接上文:一文说清flink从编码到部署上线
环境说明:MySQL:5.7;flink:1.14.0;hadoop:3.0.0;操作系统:CentOS 7.6;JDK:1.8.0_401。
1.代码实现
1.1 EnvUtil实现
EnvUtil用于创建flink的运行环境。
package com.zl.utils;
import org.apache.flink.api.common.restartstrategy.RestartStrategies;
import org.apache.flink.api.common.time.Time;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.contrib.streaming.state.EmbeddedRocksDBStateBackend;
import org.apache.flink.streaming.api.CheckpointingMode;
import org.apache.flink.streaming.api.environment.CheckpointConfig;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import java.time.Duration;
import java.time.ZoneOffset;
import java.util.concurrent.TimeUnit;
/**
* EnvUtil
* @description:
*/
public class EnvUtil {
/**
* 设置flink执行环境
* @param parallelism 并行度
*/
public static StreamExecutionEnvironment setFlinkEnv(int parallelism) {
// System.setProperty("HADOOP_USER_NAME", "用户名") 对应的是 hdfs文件系统目录下的路径:/user/用户名的文件夹名,本文为root
System.setProperty("HADOOP_USER_NAME", "root");
Configuration conf = new Configuration();
conf.setInteger("rest.port", 1000);
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment(conf);
if (parallelism >0 ){
//设置并行度
env.setParallelism(parallelism);
} else {
env.setParallelism(1);// 默认1
}
// 添加重启机制
env.setRestartStrategy(RestartStrategies.fixedDelayRestart(50, Time.minutes(6)));
// 启动checkpoint,设置模式为精确一次 (这是默认值),10*60*1000=60000
env.enableCheckpointing(600000, CheckpointingMode.EXACTLY_ONCE);
//rocksdb状态后端,启用增量checkpoint
env.setStateBackend(new EmbeddedRocksDBStateBackend(true));
//设置checkpoint路径
CheckpointConfig checkpointConfig = env.getCheckpointConfig();
// 同一时间只允许一个 checkpoint 进行(默认)
checkpointConfig.setMaxConcurrentCheckpoints(1);
//最小间隔,10*60*1000=60000
checkpointConfig.setMinPauseBetweenCheckpoints(60000);
// 取消任务后,checkpoint仍然保存
checkpointConfig.enableExternalizedCheckpoints(CheckpointConfig.ExternalizedCheckpointCleanup.RETAIN_ON_CANCELLATION);
//checkpoint容忍失败的次数
checkpointConfig.setTolerableCheckpointFailureNumber(5);
//checkpoint超时时间 默认10分钟
checkpointConfig.setCheckpointTimeout(TimeUnit.MINUTES.toMillis(10));
//禁用operator chain(方便排查反压)
env.disableOperatorChaining();
return env;
}
public static StreamTableEnvironment getFlinkTenv(StreamExecutionEnvironment env) {
StreamTableEnvironment tenv = StreamTableEnvironment.create(env);
//设置时区 东八
tenv.getConfig().setLocalTimeZone(ZoneOffset.ofHours(8));
Configuration configuration = tenv.getConfig().getConfiguration();
// 开启miniBatch
configuration.setString("table.exec.mini-batch.enabled", "true");
// 批量输出的间隔时间
configuration.setString("table.exec.mini-batch.allow-latency", "5 s");
// 防止OOM设置每个批次最多缓存数据的条数,可以设为2万条
configuration.setString("table.exec.mini-batch.size", "20000");
// 开启LocalGlobal
configuration.setString("table.optimizer.agg-phase-strategy", "TWO_PHASE");
//设置TTL API指定
tenv.getConfig().setIdleStateRetention(Duration.ofHours(25));
return tenv;
}
}
1.2 核心代码
package com.zl;
import com.zl.utils.EnvUtil;
import org.apache.flink.api.common.restartstrategy.RestartStrategies;
import org.apache.flink.api.common.time.Time;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.RestOptions;
import org.apache.flink.contrib.streaming.state.EmbeddedRocksDBStateBackend;
import org.apache.flink.streaming.api.CheckpointingMode;
