DATAREDIS-580 - Support Master/Slave connections with ReadFrom settings using Lettuce.

We now allow configuration of ReadFrom settings using the Lettuce driver to enable slave reads. If ReadFrom is configured, we opt-in to Master/Slave connections instead of plain connections. Master/Slave connections route commands to the configured type of node depending on whether the command is a read or write command.

LettuceClientConfiguration configuration = LettuceClientConfiguration.builder().readFrom(ReadFrom.SLAVE).build();

ReadFrom is available for:

* Static Master/Slave Redis without Redis Sentinel
* Sentinel-Managed Master/Slave Redis
* Redis Cluster

ReadFrom is not configured for Pub/Sub connections or connections to the actual Sentinel servers.

Original Pull Request: #287

src/test/java/org/springframework/data/redis/connection/lettuce/LettuceConnectionFactoryTests.java

@@ -23,6 +23,7 @@ import static org.junit.Assume.*;
 
 import io.lettuce.core.EpollProvider;
 import io.lettuce.core.KqueueProvider;
+import io.lettuce.core.ReadFrom;
 import io.lettuce.core.RedisException;
 import io.lettuce.core.api.async.RedisAsyncCommands;
 import io.lettuce.core.api.reactive.BaseRedisReactiveCommands;
@@ -385,6 +386,28 @@ public class LettuceConnectionFactoryTests {
 		factory.destroy();
 	}
 
+	@Test // DATAREDIS-580
+	public void factoryUsesMasterSlaveConnections() {
+
+		LettuceClientConfiguration configuration = LettuceTestClientConfiguration.builder().readFrom(ReadFrom.SLAVE)
+				.build();
+
+		LettuceConnectionFactory factory = new LettuceConnectionFactory(SettingsUtils.standaloneConfiguration(),
+				configuration);
+		factory.afterPropertiesSet();
+
+		RedisConnection connection = factory.getConnection();
+
+		try {
+			assertThat(connection.ping(), is(equalTo("PONG")));
+			assertThat(connection.info().getProperty("role"), is(equalTo("slave")));
+		} finally {
+			this.connection.close();
+		}
+
+		factory.destroy();
+	}
+
 	@Test // DATAREDIS-576
 	public void connectionAppliesClientName() {
 

src/test/java/org/springframework/data/redis/connection/lettuce/LettuceReactiveClusterCommandsTestsBase.java

@@ -22,6 +22,8 @@ import io.lettuce.core.api.sync.RedisCommands;
 import io.lettuce.core.cluster.api.sync.RedisAdvancedClusterCommands;
 import io.lettuce.core.cluster.api.sync.RedisClusterCommands;
 
+import java.util.Optional;
+
 import org.junit.After;
 import org.junit.Before;
 import org.junit.ClassRule;
@@ -43,7 +45,8 @@ public abstract class LettuceReactiveClusterCommandsTestsBase {
 		assumeThat(clientProvider.test(), is(true));
 		nativeCommands = clientProvider.getClient().connect().sync();
 		connection = new LettuceReactiveRedisClusterConnection(
-				new ClusterConnectionProvider(clientProvider.getClient(), LettuceReactiveRedisConnection.CODEC),
+				new ClusterConnectionProvider(clientProvider.getClient(), LettuceReactiveRedisConnection.CODEC,
+						Optional.empty()),
 				clientProvider.getClient());
 	}
 

src/test/java/org/springframework/data/redis/connection/lettuce/LettuceReactiveCommandsTestsBase.java

@@ -26,6 +26,7 @@ import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 import org.junit.After;
 import org.junit.Before;
@@ -89,9 +90,9 @@ public abstract class LettuceReactiveCommandsTestsBase {
 		List<Object[]> parameters = new ArrayList<>();
 
 		StandaloneConnectionProvider standaloneProvider = new StandaloneConnectionProvider(standalone.getClient(),
-				LettuceReactiveRedisConnection.CODEC);
+				LettuceReactiveRedisConnection.CODEC, Optional.empty());
 		StandaloneConnectionProvider nativeConnectionProvider = new StandaloneConnectionProvider(standalone.getClient(),
-				StringCodec.UTF8);
+				StringCodec.UTF8, Optional.empty());
 
 		parameters.add(new Object[] { standaloneProvider, nativeConnectionProvider, "Standalone" });
 		parameters.add(new Object[] {
@@ -101,9 +102,9 @@ public abstract class LettuceReactiveCommandsTestsBase {
 		if (cluster.test()) {
 
