Flink初试——对接Kafka

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简介: Flink初试——对接Kafka

本篇文章我们用 Flink Kafka Connector对接Kafka,实现一个简单的报警业务。我们暂时不去谈论理论,先上手实现这个简单的需求。

flink-connector-kafka是 flink 内置的Kafka连接器,包含了从topic读取数据的Flink Kafka Consumer 和 向topic写入数据的flink kafka producer,除了基本功能外还提供了基于 checkpoint 机制提供了完美的容错能力。

本文基于flink 1.10.1 和 flink-connector-kafka-0.10_2.11版本,pom如下:

<dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka-0.10_2.11</artifactId>
            <version>1.10.0</versio>
</dependency>

以企业常见的预警业务为例,本文要实现的业务逻辑很简单,当设备上报的油桶余量不足10%时,便生成一个报警,这里我们将报警写入MySQL,以供web业务端展示报警报表。

首先我们用网络数据调试器向网关模拟发送数据,网关会将数据解析后写入kafka


kafka-console-consumer --bootstrap-server cdh1.macro.com:9092,cdh2.macro.com:9092,cdh3.macro.com:9092 --from-beginning --topic fill
{"addTime":1593147840000,"currentAmount":0.3,"devId":"XT365-000170","devStatus":"1","ifOffline":"1","ip":"127.0.0.1","leftTankAmount":5,"realTotalAmount":2377.39,"registerTime":1606658457000,"settingAmount":0.3,"tankCapacity":1000,"totalAmount":2017.9315}
{"addTime":1593147840000,"currentAmount":0.3,"devId":"XT365-000170","devStatus":"1","ifOffline":"1","ip":"127.0.0.1","leftTankAmount":5,"realTotalAmount":2377.69,"registerTime":1606658458000,"settingAmount":0.3,"tankCapacity":1000,"totalAmount":2017.9315}
^C20/11/29 23:26:55 INFO internals.ConsumerCoordinator: [Consumer clientId=consumer-console-consumer-82199-1, groupId=console-consumer-82199] Revoke previously assigned partitions fill-0
20/11/29 23:26:55 INFO internals.AbstractCoordinator: [Consumer clientId=consumer-console-consumer-82199-1, groupId=console-consumer-82199] Member consumer-console-consumer-82199-1-aa5fc2e6-1f06-4714-9d89-fe080a9400e2 sending LeaveGroup request to coordinator cdh2.macro.com:9092 (id: 2147483598 rack: null) due to the consumer is being closed
Processed a total of 1200 messages


