| /** |
| * 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 |
| * <p> |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * <p> |
| * 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.apache.crunch.kafka; |
| |
| import com.google.common.collect.ImmutableList; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.kafka.clients.consumer.Consumer; |
| import org.apache.kafka.clients.consumer.KafkaConsumer; |
| import org.apache.kafka.common.PartitionInfo; |
| import org.apache.kafka.common.TopicPartition; |
| |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Properties; |
| import java.util.stream.Collectors; |
| |
| /** |
| * Simple utilities for retrieving offset and Kafka information to assist in setting up and configuring a |
| * {@link org.apache.crunch.kafka.record.KafkaSource} instance. |
| */ |
| public class KafkaUtils { |
| |
| /** |
| * Configuration property for the number of retry attempts that will be made to Kafka. |
| */ |
| public static final String KAFKA_RETRY_ATTEMPTS_KEY = "org.apache.crunch.kafka.retry.attempts"; |
| |
| /** |
| * Default number of retry attempts. |
| */ |
| public static final int KAFKA_RETRY_ATTEMPTS_DEFAULT = 120; |
| public static final String KAFKA_RETRY_ATTEMPTS_DEFAULT_STRING = Integer.toString(KAFKA_RETRY_ATTEMPTS_DEFAULT); |
| |
| /** |
| * Converts the provided {@code config} into a {@link Properties} object to connect with Kafka. |
| * |
| * @param config the config to read properties |
| * @return a properties instance populated with all of the values inside the provided {@code config}. |
| */ |
| public static Properties getKafkaConnectionProperties(Configuration config) { |
| Properties props = new Properties(); |
| for (Map.Entry<String, String> value : config) { |
| props.setProperty(value.getKey(), value.getValue()); |
| } |
| |
| return props; |
| } |
| |
| /** |
| * Adds the {@code properties} to the provided {@code config} instance. |
| * |
| * @param properties the properties to add to the config. |
| * @param config the configuration instance to be modified. |
| * @return the config instance with the populated properties |
| */ |
| public static Configuration addKafkaConnectionProperties(Properties properties, Configuration config) { |
| for (String name : properties.stringPropertyNames()) { |
| config.set(name, properties.getProperty(name)); |
| } |
| return config; |
| } |
| |
| /** |
| * Returns the {@link TopicPartition}s in a topic, returns an empty list if the topic does not exist. |
| */ |
| public static List<TopicPartition> getTopicPartitions(Consumer<?, ?> kafkaConsumer, String topic) { |
| List<PartitionInfo> partitionInfos = kafkaConsumer.partitionsFor(topic); |
| |
| // This conversion of null to empty list is consistent with https://issues.apache.org/jira/browse/KAFKA-2358 |
| if (partitionInfos == null) { |
| return ImmutableList.of(); |
| } else { |
| return partitionInfos.stream() |
| .map(partitionInfo -> new TopicPartition(partitionInfo.topic(), partitionInfo.partition())) |
| .collect(Collectors.toList()); |
| } |
| } |
| |
| } |