test/kafka/src/main/java/org/apache/rya/test/kafka/KafkaTestInstanceRule.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.apache.rya.test.kafka;

import java.util.Properties;
import java.util.Set;
import java.util.UUID;

import org.I0Itec.zkclient.ZkClient;
import org.apache.kafka.clients.CommonClientConfigs;
import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.junit.rules.ExternalResource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import kafka.admin.AdminUtils;
import kafka.admin.RackAwareMode;
import kafka.utils.ZKStringSerializer$;
import kafka.utils.ZkUtils;


/**
 * Provides a JUnit Rule for interacting with the {@link EmbeddedKafkaSingleton}.
 *
 */
public class KafkaTestInstanceRule extends ExternalResource {
    private static final Logger logger = LoggerFactory.getLogger(KafkaTestInstanceRule.class);
    private static final EmbeddedKafkaInstance kafkaInstance = EmbeddedKafkaSingleton.getInstance();
    private String kafkaTopicName;
    private final boolean createTopic;

    /**
     * @param createTopic - If true, a topic shall be created for the value
     *            provided by {@link #getKafkaTopicName()}. If false, no topics
     *            shall be created.
     */
    public KafkaTestInstanceRule(final boolean createTopic) {
        this.createTopic = createTopic;
    }

    /**
     * @return A unique topic name for this test execution. If multiple topics are required by a test, use this value as
     *         a prefix.
     */
    public String getKafkaTopicName() {
        if (kafkaTopicName == null) {
            throw new IllegalStateException("Cannot get Kafka Topic Name outside of a test execution.");
        }
        return kafkaTopicName;
    }

    @Override
    protected void before() throws Throwable {
        // Get the next kafka topic name.
        kafkaTopicName = kafkaInstance.getUniqueTopicName();

        if(createTopic) {
            createTopic(kafkaTopicName);
        }
    }

    @Override
    protected void after() {
        kafkaTopicName = null;
    }

    /**
     * Utility method to provide additional unique topics if they are required.
     * @param topicName - The Kafka topic to create.
     */
    public void createTopic(final String topicName) {
        // Setup Kafka.
        ZkUtils zkUtils = null;
        try {
            logger.info("Creating Kafka Topic: '{}'", topicName);
            zkUtils = ZkUtils.apply(new ZkClient(kafkaInstance.getZookeeperConnect(), 30000, 30000, ZKStringSerializer$.MODULE$), false);
            AdminUtils.createTopic(zkUtils, topicName, 1, 1, new Properties(), RackAwareMode.Disabled$.MODULE$);
        }
        finally {
            if(zkUtils != null) {
                zkUtils.close();
            }
        }
    }

    /**
     * Marks a topic for deletion. You may have to wait some time for the delete to actually complete.
     *
     * @param topicName - The topic that will be deleted. (not null)
     */
    public void deleteTopic(final String topicName) {
        ZkUtils zkUtils = null;
        try {
            logger.info("Deleting Kafka Topic: '{}'", topicName);
            zkUtils = ZkUtils.apply(new ZkClient(kafkaInstance.getZookeeperConnect(), 30000, 30000, ZKStringSerializer$.MODULE$), false);
            AdminUtils.deleteTopic(zkUtils, topicName);
        }
        finally {
            if(zkUtils != null) {
                zkUtils.close();
            }
        }
    }

    /**
     * Delete all of the topics that are in the embedded Kafka instance.
     *
     * @throws InterruptedException Interrupted while waiting for the topics to be deleted.
     */
    public void deleteAllTopics() throws InterruptedException {
        // Setup the consumer that is used to list topics for the source.
        final Properties consumerProperties = createBootstrapServerConfig();
        consumerProperties.setProperty(ConsumerConfig.GROUP_ID_CONFIG, UUID.randomUUID().toString());
        consumerProperties.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        consumerProperties.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());

        try(final Consumer<String, String> listTopicsConsumer = new KafkaConsumer<>(consumerProperties)) {
            // Mark all existing topics for deletion.
            Set<String> topics = listTopicsConsumer.listTopics().keySet();
            for(final String topic : topics) {
                deleteTopic(topic);
            }

            // Loop and wait until they are all gone.
            while(!topics.isEmpty()) {
                Thread.sleep(100);
                topics = listTopicsConsumer.listTopics().keySet();
            }
        }
    }

    /**
     * @return A new Property object containing the correct value for Kafka's
     *         {@link CommonClientConfigs#BOOTSTRAP_SERVERS_CONFIG}.
     */
    public Properties createBootstrapServerConfig() {
        return kafkaInstance.createBootstrapServerConfig();
    }

    /**
     * @return The hostnames of the Zookeeper servers.
     */
    public String getZookeeperServers() {
        return kafkaInstance.getZookeeperConnect();
    }

    /**
     * @return The hostname of the Kafka Broker.
     */
    public String getKafkaHostname() {
        return kafkaInstance.getBrokerHost();
    }

    /**
     * @return The port of the Kafka Broker.
     */
    public String getKafkaPort() {
        return kafkaInstance.getBrokerPort();
    }
}