Add ReactiveRedisOperations.listenToLater(…) to await subscriptions.

Original Pull Request: #2052

Author: mp911de

src/main/java/org/springframework/data/redis/core/ReactiveRedisOperations.java

@@ -116,6 +116,49 @@ default Flux<? extends Message<String, V>> listenToPattern(String... patterns) {
 	 */
 	Flux<? extends Message<String, V>> listenTo(Topic... topics);
 
+	/**
+	 * Subscribe to the given Redis {@code channels} and emit {@link Message messages} received for those. The
+	 * {@link Mono} completes once the {@link Topic topic} subscriptions are registered.
+	 *
+	 * @param channels must not be {@literal null}.
+	 * @return a hot sequence of {@link Message messages}.
+	 * @since 2.6
+	 * @see org.springframework.data.redis.listener.ReactiveRedisMessageListenerContainer#receiveLater(ChannelTopic...)
+	 */
+	default Mono<Flux<? extends Message<String, V>>> listenToChannelLater(String... channels) {
+
+		Assert.notNull(channels, "Channels must not be null!");
+
+		return listenToLater(Arrays.stream(channels).map(ChannelTopic::of).toArray(ChannelTopic[]::new));
+	}
+
+	/**
+	 * Subscribe to the Redis channels matching the given {@code pattern} and emit {@link Message messages} received for
+	 * those. The {@link Mono} completes once the {@link Topic topic} subscriptions are registered.
+	 *
+	 * @param patterns must not be {@literal null}.
+	 * @return a hot sequence of {@link Message messages}.
+	 * @since 2.6
+	 * @see org.springframework.data.redis.listener.ReactiveRedisMessageListenerContainer#receiveLater(PatternTopic...)
+	 */
+	default Mono<Flux<? extends Message<String, V>>> listenToPatternLater(String... patterns) {
+
+		Assert.notNull(patterns, "Patterns must not be null!");
+		return listenToLater(Arrays.stream(patterns).map(PatternTopic::of).toArray(PatternTopic[]::new));
+	}
+
+	/**
+	 * Subscribe to the Redis channels for the given {@link Topic topics} and emit {@link Message messages} received for
+	 * those. The {@link Mono} completes once the {@link Topic topic} subscriptions are registered.
+	 *
+	 * @param topics must not be {@literal null}.
+	 * @return a hot sequence of {@link Message messages}.
+	 * @since 2.6
+	 * @see org.springframework.data.redis.listener.ReactiveRedisMessageListenerContainer#receiveLater(Iterable,
+	 *      RedisSerializationContext.SerializationPair, RedisSerializationContext.SerializationPair)
+	 */
+	Mono<Flux<? extends Message<String, V>>> listenToLater(Topic... topics);
+
 	// -------------------------------------------------------------------------
 	// Methods dealing with Redis Keys
 	// -------------------------------------------------------------------------

src/main/java/org/springframework/data/redis/core/ReactiveRedisTemplate.java

@@ -237,6 +237,21 @@ public Flux<? extends Message<String, V>> listenTo(Topic... topics) {
 				.doFinally((signalType) -> container.destroyLater().subscribe());
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.core.ReactiveRedisOperations#listenToLater(org.springframework.data.redis.listener.Topic[])
+	 */
+	@Override
+	@SuppressWarnings({ "unchecked", "rawtypes" })
+	public Mono<Flux<? extends Message<String, V>>> listenToLater(Topic... topics) {
+
+		ReactiveRedisMessageListenerContainer container = new ReactiveRedisMessageListenerContainer(getConnectionFactory());
+
+		return (Mono) container.receiveLater(Arrays.asList(topics), getSerializationContext().getStringSerializationPair(),
+						getSerializationContext().getValueSerializationPair()) //
+				.doFinally((signalType) -> container.destroyLater().subscribe());
+	}
+
 	// -------------------------------------------------------------------------
 	// Methods dealing with Redis keys
 	// -------------------------------------------------------------------------

src/main/java/org/springframework/data/redis/listener/ReactiveRedisMessageListenerContainer.java

