Install Kafka in WSL and access from Windows

1. install Kafka in WSL
   quickstart
2. Access Kafka with Java from Windows
   dependence：org.apache.kafka-clients:3.1.2

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringSerializer;

import java.util.Properties;

public class ProducerDemo {

  public static void main(String[] args) {

    String bootstrapServers = "127.0.0.1:9092";

    //create Producer properties
    Properties properties = new Properties();
    properties.setProperty(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
    properties.setProperty(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG,
        StringSerializer.class.getName());
    properties.setProperty(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG,
        StringSerializer.class.getName());

    //create the producer
    KafkaProducer<String, String> producer = new KafkaProducer<String, String>(properties);

    //create a producer record
    ProducerRecord<String, String> record =
        new ProducerRecord<String, String>("local.chat", "hallo world!!!!");

    //send data
    producer.send(record);

    //flush + close
    producer.flush();
    producer.close();
  }

}

よくある問題

Error1

2022-12-13 17:41:10.884 WARN 23284 --- [ad | producer-1] org.apache.kafka.clients.NetworkClient : [Producer clientId=producer-1] Con
nection to node -1 (/172.21.223.255:9092) could not be established. Broker may not be available.
2022-12-13 17:41:10.884 WARN 23284 --- [ad | producer-1] org.apache.kafka.clients.NetworkClient : [Producer clientId=producer-1] Boo
tstrap broker 172.21.223.255:9092 (id: -1 rack: null) disconnected

解決方法：
(1)

WSL2 currently has a networking issue that prevents outside programs to connect to Kafka running on WSL2 (for example your Java programs, Conduktor, etc...);
Disable IPv6 on WSL2
sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1

(2) cd {Kafka_Home}
vim config/server.properites
下記のものを追加する

advertised.listeners=PLAINTEXT://127.0.0.1:9092
listener.security.protocol.map=PLAINTEXT:PLAINTEXT
listeners=PLAINTEXT://0.0.0.0:9092

(3) 再起動

Error2

bin/kafka-server-start.sh config/kraft/server.propertiesを実行する時

[2022-12-13 22:45:29,548] ERROR Exiting Kafka due to fatal exception (kafka.Kafka$)
org.apache.kafka.common.KafkaException: No meta.properties found in /tmp/kraft-combined-logs (have you run kafka-storage.sh to format the directory?)

解決方法

rand=`./bin/kafka-storage.sh random-uuid`
echo $rand
./bin/kafka-storage.sh format -t $rand  -c ./config/kraft/server.properties

再起動
bin/kafka-server-start.sh config/kraft/server.properties