可以看到我们已经向kafka生产了1200条数据了

接下来我们写一段代码来消费kafka数据,并将报警结果写入MySQL

import com.alibaba.fastjson.JSONObject;
import com.iiot.bean.InSufficient;
import com.iiot.commCommon.Fill;
import com.iiot.jdbc.MySQLSinks;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
import org.apache.flink.streaming.api.windowing.time.Time;
import java.util.List;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer010;
import org.apache.flink.util.Collector;
import org.apache.flink.shaded.guava18.com.google.common.collect.Lists;
import org.apache.flink.streaming.api.functions.windowing.AllWindowFunction;
import java.util.Properties;
public class InSufficientOilAlarms {
    public static void main(String[] args) throws Exception{
        //构建流执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        //kafka
        Properties prop = new Properties();
        prop.put("bootstrap.servers", "cdh1.macro.com:9092,cdh2.macro.com:9092,cdh3.macro.com:9092");
//        prop.put("zookeeper.connect", "localhost:2181");
        prop.put("group.id", "fill6");
        prop.put("key.serializer", "org.apache.kafka.common.serialization.StringDeserializer");
        prop.put("value.serializer", "org.apache.kafka.common.serialization.StringDeserializer");
        prop.put("auto.offset.reset", "earliest");
        DataStreamSource<String> stream = env
                .addSource(new FlinkKafkaConsumer010<String>(
                        "fill",
                        new SimpleStringSchema(), prop)).
                //单线程打印,控制台不乱序,不影响结果
                setParallelism(1);
        //从kafka里读取数据,转换成Person对象
        DataStream<Fill> dataStream = stream.map(value ->
                JSONObject.parseObject(value, Fill.class)
        );
        SingleOutputStreamOperator<InSufficient> result = dataStream.map(new MapFunction<Fill, InSufficient>() {
                           @Override
                           public InSufficient map(Fill fill) throws Exception {
                               InSufficient inSufficient = new InSufficient();
                               Float leftTankAmount = fill.getLeftTankAmount();
                               Float tankCapacity = fill.getTankCapacity();
                               String devCode = fill.getDevId();
                               long timeBegin = fill.getAddTime().getTime();
                               System.out.println("devCode:-------------------------------------------------" + devCode);
                               String alarmType = "";
                               if ((leftTankAmount / tankCapacity) < 0.1 ) {
                                   alarmType = "inSufficientOil";
                                   inSufficient.setDev_code(devCode);
                                   inSufficient.setCreateTime(System.currentTimeMillis());
                                   inSufficient.setTimeBegin(timeBegin);
                                   inSufficient.setAlarmType(alarmType);
                                   inSufficient.setRemainAmount(leftTankAmount);
                               }
                               return inSufficient;
                           }
                       }
        );
        //收集5秒钟的总数
        result.timeWindowAll(Time.seconds(5L)).
                apply(new AllWindowFunction<InSufficient, List<InSufficient>, TimeWindow>() {
                    @Override
                    public void apply(TimeWindow timeWindow, Iterable<InSufficient> iterable, Collector<List<InSufficient>> out) throws Exception {
                        List<InSufficient> inSufficients = Lists.newArrayList(iterable);
                        if(inSufficients.size() > 0) {
                            System.out.println("5秒的总共收到的条数:" + inSufficients.size());
                            out.collect(inSufficients);
                        }
                    }
                })
                //sink 到数据库
                .addSink(new MySQLSinks());
        //打印到控制台
        //.print();
        env.execute("kafka 消费任务开始");
    }
}


