Kafka1TimestampedRecordExtractor.java
/*
* 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 org.wikimedia.gobblin.kafka;
import java.io.IOException;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;
import org.apache.kafka.common.record.TimestampType;
import org.apache.gobblin.configuration.WorkUnitState;
import org.apache.gobblin.kafka.client.ByteArrayBasedKafkaRecord;
import org.apache.gobblin.kafka.client.KafkaConsumerRecord;
import org.apache.gobblin.source.extractor.DataRecordException;
import org.apache.gobblin.source.extractor.extract.kafka.KafkaExtractor;
import org.wikimedia.gobblin.copy.Kafka1ConsumerClient;
import org.wikimedia.gobblin.TimestampedRecord;
import com.google.common.collect.ImmutableSet;
import lombok.extern.slf4j.Slf4j;
/**
* Extracts {@link TimestampedRecord} records from Kafka using Kafka1 client.
* The extracted record timestamp is set to the kafka record timestamp if the kafka
* record timestamp-type is in the list of extracted-timestamp-types defined using
* the property source.kafka.extract.timestampTypes (accepted values are CreateTime
* and LogAppendTime, or unset-property). If the timestamp is not extracted from the
* kafka record, it is set to current-timestamp if the state property
* source.kafka.extract.timestamp.defaultCurrent is set to true, and is absent otherwise.
* @param <P> The type of the deserialized payload from the kafka record.
*/
@Slf4j
public class Kafka1TimestampedRecordExtractor<P> extends KafkaExtractor<Object, Object> {
public static final String EXTRACTED_TIMESTAMP_TYPES_KEY = "source.kafka.extract.timestampTypes";
public static final String CURRENT_TIMESTAMP_AS_DEFAULT_KEY = "source.kafka.extract.timestamp.defaultCurrent";
private final ImmutableSet<TimestampType> extractedTimestampTypes;
private final boolean useCurrentTimestampAsDefault;
public Kafka1TimestampedRecordExtractor(WorkUnitState state) {
super(state);
this.extractedTimestampTypes = getExtractedTimestampTypes(state);
this.useCurrentTimestampAsDefault = getUseCurrentTimestampAsDefault(state);
}
/**
* Uses state EXTRACTED_TIMESTAMP_TYPES_KEY property to construct a list
* of {@link TimestampType} defining the types of kafka-timestamps that
* will lead to extracted records having kafka timestamp set.
* Accepted values are CreateTime and LogAppendTime, or unset-property (leading
* to all records having the default timestamp).
*
* @return The {@link TimestampType} list, empty if the property is not present.
* @Throws NoSuchElementException in case of invalid {@link TimestampType}
* @throws IllegalArgumentException if {@link TimestampType} is not of accepted values
*/
private ImmutableSet<TimestampType> getExtractedTimestampTypes(WorkUnitState state) {
ImmutableSet.Builder<TimestampType> result = ImmutableSet.builder();
if (state.contains(EXTRACTED_TIMESTAMP_TYPES_KEY)) {
for (String timestampTypeName : state.getPropAsList(EXTRACTED_TIMESTAMP_TYPES_KEY)) {
TimestampType timestampType = TimestampType.forName(timestampTypeName);
if (timestampType == TimestampType.CREATE_TIME || timestampType == TimestampType.LOG_APPEND_TIME) {
result.add(timestampType);
} else {
throw new IllegalArgumentException("Invalid TimestampType to extract: " + timestampType +
". Accepted values are CreateTime and/or LogAppendTime");
}
}
}
return result.build();
}
/**
* Uses state CURRENT_TIMESTAMP_AS_DEFAULT_KEY property to define if record timestamp
* should be set to current-time if kafka timestamp can't be used (by opposition to be absent).
*
* @return The {@link TimestampType} list, empty if the property is not present.
*/
private boolean getUseCurrentTimestampAsDefault(WorkUnitState state) throws NoSuchElementException {
return (state.contains(CURRENT_TIMESTAMP_AS_DEFAULT_KEY) &&
state.getPropAsBoolean(CURRENT_TIMESTAMP_AS_DEFAULT_KEY));
}
/**
* We need to override this protected method as the kafka timestamp information is not
* available in the {@link KafkaExtractor#decodeRecord(ByteArrayBasedKafkaRecord)} abstract method.
*/
@Override
protected TimestampedRecord<P> decodeKafkaMessage(KafkaConsumerRecord message) throws DataRecordException, IOException {
if (message instanceof Kafka1ConsumerClient.Kafka1ConsumerRecord) {
Kafka1ConsumerClient.Kafka1ConsumerRecord typedRecord = (Kafka1ConsumerClient.Kafka1ConsumerRecord)message;
// if value is null then this is a bad record that is returned for further error handling, so raise an error
if (typedRecord.getValue() == null) {
throw new DataRecordException("Could not decode Kafka record");
}
Optional<Long> timestamp = Optional.empty();
if (extractedTimestampTypes.contains(typedRecord.getTimestampType())) {
timestamp = Optional.of(typedRecord.getTimestamp());
} else if (useCurrentTimestampAsDefault) {
timestamp = Optional.of(System.currentTimeMillis());
}
return new TimestampedRecord(typedRecord.getValue(), timestamp);
} else {
throw new IllegalStateException(
"Unsupported KafkaConsumerRecord type. The record should be Kafka1ConsumerRecord but is " +
message.getClass().getCanonicalName());
}
}
/**
* Unreachable, as {@link KafkaExtractor#decodeKafkaMessage(KafkaConsumerRecord)} is override not to use this method.
*/
@Override
protected Object decodeRecord(ByteArrayBasedKafkaRecord kafkaConsumerRecord) throws IOException {
throw new IllegalArgumentException("Could not decode Kafka record");
}
// TODO: Implement schema getter option (for events!)
@Override
public Object getSchema() {
return null;
}
}