/*
* Copyright © 2014 Cask Data, 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 co.cask.cdap.metrics.process;
import co.cask.cdap.api.common.Bytes;
import co.cask.cdap.data2.OperationException;
import co.cask.cdap.data2.StatusCode;
import co.cask.cdap.data2.dataset2.lib.table.MetricsTable;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.collect.Maps;
import org.apache.twill.kafka.client.TopicPartition;
import java.util.Map;
import java.util.NavigableMap;
/**
* An abstraction on persistent storage of kafka consumer information.
*/
public final class KafkaConsumerMetaTable {
private static final byte[] OFFSET_COLUMN = Bytes.toBytes("o");
private final MetricsTable metaTable;
public KafkaConsumerMetaTable(MetricsTable metaTable) {
this.metaTable = metaTable;
}
public synchronized void save(Map<TopicPartition, Long> offsets) throws OperationException {
NavigableMap<byte[], NavigableMap<byte[], byte[]>> updates = Maps.newTreeMap(Bytes.BYTES_COMPARATOR);
for (Map.Entry<TopicPartition, Long> entry : offsets.entrySet()) {
updates.put(getKey(entry.getKey()), Bytes.immutableSortedMapOf(OFFSET_COLUMN, Bytes.toBytes(entry.getValue())));
}
try {
metaTable.put(updates);
} catch (Exception e) {
throw new OperationException(StatusCode.INTERNAL_ERROR, e.getMessage(), e);
}
}
/**
* Gets the offset of a given topic partition.
* @param topicPartition The topic and partition to fetch offset.
* @return The offset or {@code -1} if the offset is not found.
* @throws OperationException If there is an error when fetching.
*/
public synchronized long get(TopicPartition topicPartition) throws OperationException {
try {
byte[] result = metaTable.get(getKey(topicPartition), OFFSET_COLUMN);
if (result == null) {
return -1;
}
return Bytes.toLong(result);
} catch (Exception e) {
throw new OperationException(StatusCode.INTERNAL_ERROR, e.getMessage(), e);
}
}
private byte[] getKey(TopicPartition topicPartition) {
return Bytes.toBytes(String.format("%s.%02d", topicPartition.getTopic(), topicPartition.getPartition()));
}
}