将项目打包,传到集群中,用Flink on YARN的方式运行作业

[root@cdh3 bin]# flink run -m yarn-cluster -c com.iiot.alarm.InSufficientOilAlarms /data0/flinkdemo/stream-1.0-SNAPSHOT-jar-with-dependencies.jar 
20/11/30 01:40:15 INFO cli.CliFrontend: --------------------------------------------------------------------------------
20/11/30 01:40:15 INFO cli.CliFrontend:  Starting Command Line Client (Version: 1.10.0-csa1.2.0.0, Rev:04dddd1, Date:29.05.2020 @ 14:54:45 UTC)
20/11/30 01:40:15 INFO cli.CliFrontend:  OS current user: root
20/11/30 01:40:16 INFO cli.CliFrontend:  Current Hadoop/Kerberos user: hdfs
20/11/30 01:40:16 INFO cli.CliFrontend:  JVM: Java HotSpot(TM) 64-Bit Server VM - Oracle Corporation - 1.8/25.171-b11
20/11/30 01:40:16 INFO cli.CliFrontend:  Maximum heap size: 3531 MiBytes
20/11/30 01:40:16 INFO cli.CliFrontend:  JAVA_HOME: /usr/java/latest
20/11/30 01:40:16 INFO cli.CliFrontend:  Hadoop version: 2.7.5
20/11/30 01:40:16 INFO cli.CliFrontend:  JVM Options:
20/11/30 01:40:16 INFO cli.CliFrontend:     -Datlas.conf=/etc/atlas/conf/
20/11/30 01:40:16 INFO cli.CliFrontend:     -Dlog.file=/var/log/flink/flink-root-client-cdh3.macro.com.log
20/11/30 01:40:16 INFO cli.CliFrontend:     -Dlog4j.configuration=file:/etc/flink/conf/log4j-cli.properties
20/11/30 01:40:16 INFO cli.CliFrontend:     -Dlogback.configurationFile=file:/etc/flink/conf/logback.xml
20/11/30 01:40:16 INFO cli.CliFrontend:  Program Arguments:
20/11/30 01:40:16 INFO cli.CliFrontend:     run
20/11/30 01:40:16 INFO cli.CliFrontend:     -m
20/11/30 01:40:16 INFO cli.CliFrontend:     yarn-cluster
20/11/30 01:40:16 INFO cli.CliFrontend:     -c
20/11/30 01:40:16 INFO cli.CliFrontend:     com.iiot.alarm.InSufficientOilAlarms
20/11/30 01:40:16 INFO cli.CliFrontend:     /data0/flinkdemo/stream-1.0-SNAPSHOT-jar-with-dependencies.jar
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:java.io.tmpdir=/tmp
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:java.compiler=<NA>
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:os.name=Linux
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:os.arch=amd64
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:os.version=3.10.0-327.el7.x86_64
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:user.name=root
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:user.home=/root
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:user.dir=/opt/cloudera/parcels/FLINK-1.10.0-csa1.2.0.0-cdh7.1.1.0-565-3454809/bin
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:os.memory.free=134MB
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:os.memory.max=3531MB
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Client environment:os.memory.total=359MB
20/11/30 01:40:51 INFO utils.Compatibility: Using emulated InjectSessionExpiration
20/11/30 01:40:51 INFO imps.CuratorFrameworkImpl: Starting
20/11/30 01:40:51 INFO zookeeper.ZooKeeper: Initiating client connection, connectString=cdh1.macro.com:2181,cdh2.macro.com:2181,cdh3.macro.com:2181 sessionTimeout=60000 watcher=org.apache.flink.shaded.curator.org.apache.curator.ConnectionState@1460c81d
20/11/30 01:40:51 INFO common.X509Util: Setting -D jdk.tls.rejectClientInitiatedRenegotiation=true to disable client-initiated TLS renegotiation
20/11/30 01:40:51 INFO zookeeper.ClientCnxnSocket: jute.maxbuffer value is 4194304 Bytes
20/11/30 01:40:51 INFO zookeeper.ClientCnxn: zookeeper.request.timeout value is 0. feature enabled=
20/11/30 01:40:51 WARN zookeeper.ClientCnxn: SASL configuration failed: javax.security.auth.login.LoginException: No JAAS configuration section named 'Client' was found in specified JAAS configuration file: '/tmp/jaas-8202592158525653501.conf'. Will continue connection to Zookeeper server without SASL authentication, if Zookeeper server allows it.
20/11/30 01:40:51 INFO zookeeper.ClientCnxn: Opening socket connection to server cdh1.macro.com/192.168.0.171:2181
20/11/30 01:40:51 INFO zookeeper.ClientCnxn: Socket connection established, initiating session, client: /192.168.0.208:38183, server: cdh1.macro.com/192.168.0.171:2181
20/11/30 01:40:51 ERROR curator.ConnectionState: Authentication failed
20/11/30 01:40:51 INFO imps.CuratorFrameworkImpl: Default schema
20/11/30 01:40:51 INFO zookeeper.ClientCnxn: Session establishment complete on server cdh1.macro.com/192.168.0.171:2181, sessionid = 0x3008be9995512b4, negotiated timeout = 60000
20/11/30 01:40:51 INFO state.ConnectionStateManager: State change: CONNECTED
20/11/30 01:40:51 INFO imps.EnsembleTracker: New config event received: {server.1=cdh2.macro.com:3181:4181:participant, version=0, server.3=cdh1.macro.com:3181:4181:participant, server.2=cdh3.macro.com:3181:4181:participant}
20/11/30 01:40:51 ERROR imps.EnsembleTracker: Invalid config event received: {server.1=cdh2.macro.com:3181:4181:participant, version=0, server.3=cdh1.macro.com:3181:4181:participant, server.2=cdh3.macro.com:3181:4181:participant}
20/11/30 01:40:51 INFO imps.EnsembleTracker: New config event received: {server.1=cdh2.macro.com:3181:4181:participant, version=0, server.3=cdh1.macro.com:3181:4181:participant, server.2=cdh3.macro.com:3181:4181:participant}
20/11/30 01:40:51 ERROR imps.EnsembleTracker: Invalid config event received: {server.1=cdh2.macro.com:3181:4181:participant, version=0, server.3=cdh1.macro.com:3181:4181:participant, server.2=cdh3.macro.com:3181:4181:participant}
20/11/30 01:40:52 INFO leaderretrieval.ZooKeeperLeaderRetrievalService: Starting ZooKeeperLeaderRetrievalService /leader/rest_server_lock.

可以在YARN作业中看到Flink的做作业一直在运行。

flink dashboard也可以看到作业一直在运行:

进入YARN reourcemanager里面查看作业运行日志:

可以看到MySQL已经插入数据了。


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