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。
