Flink SQL kafka连接器

版本说明

Flink和kafka的版本号有一定的匹配关系，操作成功的版本：

• Flink1.17.1
• kafka_2.12-3.3.1

添加kafka连接器依赖

将flink-sql-connector-kafka-1.17.1.jar上传到flink的lib目录下

下载flink-sql-connector-kafka连接器jar包

https://mvnrepository.com/artifact/org.apache.flink/flink-connector-kafka/1.17.1

上传到flink的lib目录下

[hadoop@node2 ~]$ cp flink-connector-kafka-1.17.1.jar $FLINK_HOME/lib

分发flink-connector-kafka-1.17.1.jar

xsync $FLINK_HOME/lib/flink-connector-kafka-1.17.1.jar

启动yarn-session

[hadoop@node2 ~]$ myhadoop.sh start
[hadoop@node2 ~]$ yarn-session.sh -d

启动kafka集群

[hadoop@node2 ~]$ zk.sh start
[hadoop@node2 ~]$ kf.sh start

创建kafka主题

查看主题
[hadoop@node2 ~]$ kafka-topics.sh --bootstrap-server node2:9092,node3:9092,node4:9092 --list
​
如果没有ws1,则创建
[hadoop@node2 ~]$ kafka-topics.sh --bootstrap-server node2:9092,node3:9092,node4:9092 --create --replication-factor 1 --partitions 1 --topic ws1
​

普通Kafka表

'connector' = 'kafka'

进入Flink SQL客户端

[hadoop@node2 ~]$ sql-client.sh embedded -s yarn-session
...
省略若干日志输出
...
Flink SQL> 

创建Kafka的映射表

CREATE TABLE t1( `event_time` TIMESTAMP(3) METADATA FROM 'timestamp',--列名和元数据名一致可以省略 FROM 'xxxx', VIRTUAL表示只读`partition` BIGINT METADATA VIRTUAL,`offset` BIGINT METADATA VIRTUAL,
id int, 
ts bigint , 
vc int )
WITH ('connector' = 'kafka','properties.bootstrap.servers' = 'node2:9092,node3:9092,node4:9094','properties.group.id' = 'test',
-- 'earliest-offset', 'latest-offset', 'group-offsets', 'timestamp' and 'specific-offsets''scan.startup.mode' = 'earliest-offset',-- fixed为flink实现的分区器，一个并行度只写往kafka一个分区
'sink.partitioner' = 'fixed','topic' = 'ws1','format' = 'json'
);

可以往kafka读数据，也可以往kafka写数据。

插入数据到Kafka表

如果没有source表，先创建source表，如果source表存在则不需要再创建。

CREATE TABLE source ( id INT, ts BIGINT, vc INT
) WITH ( 'connector' = 'datagen', 'rows-per-second'='1', 'fields.id.kind'='random', 'fields.id.min'='1', 'fields.id.max'='10', 'fields.ts.kind'='sequence', 'fields.ts.start'='1', 'fields.ts.end'='1000000', 'fields.vc.kind'='random', 'fields.vc.min'='1', 'fields.vc.max'='100'
);

把source表插入t1表

insert into t1(id,ts,vc) select * from source;

如果报错

[ERROR] Could not execute SQL statement. Reason:
java.lang.ClassNotFoundException: org.apache.kafka.common.serialization.ByteArraySerializer

依然同样错误，还不行，把kafka libs目录下的kafka-clients-3.3.1.jar，把jar包发到Flink的lib目录，同时也注意重启sql-client、yarn-session也要重启（重要）

