/*
* 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.streaming.examples.kafka;
import org.apache.flink.api.common.restartstrategy.RestartStrategies;
import org.apache.flink.api.java.utils.ParameterTool;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer08;
import org.apache.flink.streaming.util.serialization.SimpleStringSchema;
/**
* Read Strings from Kafka and print them to standard out.
* Note: On a cluster, DataStream.print() will print to the TaskManager's .out file!
*
* Please pass the following arguments to run the example:
* --topic test --bootstrap.servers localhost:9092 --zookeeper.connect localhost:2181 --group.id myconsumer
*
*/
public class ReadFromKafka {
public static void main(String[] args) throws Exception {
// parse input arguments
final ParameterTool parameterTool = ParameterTool.fromArgs(args);
if(parameterTool.getNumberOfParameters() < 4) {
System.out.println("Missing parameters!\nUsage: Kafka --topic <topic> " +
"--bootstrap.servers <kafka brokers> --zookeeper.connect <zk quorum> --group.id <some id>");
return;
}
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.getConfig().disableSysoutLogging();
env.getConfig().setRestartStrategy(RestartStrategies.fixedDelayRestart(4, 10000));
env.enableCheckpointing(5000); // create a checkpoint every 5 seconds
env.getConfig().setGlobalJobParameters(parameterTool); // make parameters available in the web interface
DataStream<String> messageStream = env
.addSource(new FlinkKafkaConsumer08<>(
parameterTool.getRequired("topic"),
new SimpleStringSchema(),
parameterTool.getProperties()));
// write kafka stream to standard out.
messageStream.print();
env.execute("Read from Kafka example");
}
}