Add guide applications for spring-boot-eventeria (#29)

- add spring-boot-eventeria application in guide-projects directory
- introduce FunctionalBindingSupports

guide-projects/spring-boot-eventeria-guide/build.gradle

@@ -0,0 +1,18 @@
+plugins {
+    id "eventeria.java-conventions"
+    id "eventeria.verification-conventions"
+    id "eventeria.spring-dependency-management-conventions"
+}
+
+dependencies {
+    implementation project(":spring-boot-eventeria")
+    implementation("org.springframework.boot:spring-boot-starter-web")
+
+    compileOnly("org.projectlombok:lombok")
+    annotationProcessor("org.projectlombok:lombok")
+
+    // for embedded kafka
+    implementation("org.springframework.kafka:spring-kafka-test")
+
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
+}

guide-projects/spring-boot-eventeria-guide/lombok.config

@@ -0,0 +1,3 @@
+lombok.anyConstructor.addConstructorProperties=true
+lombok.copyableAnnotations += org.springframework.beans.factory.annotation.Qualifier
+lombok.copyableAnnotations += org.springframework.beans.factory.annotation.Value

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/SpringBootEventeriaGuideApplication.java

@@ -0,0 +1,11 @@
+package com.navercorp.eventeria.guide.boot;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SpringBootEventeriaGuideApplication {
+	public static void main(String[] args) {
+		SpringApplication.run(SpringBootEventeriaGuideApplication.class, args);
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/config/EmbeddedKafkaHolder.java

@@ -0,0 +1,45 @@
+package com.navercorp.eventeria.guide.boot.config;
+
+import java.util.List;
+
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.kafka.KafkaException;
+import org.springframework.kafka.test.EmbeddedKafkaBroker;
+import org.springframework.kafka.test.EmbeddedKafkaZKBroker;
+
+public final class EmbeddedKafkaHolder implements InitializingBean {
+
+	private static final EmbeddedKafkaBroker embeddedKafka = new EmbeddedKafkaZKBroker(1, false)
+		.brokerListProperty("spring.kafka.bootstrap-servers");
+
+	private static boolean started;
+
+	private final List<String> topics;
+
+	EmbeddedKafkaHolder(List<String> topics) {
+		super();
+		this.topics = topics;
+	}
+
+	public static EmbeddedKafkaBroker getEmbeddedKafka() {
+		if (!started) {
+			try {
+				embeddedKafka.afterPropertiesSet();
+			} catch (Exception e) {
+				throw new KafkaException("Embedded broker failed to start", e);
+			}
+			started = true;
+		}
+		return embeddedKafka;
+	}
+
+	@Override
+	public void afterPropertiesSet() {
+		embeddedKafka.afterPropertiesSet();
+		started = true;
+
+		embeddedKafka.addTopics(
+			topics.toArray(String[]::new)
+		);
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/config/KafkaConfig.java

@@ -0,0 +1,27 @@
+package com.navercorp.eventeria.guide.boot.config;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class KafkaConfig {
+
+	@Bean("topicsMap")
+	@ConfigurationProperties(prefix = "topics")
+	Map<String, String> topicsMap() {
+		return new HashMap<>();
+	}
+
+	@Bean
+	EmbeddedKafkaHolder embeddedKafkaHolder(
+		@Qualifier("topicsMap") Map<String, String> topicsMap
+	) {
+		return new EmbeddedKafkaHolder(List.copyOf(topicsMap.values()));
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/config/MessageConfig.java

@@ -0,0 +1,93 @@
+package com.navercorp.eventeria.guide.boot.config;
+
+import java.util.function.Function;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.cloud.stream.binding.SubscribableChannelBindingTargetFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import io.cloudevents.core.provider.EventFormatProvider;
+import io.cloudevents.jackson.JsonFormat;
+import lombok.RequiredArgsConstructor;
+
+import com.navercorp.eventeria.guide.boot.domain.AfterPostCreationCommand.NotifyToSubscribers;
+import com.navercorp.eventeria.guide.boot.domain.PostCreatedEvent;
+import com.navercorp.eventeria.messaging.contract.Message;
+import com.navercorp.eventeria.messaging.contract.cloudevents.serializer.CloudEventMessageReaderWriter;
+import com.navercorp.eventeria.messaging.contract.serializer.MessageSerializerDeserializer;
+import com.navercorp.eventeria.messaging.jackson.serializer.JacksonMessageSerializer;
+import com.navercorp.eventeria.messaging.spring.cloud.stream.binding.ChannelBindable;
+import com.navercorp.eventeria.messaging.spring.cloud.stream.binding.ChannelBinder;
+import com.navercorp.eventeria.messaging.spring.cloud.stream.binding.DefaultChannelBinder;
+import com.navercorp.eventeria.messaging.typealias.CloudEventMessageTypeAliasMapper;
+import com.navercorp.spring.boot.eventeria.support.FunctionalBindingSupports;
+
+@Configuration
+@RequiredArgsConstructor
+public class MessageConfig {
+
+	private final ObjectMapper objectMapper;
+
+	static {
+		EventFormatProvider.getInstance()
+			.registerFormat(
+				new JsonFormat()
+					.withForceExtensionNameLowerCaseDeserialization()
+					.withForceIgnoreInvalidExtensionNameDeserialization()
+			);
+	}
+
+	@Bean
+	MessageSerializerDeserializer messageSerializerDeserializer() {
+		return new JacksonMessageSerializer(objectMapper);
+	}
+
+	@Bean
+	CloudEventMessageTypeAliasMapper cloudEventMessageTypeAliasMapper() {
+		CloudEventMessageTypeAliasMapper typeAliasMapper = new CloudEventMessageTypeAliasMapper();
+
+		typeAliasMapper.addCompatibleTypeAlias(
+			PostCreatedEvent.class,
+			"com.navercorp.eventeria.guide.boot.domain.PostCreatedEvent"
+		);
+
+		typeAliasMapper.addCompatibleTypeAlias(
+			NotifyToSubscribers.class,
+			"com.navercorp.eventeria.guide.boot.domain.AfterPostCreationCommand$NotifyToSubscribers"
+		);
+
+		return typeAliasMapper;
+	}
+
+	@Bean
+	ChannelBindable channelBindable() {
+		return new ChannelBindable();
+	}
+
+	@Bean
+	@ConditionalOnMissingBean
+	ChannelBinder channelBinder(
+		SubscribableChannelBindingTargetFactory bindingTargetFactory,
+		ChannelBindable channelBindable
+	) {
+		return new DefaultChannelBinder(bindingTargetFactory, channelBindable);
+	}
+
+	/**
+	 * Consume and converts messages from messaging system to {@link Message}
+	 *
+	 * @param cloudEventMessageReaderWriter
+	 * @see #cloudEventMessageTypeAliasMapper()
+	 * @see spring.cloud.function.definition application.yml
+	 * @return type of {@link Message}
+	 */
+	@Bean
+	Function<org.springframework.messaging.Message<byte[]>, Message> transformCloudEventToMessage(
+		CloudEventMessageReaderWriter cloudEventMessageReaderWriter
+	) {
+		return FunctionalBindingSupports.convertToMessage(cloudEventMessageReaderWriter);
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/controller/PostApiController.java