@@ -343,7 +343,7 @@ private <C, B> Flux<Message<C, B>> doReceive(SerializationPair<C> channelSeriali
 	 * @throws InvalidDataAccessApiUsageException if {@code topics} is empty.
 	 * @since 2.6
 	 */
-	private <C, B> Mono<Flux<Message<C, B>>> receiveLater(Iterable<? extends Topic> topics,
+	public <C, B> Mono<Flux<Message<C, B>>> receiveLater(Iterable<? extends Topic> topics,
 			SerializationPair<C> channelSerializer, SerializationPair<B> messageSerializer) {
 
 		Assert.notNull(topics, "Topics must not be null!");

src/test/java/org/springframework/data/redis/core/ReactiveRedisTemplateIntegrationTests.java

@@ -19,6 +19,7 @@
 import static org.assertj.core.api.Assumptions.*;
 
 import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
 import java.time.Duration;
@@ -27,6 +28,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.function.Function;
 
 import org.junit.jupiter.api.BeforeEach;
 
@@ -441,7 +443,29 @@ void listenToChannelShouldReceiveChannelMessagesCorrectly() throws InterruptedEx
 
 		redisTemplate.listenToChannel(channel).as(StepVerifier::create) //
 				.thenAwait(Duration.ofMillis(500)) // just make sure we the subscription completed
-				.then(() -> redisTemplate.convertAndSend(channel, message).block()) //
+				.then(() -> redisTemplate.convertAndSend(channel, message).subscribe()) //
+				.assertNext(received -> {
+
+					assertThat(received).isInstanceOf(ChannelMessage.class);
+					assertThat(received.getMessage()).isEqualTo(message);
+					assertThat(received.getChannel()).isEqualTo(channel);
+				}) //
+				.thenAwait(Duration.ofMillis(10)) //
+				.thenCancel() //
+				.verify(Duration.ofSeconds(3));
+	}
+
+	@ParameterizedRedisTest // GH-1622
+	@EnabledIfLongRunningTest
+	void listenToLaterChannelShouldReceiveChannelMessagesCorrectly() {
+
+		String channel = "my-channel";
+
+		V message = valueFactory.instance();
+
+		redisTemplate.listenToChannelLater(channel) //
+				.doOnNext(it -> redisTemplate.convertAndSend(channel, message).subscribe()).flatMapMany(Function.identity()) //
+				.as(StepVerifier::create) //
 				.assertNext(received -> {
 
 					assertThat(received).isInstanceOf(ChannelMessage.class);
@@ -455,7 +479,7 @@ void listenToChannelShouldReceiveChannelMessagesCorrectly() throws InterruptedEx
 
 	@ParameterizedRedisTest // DATAREDIS-612
 	@EnabledIfLongRunningTest
-	void listenToChannelPatternShouldReceiveChannelMessagesCorrectly() throws InterruptedException {
+	void listenToPatternShouldReceiveChannelMessagesCorrectly() {
 
 		String channel = "my-channel";
 		String pattern = "my-*";
@@ -466,7 +490,32 @@ void listenToChannelPatternShouldReceiveChannelMessagesCorrectly() throws Interr
 
 		stream.as(StepVerifier::create) //
 				.thenAwait(Duration.ofMillis(500)) // just make sure we the subscription completed
-				.then(() -> redisTemplate.convertAndSend(channel, message).block()) //
+				.then(() -> redisTemplate.convertAndSend(channel, message).subscribe()) //
+				.assertNext(received -> {
+
+					assertThat(received).isInstanceOf(PatternMessage.class);
+					assertThat(received.getMessage()).isEqualTo(message);
+					assertThat(received.getChannel()).isEqualTo(channel);
+					assertThat(((PatternMessage) received).getPattern()).isEqualTo(pattern);
+				}) //
+				.thenCancel() //
+				.verify(Duration.ofSeconds(3));
+	}
+
+	@ParameterizedRedisTest // GH-1622
+	@EnabledIfLongRunningTest
+	void listenToPatternLaterShouldReceiveChannelMessagesCorrectly() {
+
+		String channel = "my-channel";
+		String pattern = "my-*";
+
+		V message = valueFactory.instance();
+
+		Mono<Flux<? extends Message<String, V>>> stream = redisTemplate.listenToPatternLater(pattern);
+
+		stream.doOnNext(it -> redisTemplate.convertAndSend(channel, message).subscribe()) //
+				.flatMapMany(Function.identity()) //
+				.as(StepVerifier::create) //
 				.assertNext(received -> {
 
 					assertThat(received).isInstanceOf(PatternMessage.class);