feat: 컨슈머 워커 스레드 기능 구현

- 오프셋 비동기 커밋 & 예외 처리 & shutdown 기능 구현

src/main/java/com/sangdol/consumer/infrastructure/kafka/consumer/ConsumerWorker.java

@@ -0,0 +1,87 @@
+package com.sangdol.consumer.infrastructure.kafka.consumer;
+
+import java.time.Duration;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
+
+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.clients.consumer.OffsetAndMetadata;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.errors.WakeupException;
+
+import com.sangdol.consumer.domain.TestRecord;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+@RequiredArgsConstructor
+public class ConsumerWorker implements Runnable {
+
+	private final KafkaConsumer<String, TestRecord> consumer;
+	private final RecordProcessor recordProcessor;
+	private final AtomicBoolean running = new AtomicBoolean(true);
+
+	@Override
+	public void run() {
+		try {
+			log.info("[ConsumerWorker] started. thread: {}", Thread.currentThread().getName());
+			while (running.get()) {
+				ConsumerRecords<String, TestRecord> records = consumer.poll(Duration.ofMillis(1000));
+
+				if (records.isEmpty()) {
+					recordProcessor.processIfEmptyRecords();
+					continue;
+				}
+
+				log.debug("[ConsumerWorker] received {} records. thread: {}", records.count(), Thread.currentThread().getName());
+				recordProcessor.process(records);
+				commitAsync(records);
+			}
+		} catch (WakeupException e) {
+			log.info("[ConsumerWorker] Wakeup Exception. thread: {}", Thread.currentThread().getName());
+		} catch (Exception e) {
+			log.info("[ConsumerWorker] Unexpected Exception. thread: {}", Thread.currentThread().getName());
+		} finally {
+			try {
+				consumer.commitSync();
+				log.info("[ConsumerWorker] Final offset committed. Close consumer.. ");
+			} catch (Exception e) {
+				log.error("[ConsumerWorker] Failed to commit final offsets when shutdown. thread: {}",
+					Thread.currentThread().getName());
+			} finally {
+				consumer.close();
+				log.info("[ConsumerWorker] Closed consumer thread. thread: {}", Thread.currentThread().getName());
+			}
+		}
+	}
+
+	private void commitAsync(ConsumerRecords<String, TestRecord> records) {
+		Map<TopicPartition, OffsetAndMetadata> offsets = records.partitions().stream()
+			.collect(Collectors.toMap(tp -> tp, tp -> {
+				List<ConsumerRecord<String, TestRecord>> partitionRecords = records.records(tp);
+				long lastOffset = partitionRecords.get(partitionRecords.size() - 1).offset();
+
+				return new OffsetAndMetadata(lastOffset + 1);
+			}));
+
+		consumer.commitAsync(offsets, (o, exception) -> {
+			if (exception != null) {
+				log.error("[ConsumerWorker] failed to commit offsets for offset: {}, partition {}", o,
+					records.partitions(), exception);
+			} else {
+				log.debug("[ConsumerWorker] committed offsets for offset: {}, partition {}", o,
+					records.partitions());
+			}
+		});
+	}
+
+	public void shutdown() {
+		running.set(false);
+		consumer.wakeup();
+	}
+}