DATAREDIS-762 - Add AWS ElastiCache configuration.

We now provide RedisElastiCacheConfiguration to configure connections to AWS ElastiCache for Redis services with optional read replicas.

RedisElastiCacheConfiguration elastiCache = new RedisElastiCacheConfiguration("redis-node-1.elasticache.aws.com")
                                                   .node("redis-node-2.elasticache.aws.com");

LettuceConnectionFactory factory = new LettuceConnectionFactory(elastiCache, configuration);

Original Pull Request: #306

src/test/java/org/springframework/data/redis/connection/RedisElastiCacheConfigurationUnitTests.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.redis.connection;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link RedisElastiCacheConfiguration}.
+ *
+ * @author Mark Paluch
+ */
+public class RedisElastiCacheConfigurationUnitTests {
+
+	@Test // DATAREDIS-762
+	public void shouldCreateSingleHostConfiguration() {
+
+		RedisElastiCacheConfiguration singleHost = new RedisElastiCacheConfiguration("localhost");
+
+		assertThat(singleHost.getNodes()).hasSize(1);
+
+		RedisStandaloneConfiguration node = singleHost.getNodes().get(0);
+
+		assertThat(node.getHostName()).isEqualToIgnoringCase("localhost");
+		assertThat(node.getPort()).isEqualTo(6379);
+	}
+
+	@Test // DATAREDIS-762
+	public void shouldCreateMultiHostConfiguration() {
+
+		RedisElastiCacheConfiguration multiHost = new RedisElastiCacheConfiguration("localhost");
+		multiHost.node("other-host", 6479);
+
+		assertThat(multiHost.getNodes()).hasSize(2);
+
+		RedisStandaloneConfiguration firstNode = multiHost.getNodes().get(0);
+
+		assertThat(firstNode.getHostName()).isEqualToIgnoringCase("localhost");
+		assertThat(firstNode.getPort()).isEqualTo(6379);
+
+		RedisStandaloneConfiguration secondNode = multiHost.getNodes().get(1);
+
+		assertThat(secondNode.getHostName()).isEqualToIgnoringCase("other-host");
+		assertThat(secondNode.getPort()).isEqualTo(6479);
+	}
+
+	@Test // DATAREDIS-762
+	public void shouldApplyPasswordToNodes() {
+
+		RedisElastiCacheConfiguration multiHost = new RedisElastiCacheConfiguration("localhost").node("other-host", 6479);
+
+		multiHost.setPassword(RedisPassword.of("foobar"));
+		multiHost.node("third", 1234);
+
+		assertThat(multiHost.getNodes()).extracting("password").containsExactly(RedisPassword.of("foobar"),
+				RedisPassword.of("foobar"), RedisPassword.of("foobar"));
+	}
+
+	@Test // DATAREDIS-762
+	public void shouldApplyDatabaseToNodes() {
+
+		RedisElastiCacheConfiguration multiHost = new RedisElastiCacheConfiguration("localhost").node("other-host", 6479);
+
+		multiHost.setDatabase(4);
+		multiHost.node("third", 1234);
+
+		assertThat(multiHost.getNodes()).extracting("database").containsExactly(4, 4, 4);
+	}
+}

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

@@ -15,9 +15,7 @@
  */
 package org.springframework.data.redis.connection.lettuce;
 
-import static org.hamcrest.core.Is.*;
-import static org.hamcrest.core.IsEqual.*;
-import static org.hamcrest.core.IsNull.*;
+import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.junit.Assume.*;
 
@@ -43,6 +41,7 @@ import org.springframework.data.redis.RedisSystemException;
 import org.springframework.data.redis.SettingsUtils;
 import org.springframework.data.redis.connection.DefaultStringRedisConnection;
 import org.springframework.data.redis.connection.RedisConnection;
+import org.springframework.data.redis.connection.RedisElastiCacheConfiguration;
 import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
 import org.springframework.data.redis.connection.StringRedisConnection;
 
@@ -386,6 +385,65 @@ public class LettuceConnectionFactoryTests {
 		factory.destroy();
 	}
 
+	@Test // DATAREDIS-762
+	public void factoryUsesElastiCacheMasterSlaveConnections() {
+
+		assumeThat(String.format("No slaves connected to %s:%s.", SettingsUtils.getHost(), SettingsUtils.getPort()),
+				connection.info("replication").getProperty("connected_slaves", "0").compareTo("0") > 0, is(true));
+
+		LettuceClientConfiguration configuration = LettuceTestClientConfiguration.builder().readFrom(ReadFrom.SLAVE)
+				.build();
+
+		RedisElastiCacheConfiguration elastiCache = new RedisElastiCacheConfiguration(SettingsUtils.getHost())
+				.node(SettingsUtils.getHost(), SettingsUtils.getPort() + 1);
+
+		LettuceConnectionFactory factory = new LettuceConnectionFactory(elastiCache,
+				configuration);
+		factory.afterPropertiesSet();
+
+		RedisConnection connection = factory.getConnection();
+
+		try {
+			assertThat(connection.ping(), is(equalTo("PONG")));
+			assertThat(connection.info().getProperty("role"), is(equalTo("slave")));
+		} finally {
+			connection.close();
+		}
+
+		factory.destroy();
+	}
+
+	@Test // DATAREDIS-762
+	public void factoryUsesElastiCacheMasterWithoutMaster() {
+
+		assumeThat(String.format("No slaves connected to %s:%s.", SettingsUtils.getHost(), SettingsUtils.getPort()),
+				connection.info("replication").getProperty("connected_slaves", "0").compareTo("0") > 0, is(true));
+
+		LettuceClientConfiguration configuration = LettuceTestClientConfiguration.builder().readFrom(ReadFrom.MASTER)
+				.build();
+
+		RedisElastiCacheConfiguration elastiCache = new RedisElastiCacheConfiguration(SettingsUtils.getHost(),
+				SettingsUtils.getPort() + 1);
+
+		LettuceConnectionFactory factory = new LettuceConnectionFactory(elastiCache, configuration);
+		factory.afterPropertiesSet();
+
+		RedisConnection connection = factory.getConnection();
+
+		try {
+			connection.ping();
+			fail("Expected RedisException: Master is currently unknown");
+		} catch (RedisSystemException e) {
+
+			assertThat(e.getCause(), is(instanceOf(RedisException.class)));
+			assertThat(e.getCause().getMessage(), containsString("Master is currently unknown"));
+		} finally {
+			connection.close();
+		}
+
+		factory.destroy();
+	}
+
 	@Test // DATAREDIS-580
 	public void factoryUsesMasterSlaveConnections() {