cp $KAFKA_HOME/libs/kafka-clients-3.3.1.jar $FLINK_HOME/lib

查看是否复制成功

$ ls $FLINK_HOME/lib

重启sql-client重新操作，成功如下：

Flink SQL> CREATE TABLE t1( 
>   `event_time` TIMESTAMP(3) METADATA FROM 'timestamp',
>   --列名和元数据名一致可以省略 FROM 'xxxx', VIRTUAL表示只读
>   `partition` BIGINT METADATA VIRTUAL,
>   `offset` BIGINT METADATA VIRTUAL,
> id int, 
> ts bigint , 
> vc int )
> WITH (
>   'connector' = 'kafka',
>   'properties.bootstrap.servers' = 'node2:9092,node3:9092,node4:9094',
>   'properties.group.id' = 'test',
> -- 'earliest-offset', 'latest-offset', 'group-offsets', 'timestamp' and 'specific-offsets'
>   'scan.startup.mode' = 'earliest-offset',
>   -- fixed为flink实现的分区器，一个并��度只写往kafka一个分区
> 'sink.partitioner' = 'fixed',
>   'topic' = 'ws1',
>   'format' = 'json'
> );
[INFO] Execute statement succeed.
​
Flink SQL> CREATE TABLE source ( 
>     id INT, 
>     ts BIGINT, 
>     vc INT
> ) WITH ( 
>     'connector' = 'datagen', 
>     'rows-per-second'='1', 
>     'fields.id.kind'='random', 
>     'fields.id.min'='1', 
>     'fields.id.max'='10', 
>     'fields.ts.kind'='sequence', 
>     'fields.ts.start'='1', 
>     'fields.ts.end'='1000000', 
>     'fields.vc.kind'='random', 
>     'fields.vc.min'='1', 
>     'fields.vc.max'='100'
> );
[INFO] Execute statement succeed.
​
Flink SQL> insert into t1(id,ts,vc) select * from source;2024-06-14 10:45:30,125 WARN  org.apache.flink.yarn.configuration.YarnLogConfigUtil        [] - The configuration directory ('/home/hadoop/soft/flink-1.17.1/conf') already contains a LOG4J config file.If you want to use logback, then please delete or rename the log configuration file.
2024-06-14 10:45:30,673 INFO  org.apache.hadoop.yarn.client.RMProxy                        [] - Connecting to ResourceManager at node3/192.168.193.143:8032
2024-06-14 10:45:31,027 INFO  org.apache.flink.yarn.YarnClusterDescriptor                  [] - No path for the flink jar passed. Using the location of class org.apache.flink.yarn.YarnClusterDescriptor to locate the jar
2024-06-14 10:45:31,227 INFO  org.apache.flink.yarn.YarnClusterDescriptor                  [] - Found Web Interface node3:41749 of application 'application_1718331886020_0001'.
insert into t1(id,ts,vc) select * from source;
[INFO] Submitting SQL update statement to the cluster...
[INFO] SQL update statement has been successfully submitted to the cluster:
Job ID: b1765f969c3ae637bd4c8100efbb0c4e
​

查询Kafka表

select * from t1;

报错

[ERROR] Could not execute SQL statement. Reason:
java.lang.ClassNotFoundException: org.apache.kafka.clients.consumer.ConsumerRecord​

