docker/ops-playground-image/java/flink-playground-clickcountjob/src/main/java/org/apache/flink/playgrounds/ops/clickcount/ClickEventGenerator.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.flink.playgrounds.ops.clickcount;

import org.apache.flink.api.common.serialization.SerializationSchema;
import org.apache.flink.api.java.utils.ParameterTool;

import org.apache.flink.playgrounds.ops.clickcount.records.ClickEvent;
import org.apache.flink.playgrounds.ops.clickcount.records.ClickEventSerializationSchema;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.ByteArraySerializer;

import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import static org.apache.flink.playgrounds.ops.clickcount.ClickEventCount.WINDOW_SIZE;

/**
 * A generator which pushes {@link ClickEvent}s into a Kafka Topic configured via `--topic` and
 * `--bootstrap.servers`.
 *
 * <p> The generator creates the same number of {@link ClickEvent}s for all pages. The delay between
 * events is chosen such that processing time and event time roughly align. The generator always
 * creates the same sequence of events. </p>
 *
 */
public class ClickEventGenerator {

	public static final int EVENTS_PER_WINDOW = 1000;

	private static final List<String> pages = Arrays.asList("/help", "/index", "/shop", "/jobs", "/about", "/news");

	//this calculation is only accurate as long as pages.size() * EVENTS_PER_WINDOW divides the
	//window size
	public static final long DELAY = WINDOW_SIZE.toMilliseconds() / pages.size() / EVENTS_PER_WINDOW;

	public static void main(String[] args) throws Exception {

		final ParameterTool params = ParameterTool.fromArgs(args);

		String topic = params.get("topic", "input");

		Properties kafkaProps = createKafkaProperties(params);

		KafkaProducer<byte[], byte[]> producer = new KafkaProducer<>(kafkaProps);

		ClickIterator clickIterator = new ClickIterator();
		SerializationSchema<ClickEvent> clickSerializer = new ClickEventSerializationSchema();

		while (true) {

			byte[] message = clickSerializer.serialize(clickIterator.next());
			ProducerRecord<byte[], byte[]> record = new ProducerRecord<>(topic, message);
			producer.send(record);

			Thread.sleep(DELAY);
		}
	}

	private static Properties createKafkaProperties(final ParameterTool params) {
		String brokers = params.get("bootstrap.servers", "localhost:9092");
		Properties kafkaProps = new Properties();
		kafkaProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, brokers);
		kafkaProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, ByteArraySerializer.class.getCanonicalName());
		kafkaProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, ByteArraySerializer.class.getCanonicalName());
		return kafkaProps;
	}

	static class ClickIterator  {

		private Map<String, Long> nextTimestampPerKey;
		private int nextPageIndex;

		ClickIterator() {
			nextTimestampPerKey = new HashMap<>();
			nextPageIndex = 0;
		}

		ClickEvent next() {
			String page = nextPage();
			return new ClickEvent(nextTimestamp(page), page);
		}

		private Date nextTimestamp(String page) {
			long nextTimestamp = nextTimestampPerKey.getOrDefault(page, 0L);
			nextTimestampPerKey.put(page, nextTimestamp + WINDOW_SIZE.toMilliseconds() / EVENTS_PER_WINDOW);
			return new Date(nextTimestamp);
		}

		private String nextPage() {
			String nextPage = pages.get(nextPageIndex);
			if (nextPageIndex == pages.size() - 1) {
				nextPageIndex = 0;
			} else {
				nextPageIndex++;
			}
			return nextPage;
		}
	}
}