Create Apache Kafka® table on Apache Flink® on HDInsight on AKS

Using this example, learn how to Create Kafka table on Apache FlinkSQL.

Prerequisites

• Apache Kafka cluster on HDInsight
• Apache Flink cluster on HDInsight on AKS

Kafka SQL connector on Apache Flink

The Kafka connector allows for reading data from and writing data into Kafka topics. For more information, refer Apache Kafka SQL Connector.

Create a Kafka table on Flink SQL

Prepare topic and data on HDInsight Kafka

Prepare messages with weblog.py

import random
import json
import time
from datetime import datetime

user_set = [
        'John',
        'XiaoMing',
        'Mike',
        'Tom',
        'Machael',
        'Zheng Hu',
        'Zark',
        'Tim',
        'Andrew',
        'Pick',
        'Sean',
        'Luke',
        'Chunck'
]

web_set = [
        'https://google.com',
        'https://facebook.com?id=1',
        'https://tmall.com',
        'https://baidu.com',
        'https://taobao.com',
        'https://aliyun.com',
        'https://apache.com',
        'https://flink.apache.com',
        'https://hbase.apache.com',
        'https://github.com',
        'https://gmail.com',
        'https://stackoverflow.com',
        'https://python.org'
]

def main():
        while True:
                if random.randrange(10) < 4:
                        url = random.choice(web_set[:3])
                else:
                        url = random.choice(web_set)

                log_entry = {
                        'userName': random.choice(user_set),
                        'visitURL': url,
                        'ts': datetime.now().strftime("%m/%d/%Y %H:%M:%S")
                }

                print(json.dumps(log_entry))
                time.sleep(0.05)

if __name__ == "__main__":
    main()

Pipeline to Kafka topic

sshuser@hn0-contsk:~$ python weblog.py | /usr/hdp/current/kafka-broker/bin/kafka-console-producer.sh --bootstrap-server wn0-contsk:9092 --topic click_events

Other commands:

-- create topic
/usr/hdp/current/kafka-broker/bin/kafka-topics.sh --create --replication-factor 2 --partitions 3 --topic click_events --bootstrap-server wn0-contsk:9092

-- delete topic
/usr/hdp/current/kafka-broker/bin/kafka-topics.sh --delete  --topic click_events --bootstrap-server wn0-contsk:9092

-- consume topic
sshuser@hn0-contsk:~$ /usr/hdp/current/kafka-broker/bin/kafka-console-consumer.sh --bootstrap-server wn0-contsk:9092 --topic click_events --from-beginning
{"userName": "Luke", "visitURL": "https://flink.apache.com", "ts": "06/26/2023 14:33:43"}
{"userName": "Tom", "visitURL": "https://stackoverflow.com", "ts": "06/26/2023 14:33:43"}
{"userName": "Chunck", "visitURL": "https://google.com", "ts": "06/26/2023 14:33:44"}
{"userName": "Chunck", "visitURL": "https://facebook.com?id=1", "ts": "06/26/2023 14:33:44"}
{"userName": "John", "visitURL": "https://tmall.com", "ts": "06/26/2023 14:33:44"}
{"userName": "Andrew", "visitURL": "https://facebook.com?id=1", "ts": "06/26/2023 14:33:44"}
{"userName": "John", "visitURL": "https://tmall.com", "ts": "06/26/2023 14:33:44"}
{"userName": "Pick", "visitURL": "https://google.com", "ts": "06/26/2023 14:33:44"}
{"userName": "Mike", "visitURL": "https://tmall.com", "ts": "06/26/2023 14:33:44"}
{"userName": "Zheng Hu", "visitURL": "https://tmall.com", "ts": "06/26/2023 14:33:44"}
{"userName": "Luke", "visitURL": "https://facebook.com?id=1", "ts": "06/26/2023 14:33:44"}
{"userName": "John", "visitURL": "https://flink.apache.com", "ts": "06/26/2023 14:33:44"}

Apache Flink SQL client

Detailed instructions are provided on how to use Secure Shell for Flink SQL client.

Download Kafka SQL Connector & Dependencies into SSH

We're using the Kafka 3.2.0 dependencies in the below step, You're required to update the command based on your Kafka version on HDInsight cluster.

wget https://repo1.maven.org/maven2/org/apache/kafka/kafka-clients/3.2.0/kafka-clients-3.2.0.jar
wget https://repo1.maven.org/maven2/org/apache/flink/flink-connector-kafka/1.17.0/flink-connector-kafka-1.17.0.jar

Connect to Apache Flink SQL Client

Let's now connect to the Flink SQL Client with Kafka SQL client jars.

msdata@pod-0 [ /opt/flink-webssh ]$ bin/sql-client.sh -j flink-connector-kafka-1.17.0.jar -j kafka-clients-3.2.0.jar

Create Kafka table on Apache Flink SQL

Let's create the Kafka table on Flink SQL, and select the Kafka table on Flink SQL.

You're required to update your Kafka bootstrap server IPs in the below snippet.

CREATE TABLE KafkaTable (
`userName` STRING,
`visitURL` STRING,
`ts` TIMESTAMP(3) METADATA FROM 'timestamp'
) WITH (
'connector' = 'kafka',
'topic' = 'click_events',
'properties.bootstrap.servers' = '<update-kafka-bootstrapserver-ip>:9092,<update-kafka-bootstrapserver-ip>:9092,<update-kafka-bootstrapserver-ip>:9092',
'properties.group.id' = 'my_group',
'scan.startup.mode' = 'earliest-offset',
'format' = 'json'
);

select * from KafkaTable;

Produce Kafka messages

Let's now produce Kafka messages to the same topic, using HDInsight Kafka.

python weblog.py | /usr/hdp/current/kafka-broker/bin/kafka-console-producer.sh --bootstrap-server wn0-contsk:9092 --topic click_events

Table on Apache Flink SQL

You can monitor the table on Flink SQL.

Here are the streaming jobs on Flink Web UI.

Reference

• Apache Kafka SQL Connector
• Apache, Apache Kafka, Kafka, Apache Flink, Flink, and associated open source project names are trademarks of the Apache Software Foundation (ASF).