重启yarn session，重新操作，成功如下：

Flink SQL> CREATE TABLE t1( 
>   `event_time` TIMESTAMP(3) METADATA FROM 'timestamp',
>   --列名和元数据名一致可以省略 FROM 'xxxx', VIRTUAL表示只读
>   `partition` BIGINT METADATA VIRTUAL,
>   `offset` BIGINT METADATA VIRTUAL,
> id int, 
> ts bigint , 
> vc int )
> WITH (
>   'connector' = 'kafka',
>   'properties.bootstrap.servers' = 'node2:9092,node3:9092,node4:9094',
>   'properties.group.id' = 'test',
> -- 'earliest-offset', 'latest-offset', 'group-offsets', 'timestamp' and 'specific-offsets'
>   'scan.startup.mode' = 'earliest-offset',
>   -- fixed为flink实现的分区器，一个并??度只写往kafka一个分区
> 'sink.partitioner' = 'fixed',
>   'topic' = 'ws1',
>   'format' = 'json'
> );
[INFO] Execute statement succeed.
​
Flink SQL> CREATE TABLE source ( 
>     id INT, 
>     ts BIGINT, 
>     vc INT
> ) WITH ( 
>     'connector' = 'datagen', 
>     'rows-per-second'='1', 
>     'fields.id.kind'='random', 
>     'fields.id.min'='1', 
>     'fields.id.max'='10', 
>     'fields.ts.kind'='sequence', 
>     'fields.ts.start'='1', 
>     'fields.ts.end'='1000000', 
>     'fields.vc.kind'='random', 
>     'fields.vc.min'='1', 
>     'fields.vc.max'='100'
> );
[INFO] Execute statement succeed.
​
Flink SQL> insert into t1(id,ts,vc) select * from source;2024-06-14 11:22:17,971 WARN  org.apache.flink.yarn.configuration.YarnLogConfigUtil        [] - The configuration directory ('/home/hadoop/soft/flink-1.17.1/conf') already contains a LOG4J config file.If you want to use logback, then please delete or rename the log configuration file.
2024-06-14 11:22:18,422 INFO  org.apache.hadoop.yarn.client.RMProxy                        [] - Connecting to ResourceManager at node3/192.168.193.143:8032
2024-06-14 11:22:18,895 INFO  org.apache.flink.yarn.YarnClusterDescriptor                  [] - No path for the flink jar passed. Using the location of class org.apache.flink.yarn.YarnClusterDescriptor to locate the jar
2024-06-14 11:22:19,052 INFO  org.apache.flink.yarn.YarnClusterDescriptor                  [] - Found Web Interface node4:38788 of application 'application_1718331886020_0002'.
insert into t1(id,ts,vc) select * from source;
[INFO] Submitting SQL update statement to the cluster...
[INFO] SQL update statement has been successfully submitted to the cluster:
Job ID: 84292f84d1fce4756ccd8ae294b6163a
​
​
Flink SQL> select * from t1;2024-06-14 11:23:38,338 WARN  org.apache.flink.yarn.configuration.YarnLogConfigUtil        [] - The configuration directory ('/home/hadoop/soft/flink-1.17.1/conf') already contains a LOG4J config file.If you want to use logback, then please delete or rename the log configuration file.
2024-06-14 11:23:38,606 INFO  org.apache.hadoop.yarn.client.RMProxy                        [] - Connecting to ResourceManager at node3/192.168.193.143:8032
2024-06-14 11:23:38,617 INFO  org.apache.flink.yarn.YarnClusterDescriptor                  [] - No path for the flink jar passed. Using the location of class org.apache.flink.yarn.YarnClusterDescriptor to locate the jar
2024-06-14 11:23:38,649 INFO  org.apache.flink.yarn.YarnClusterDescriptor                  [] - Found Web Interface node4:38788 of application 'application_1718331886020_0002'.
select * from t1;
[INFO] Result retrieval cancelled.
​
Flink SQL> 
​

 

upsert-kafka表

'connector' = 'upsert-kafka'

如果当前表存在更新操作，那么普通的kafka连接器将无法满足，此时可以使用Upsert Kafka连接器。

创建upsert-kafka的映射表(必须定义主键)

CREATE TABLE t2( id int , sumVC int ,primary key (id) NOT ENFORCED 
)
WITH ('connector' = 'upsert-kafka','properties.bootstrap.servers' = 'node2:9092','topic' = 'ws2','key.format' = 'json','value.format' = 'json'
);

如果没有kafka名为ws2的topic，将自动被创建。

插入upsert-kafka表

insert into t2 select id,sum(vc) sumVC  from source group by id;

查询upsert-kafka表

upsert-kafka 无法从指定的偏移量读取，只会从主题的源读取。如此，才知道整个数据的更新过程。并且通过 -U，+U，+I 等符号来显示数据的变化过程。

设置显示模式

SET sql-client.execution.result-mode=tableau;

 查询t2表数据

select * from t2;

如果发现没有输出数据，原因是之前的source表已经生成到end（1000000）就不再生成数据了。

进入Flink Web UI，cancel掉所有running job，重新操作成功如下：

删除表

Flink SQL> show tables;
+------------+
| table name |
+------------+
|     source |
|         t1 |
|         t2 |
+------------+
3 rows in set
​
Flink SQL> drop table source;
Flink SQL> drop table t1;
Flink SQL> drop table t2;

创建表

CREATE TABLE source ( id INT, ts BIGINT, vc INT
) WITH ( 'connector' = 'datagen', 'rows-per-second'='1', 'fields.id.kind'='random', 'fields.id.min'='1', 'fields.id.max'='10', 'fields.ts.kind'='sequence', 'fields.ts.start'='1', 'fields.ts.end'='1000000', 'fields.vc.kind'='random', 'fields.vc.min'='1', 'fields.vc.max'='100'
);

CREATE TABLE t2( id int , sumVC int ,primary key (id) NOT ENFORCED 
)
WITH ('connector' = 'upsert-kafka','properties.bootstrap.servers' = 'node2:9092','topic' = 'ws2','key.format' = 'json','value.format' = 'json'
);

设置显示模式

SET sql-client.execution.result-mode=tableau;

查询表

select * from t2;

 

完成！enjoy it!