 			ClusterConnectionProvider clusterProvider = new ClusterConnectionProvider(cluster.getClient(),
-					LettuceReactiveRedisConnection.CODEC);
+					LettuceReactiveRedisConnection.CODEC, Optional.empty());
 			ClusterConnectionProvider nativeClusterConnectionProvider = new ClusterConnectionProvider(cluster.getClient(),
-					StringCodec.UTF8);
+					StringCodec.UTF8, Optional.empty());
 
 			parameters.add(new Object[] { clusterProvider, nativeClusterConnectionProvider, "Cluster" });
 		}

src/test/java/org/springframework/data/redis/connection/lettuce/LettuceSentinelIntegrationTests.java

@@ -20,6 +20,8 @@ import static org.hamcrest.core.Is.is;
 import static org.hamcrest.core.IsEqual.equalTo;
 import static org.junit.Assert.*;
 
+import io.lettuce.core.ReadFrom;
+
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -33,8 +35,10 @@ import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 import org.junit.runners.Parameterized.Parameters;
 import org.springframework.data.redis.ConnectionFactoryTracker;
+import org.springframework.data.redis.SettingsUtils;
 import org.springframework.data.redis.connection.AbstractConnectionIntegrationTests;
 import org.springframework.data.redis.connection.DefaultStringRedisConnection;
+import org.springframework.data.redis.connection.RedisConnection;
 import org.springframework.data.redis.connection.RedisSentinelConfiguration;
 import org.springframework.data.redis.connection.RedisSentinelConnection;
 import org.springframework.data.redis.connection.RedisServer;
@@ -170,4 +174,64 @@ public class LettuceSentinelIntegrationTests extends AbstractConnectionIntegrati
 			connection.close();
 		}
 	}
+
+	@Test // DATAREDIS-580
+	public void factoryWithReadFromMasterSettings() {
+
+		LettuceConnectionFactory factory = new LettuceConnectionFactory(SENTINEL_CONFIG,
+				LettuceTestClientConfiguration.builder().readFrom(ReadFrom.MASTER).build());
+		factory.afterPropertiesSet();
+
+		ConnectionFactoryTracker.add(factory);
+
+		StringRedisConnection connection = new DefaultStringRedisConnection(factory.getConnection());
+
+		try {
+			assertThat(connection.ping(), is(equalTo("PONG")));
+			assertThat(connection.info().getProperty("role"), is(equalTo("master")));
+		} finally {
+			connection.close();
+		}
+	}
+
+	@Test // DATAREDIS-580
+	public void factoryWithReadFromSlaveSettings() {
+
+		LettuceConnectionFactory factory = new LettuceConnectionFactory(SENTINEL_CONFIG,
+				LettuceTestClientConfiguration.builder().readFrom(ReadFrom.SLAVE).build());
+		factory.afterPropertiesSet();
+
+		ConnectionFactoryTracker.add(factory);
+
+		StringRedisConnection connection = new DefaultStringRedisConnection(factory.getConnection());
+
+		try {
+			assertThat(connection.ping(), is(equalTo("PONG")));
+			assertThat(connection.info().getProperty("role"), is(equalTo("slave")));
+		} finally {
+			connection.close();
+		}
+	}
+
+	@Test // DATAREDIS-580
+	public void factoryUsesMasterSlaveConnections() {
+
+		LettuceClientConfiguration configuration = LettuceTestClientConfiguration.builder().readFrom(ReadFrom.SLAVE)
+				.build();
+
+		LettuceConnectionFactory factory = new LettuceConnectionFactory(SettingsUtils.standaloneConfiguration(),
+				configuration);
+		factory.afterPropertiesSet();
+
+		RedisConnection connection = factory.getConnection();
+
+		try {
+			assertThat(connection.ping(), is(equalTo("PONG")));
+			assertThat(connection.info().getProperty("role"), is(equalTo("slave")));
+		} finally {
+			this.connection.close();
+		}
+
+		factory.destroy();
+	}
 }

src/test/java/org/springframework/data/redis/test/util/RedisClusterRule.java

@@ -17,6 +17,8 @@ package org.springframework.data.redis.test.util;
 
 import static org.hamcrest.CoreMatchers.*;
 
+import redis.clients.jedis.Jedis;
+
 import org.junit.Assume;
 import org.junit.rules.ExternalResource;
 import org.junit.rules.TestRule;
@@ -24,8 +26,6 @@ import org.springframework.data.redis.connection.RedisClusterConfiguration;
 import org.springframework.data.redis.connection.RedisNode;
 import org.springframework.data.redis.connection.jedis.JedisConverters;
 
-import redis.clients.jedis.Jedis;
-
 /**
  * Simple {@link TestRule} implementation that check Redis is running in cluster mode.
  * 
@@ -59,7 +59,7 @@ public class RedisClusterRule extends ExternalResource {
 	 * @see org.junit.rules.ExternalResource#before()
 	 */
 	@Override
-	protected void before() throws Throwable {
+	public void before() {
 		Assume.assumeThat(mode, is("cluster"));
 	}