| /* |
| * 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 samza.examples.cookbook; |
| |
| import org.apache.samza.application.StreamApplication; |
| import org.apache.samza.config.Config; |
| import org.apache.samza.operators.MessageStream; |
| import org.apache.samza.operators.OutputStream; |
| import org.apache.samza.operators.StreamGraph; |
| import org.apache.samza.operators.windows.WindowPane; |
| import org.apache.samza.operators.windows.Windows; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.time.Duration; |
| import java.util.Collection; |
| import java.util.function.Function; |
| |
| /** |
| * In this example, we group page views by userId into sessions, and compute the number of page views for each user |
| * session. A session is considered closed when there is no user activity for a 3 second duration. |
| * |
| * <p>Concepts covered: Using session windows to group data in a stream, Re-partitioning a stream. |
| * |
| * To run the below example: |
| * |
| * <ol> |
| * <li> |
| * Ensure that the topic "pageview-session-input" is created <br/> |
| * ./kafka-topics.sh --zookeeper localhost:2181 --create --topic pageview-session-input --partitions 2 --replication-factor 1 |
| * </li> |
| * <li> |
| * Run the application using the ./bin/run-app.sh script <br/> |
| * ./deploy/samza/bin/run-app.sh --config-factory=org.apache.samza.config.factories.PropertiesConfigFactory <br/> |
| * --config-path=file://$PWD/deploy/samza/config/pageview-sessionizer.properties) |
| * </li> |
| * <li> |
| * Produce some messages to the "pageview-session-input" topic <br/> |
| * user1,india,google.com <br/> |
| * user2,china,yahoo.com |
| * </li> |
| * <li> |
| * Consume messages from the "pageview-session-output" topic (e.g. bin/kafka-console-consumer.sh) |
| * ./bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic pageview-sessions-output <br/> |
| * --property print.key=true |
| * </li> |
| * </ol> |
| * |
| */ |
| public class PageViewSessionizerApp implements StreamApplication { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(PageViewSessionizerApp.class); |
| private static final String INPUT_TOPIC = "pageview-session-input"; |
| private static final String OUTPUT_TOPIC = "pageview-session-output"; |
| |
| @Override |
| public void init(StreamGraph graph, Config config) { |
| |
| MessageStream<String> pageViews = graph.<String, String, String>getInputStream(INPUT_TOPIC, (k, v) -> v); |
| |
| OutputStream<String, String, WindowPane<String, Collection<String>>> outputStream = graph |
| .getOutputStream(OUTPUT_TOPIC, m -> m.getKey().getKey(), m -> new Integer(m.getMessage().size()).toString()); |
| |
| Function<String, String> keyFn = pageView -> new PageView(pageView).getUserId(); |
| |
| pageViews |
| .partitionBy(keyFn) |
| .window(Windows.keyedSessionWindow(keyFn, Duration.ofSeconds(3))) |
| .sendTo(outputStream); |
| } |
| } |