개발자의 일상

참고

 - https://aws.amazon.com/ko/blogs/database/optimize-redis-client-performance-for-amazon-elasticache/

 - https://aws.amazon.com/ko/blogs/database/best-practices-redis-clients-and-amazon-elasticache-for-redis/

 - https://github.com/lettuce-io/lettuce-core/wiki/Connection-Pooling

 - https://lettuce.io/core/release/reference/#connection-pooling.is-connection-pooling-necessary

1. 필요 라이브러리
   1. maven dependency 추가

<dependency>
    <groupId>io.lettuce</groupId>
    <artifactId>lettuce-core</artifactId>
    <version>5.3.3.RELEASE</version>
</dependency>


<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
    <version>2.8.1</version>
</dependency>

2. 샘플 소스 - java

 - async command 등 참고 링크

import io.lettuce.core.ClientOptions;
import io.lettuce.core.RedisClient;
import io.lettuce.core.RedisConnectionException;
import io.lettuce.core.api.StatefulRedisConnection;
import io.lettuce.core.cluster.ClusterClientOptions;
import io.lettuce.core.cluster.RedisClusterClient;
import io.lettuce.core.cluster.api.StatefulRedisClusterConnection;
import io.lettuce.core.support.ConnectionPoolSupport;
import org.apache.commons.pool2.impl.GenericObjectPool;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;

/**
 * redis 커넥션풀 기반 연결 샘플
 *
 * @author 
 */
public class ConnectionSampleWithPool {

	private static final String REDIS_CON_URL = "redis://192.168.56.1:6379/0"; //로컬 redis 0번 사용
	public static GenericObjectPool<StatefulRedisConnection<String, String>> pool = null; //sync & 비 클러스터모드 커넥션풀

	public static void main(String[] args) throws InterruptedException {

		pool = nonClusterPoolUsage();
		//pool = useClusterPoolUsage(); //클러스터모드일때

		testSetValue("key-pool-test-1", "key-pool-test-1");
		testSetValue("key-pool-test-2", "key-pool-test-2");
		testSetValue("key-pool-test-3", "key-pool-test-3");

		Thread.sleep(10 * 1000); //커넥션풀 close 전에 대기 후, redis-cli(서버)에서 client list 명령어로 현재 연결된 클라이언트 리스트를 확인해보면 됨

		pool.close();
		System.out.println("finish");
	}

	/**
	 * set value 테스트
	 *
	 * @param key
	 * @param value
	 */
	private static void testSetValue(String key, String value) {

		try (StatefulRedisConnection<String, String> connection = pool.borrowObject()) { //pool을 이용해서 커맨드 실행
			connection.sync().set(key, value);
			value = connection.sync().get(key);
			System.out.println(value);
		} catch (RedisConnectionException e) {
			System.out.println(String.format("Failed to connect to Redis server: %s", e));
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * 비 클러스터 모드일때 커넥션풀 셋팅
	 *
	 * @return
	 */
	private static GenericObjectPool<StatefulRedisConnection<String, String>> nonClusterPoolUsage() {

		RedisClient client = RedisClient.create(REDIS_CON_URL);
		client.setOptions(ClientOptions.builder().autoReconnect(true).build());

		return ConnectionPoolSupport.createGenericObjectPool(() -> client.connect(), createPoolConfig());
	}

	/**
	 * 클러스터모드일때 커넥션 풀 셋팅
	 *  - 참고: https://github.com/Azure/azure-redis-cache-samples/blob/master/Java/ClientSamples/src/main/java/lettuce/PoolUsage.java
	 *
	 * @return
	 */
	private static GenericObjectPool<StatefulRedisClusterConnection<String, String>> useClusterPoolUsage() {

		RedisClusterClient clusterClient = RedisClusterClient.create(REDIS_CON_URL);
		clusterClient.setOptions(ClusterClientOptions.builder().autoReconnect(true).build());

		return ConnectionPoolSupport.createGenericObjectPool(() -> clusterClient.connect(), createPoolConfig());
	}

	/**
	 * 커넥션풀 설정 생성
	 *
	 * @return
	 */
	private static GenericObjectPoolConfig createPoolConfig() {

		GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();

		poolConfig.setMaxTotal(20);
		poolConfig.setMaxIdle(10);

		// "true" will result better behavior when unexpected load hits in production
		// "false" makes it easier to debug when your maxTotal/minIdle/etc settings need adjusting.
		poolConfig.setBlockWhenExhausted(true);
		poolConfig.setMaxWaitMillis(1000);
		poolConfig.setMinIdle(5);

		return poolConfig;
	}

}