import org.apache.flink.streaming.api.environment.CheckpointConfig;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.EnvironmentSettings;
import org.apache.flink.table.api.TableEnvironment;
import org.apache.flink.table.api.TableResult;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import java.util.concurrent.TimeUnit;
public class MysqlExampleSQL {
public static void main(String[] args) throws Exception {
// 配置运行环境,并行度1
StreamExecutionEnvironment env = EnvUtil.setFlinkEnv(1);
// 程序间隔离,每个程序单独设置
env.getCheckpointConfig().setCheckpointStorage("hdfs://10.86.97.191:9000/flinktest/MysqlExampleSQL");
EnvironmentSettings settings = EnvironmentSettings.newInstance().build();
StreamTableEnvironment tenv = StreamTableEnvironment.create(env, settings);
/**
* 数据库版本:8.0.27
* mysql sink
*/
tenv.executeSql(
" CREATE TABLE `sink_products` (" +
"id INT," +
"name STRING," +
"description STRING," +
"PRIMARY KEY (`id`) NOT ENFORCED" +
")with (" +
"'connector' = 'jdbc'," +
"'url' = 'jdbc:mysql://10.86.45.12:30105/flinktest2'," +
"'driver' = 'com.mysql.cj.jdbc.Driver'," +//com.mysql.jdbc.Driver,com.mysql.cj.jdbc.Driver
"'username' = '" + "root" + "'," +
"'password' = '" + "pwd" + "'," +// 记得修改为实际密码
"'table-name' = 'products'" +
")"
);
/**
* 数据库版本:5.7.20
* cdc方式同步业务库数据
*/
tenv.executeSql("CREATE TABLE `src_products`( " +
"id INT," +
"name STRING," +
"description STRING," +
"PRIMARY KEY (`id`) NOT ENFORCED" +
") with (" +
"'connector' = 'mysql-cdc', " +
"'hostname' = '" + "10.86.37.169" + "', " +
"'port' = '" + "3306" + "', " +
"'username' = '" + "root" + "', " +
"'password' = '" + "pwd" + "', " +// 记得修改为实际密码
"'database-name' = '" + "flinktest1" + "', " +
"'table-name' = 'products'," +
"'debezium.snapshot.mode' = 'initial'" +
")"
);
/**
* 数据同步
*/
TableResult tableResult1 = tenv.executeSql("INSERT INTO sink_products " +
"SELECT " +
"id, " +
"name, " +
"description " +
"FROM src_products");
// 通过 TableResult 来获取作业状态
tableResult1.print();
}
}
1.3 pom.xml
注意修改此处:
2.web UI
3.数据库
flinktest1.products
flinktest2.products
4.部署
相关构建、部署,参考:一文说清flink从编码到部署上线
部署脚本:
flink run-application -t yarn-application -Dparallelism.default=1 -Denv.java.opts=" -Dfile.encoding=UTF-8 -Dsun.jnu.encoding=UTF-8" -Dtaskmanager.memory.process.size=1g -Dyarn.application.name="FlinkCdcMysql" -Dtaskmanager.numberOfTaskSlots=1 -c com.zl.MysqlExampleSQL /home/FlickCDC-1.0-SNAPSHOT-jar-with-dependencies.jar
部署日志:
yarn:
5.常见问题
5.1 错误1
开发环境,错误日志:
“Caused by: java.lang.NoSuchMethodError: com.mysql.cj.CharsetMapping.getJavaEncodingForMysqlCharset(Ljava/lang/String;)Ljava/lang/String;”
解决:去掉pom.xml中“mysql-connector-java”相关依赖。
5.2 错误2
部署后,错误日志:
①“Caused by: org.apache.flink.table.api.ValidationException: Cannot discover a connector using option: ‘connector’=‘mysql-cdc’”。
②“Caused by: org.apache.flink.table.api.ValidationException: Could not find any factory for identifier ‘jdbc’ that implements ‘org.apache.flink.table.factories.DynamicTableFactory’ in the classpath”。
解决:
“flink-connector-jdbc_2.11-1.14.0.jar”、“flink-connector-mysql-cdc-2.4.0.jar”放到服务器flink的lib目录,如下图所示:
5.3 错误3
部署后,错误日志:
“ Exception java.lang.NoClassDefFoundError: com/mysql/cj/jdbc/Driver”。
解决:
“mysql-connector-java-8.0.27.jar”放到服务器flink的lib目录,如下图所示:
6.代码
完整代码见:https://gitee.com/core815/flink-cdc-mysql