package de.juplo.kafka;
+import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
-import org.apache.kafka.clients.consumer.KafkaConsumer;
-import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.kafka.common.errors.WakeupException;
import java.time.Duration;
import java.util.Arrays;
-import java.util.Properties;
+import java.util.concurrent.Callable;
@Slf4j
-public class SimpleConsumer
+@RequiredArgsConstructor
+public class SimpleConsumer implements Callable<Integer>
{
private final String id;
private final String topic;
- private final KafkaConsumer<String, String> consumer;
+ private final Consumer<String, String> consumer;
private long consumed = 0;
- private volatile boolean running = true;
- private volatile boolean done = false;
-
- public SimpleConsumer(String broker, String topic, String groupId, String clientId)
- {
- Properties props = new Properties();
- props.put("bootstrap.servers", broker);
- props.put("group.id", groupId); // ID für die Offset-Commits
- props.put("client.id", clientId); // Nur zur Wiedererkennung
- props.put("partition.assignment.strategy", "org.apache.kafka.clients.consumer.CooperativeStickyAssignor");
- props.put("key.deserializer", StringDeserializer.class.getName());
- props.put("value.deserializer", StringDeserializer.class.getName());
-
- consumer = new KafkaConsumer<>(props);
-
- this.topic = topic;
- this.id = clientId;
- }
- public void run()
+ @Override
+ public Integer call()
{
try
{
- log.info("{} - Subscribing to topic test", id);
- consumer.subscribe(Arrays.asList("test"));
+ log.info("{} - Subscribing to topic {}", id, topic);
+ consumer.subscribe(Arrays.asList(topic));
- while (running)
+ while (true)
{
ConsumerRecords<String, String> records =
consumer.poll(Duration.ofSeconds(1));
log.info("{} - Received {} messages", id, records.count());
for (ConsumerRecord<String, String> record : records)
{
- consumed++;
- log.info(
- "{} - {}: {}/{} - {}={}",
- id,
- record.offset(),
- record.topic(),
- record.partition(),
- record.key(),
- record.value()
- );
+ handleRecord(
+ record.topic(),
+ record.partition(),
+ record.offset(),
+ record.key(),
+ record.value());
}
}
}
+ catch(WakeupException e)
+ {
+ log.info("{} - Consumer was signaled to finish its work", id);
+ return 0;
+ }
catch(Exception e)
{
- log.error("{} - Unexpected error: {}", id, e.toString());
+ log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
+ consumer.unsubscribe();
+ return 1;
}
finally
{
log.info("{} - Closing the KafkaConsumer", id);
consumer.close();
log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
- done = true;
}
}
-
- public static void main(String[] args) throws Exception
+ private void handleRecord(
+ String topic,
+ Integer partition,
+ Long offset,
+ String key,
+ Message value)
{
- String broker = ":9092";
- String topic = "test";
- String groupId = "my-group";
- String clientId = "DEV";
-
- switch (args.length)
- {
- case 4:
- clientId = args[3];
- case 3:
- groupId = args[2];
- case 2:
- topic = args[1];
- case 1:
- broker = args[0];
- }
-
-
- SimpleConsumer instance = new SimpleConsumer(broker, topic, groupId, clientId);
-
- Runtime.getRuntime().addShutdownHook(new Thread(() ->
- {
- instance.running = false;
- while (!instance.done)
- {
- log.info("Waiting for main-thread...");
- try
- {
- Thread.sleep(1000);
- }
- catch (InterruptedException e) {}
- }
- log.info("Shutdown completed.");
- }));
-
- log.info(
- "Running SimpleConsumer: broker={}, topic={}, group-id={}, client-id={}",
- broker,
- topic,
- groupId,
- clientId);
- instance.run();
+ consumed++;
+ log.info("{} - {}: {}/{} - {}={}", id, offset, topic, partition, key, value);
}
}