[], byte[]> iter = stream.iterator();

        return new Firehose() {
            @Override
            public boolean hasMore() {
                return iter.hasNext();
            }

            @Override
            public InputRow nextRow() {
                final byte[] message = iter.next().message();

                if (message == null) {
                    return null;
                }

                return theParser.parse(ByteBuffer.wrap(message));
            }

            @Override
            public Runnable commit() {
                return new Runnable() {
                    @Override
                    public void run() {
                        /*
                          This is actually not going to do exactly what we want, cause it will be called asynchronously
                          after the persist is complete.  So, it's going to commit that it's processed more than was actually
                          persisted.  This is unfortunate, but good enough for now.  Should revisit along with an upgrade
                          of our Kafka version.
                        */

                        log.info("committing offsets");
                        connector.commitOffsets();
                    }
                };
            }

            @Override
            public void close() throws IOException {
                connector.shutdown();
            }
        };
    }

}