@@ -0,0 +1,64 @@
+package com.navercorp.eventeria.guide.boot.controller;
+
+import java.time.Instant;
+
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+import lombok.Builder;
+import lombok.RequiredArgsConstructor;
+
+import com.navercorp.eventeria.guide.boot.domain.CreatePostService;
+import com.navercorp.eventeria.guide.boot.domain.Post;
+
+@RestController
+@RequiredArgsConstructor
+public class PostApiController {
+
+	private final CreatePostService createPostService;
+
+	@PostMapping("/posts/{postId}")
+	public PostResponse createPost(
+		@PathVariable long postId,
+		@RequestBody CreatePostRequest request
+	) {
+		Post post = createPostService.create(
+			Post.builder()
+				.id(postId)
+				.writerId(request.writerId())
+				.content(request.content())
+				.createdAt(Instant.now())
+				.build()
+		);
+
+		return PostResponse.builder()
+			.id(post.id())
+			.writerId(post.writerId())
+			.content(post.content())
+			.createdAt(post.createdAt())
+			.build();
+	}
+
+	public record CreatePostRequest(
+		long id,
+
+		String writerId,
+
+		String content
+	) {
+	}
+
+	@Builder
+	public record PostResponse(
+		long id,
+
+		String writerId,
+
+		String content,
+
+		Instant createdAt
+	) {
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/domain/AfterPostCommandHandler.java

@@ -0,0 +1,28 @@
+package com.navercorp.eventeria.guide.boot.domain;
+
+import org.springframework.stereotype.Component;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+import com.navercorp.eventeria.guide.boot.domain.AfterPostCreationCommand.ApplySearchIndex;
+import com.navercorp.eventeria.guide.boot.domain.AfterPostCreationCommand.RefreshPostRanking;
+import com.navercorp.eventeria.guide.boot.domain.AfterPostCreationCommand.UpdateUserStatistic;
+
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class AfterPostCommandHandler {
+
+	public void updateUserStatistic(UpdateUserStatistic command) {
+		log.info("[CONSUME][UpdateUserStatistic] {}", command);
+	}
+
+	public void refreshPostRanking(RefreshPostRanking command) {
+		log.info("[CONSUME][RefreshPostRanking] {}", command);
+	}
+
+	public void applySearchIndex(ApplySearchIndex command) {
+		log.info("[CONSUME][ApplySearchIndex] {}", command);
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/domain/AfterPostCreationCommand.java

@@ -0,0 +1,44 @@
+package com.navercorp.eventeria.guide.boot.domain;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+import com.navercorp.eventeria.messaging.contract.command.AbstractCommand;
+import com.navercorp.eventeria.messaging.contract.command.Command;
+
+public sealed interface AfterPostCreationCommand extends Command {
+
+	@Override
+	default String getSourceType() {
+		return Post.class.getName();
+	}
+
+	// functional binding, concurrent
+	@Getter
+	@RequiredArgsConstructor
+	final class NotifyToSubscribers extends AbstractCommand implements AfterPostCreationCommand {
+		private final long postId;
+	}
+
+	// programmatic binding
+	@Getter
+	@RequiredArgsConstructor(staticName = "of")
+	final class UpdateUserStatistic extends AbstractCommand implements AfterPostCreationCommand {
+		private final long postId;
+		private final String writerId;
+	}
+
+	// programmatic binding
+	@Getter
+	@RequiredArgsConstructor(staticName = "from")
+	final class RefreshPostRanking extends AbstractCommand implements AfterPostCreationCommand {
+		private final long postId;
+	}
+
+	// programmatic binding
+	@Getter
+	@RequiredArgsConstructor(staticName = "from")
+	final class ApplySearchIndex extends AbstractCommand implements AfterPostCreationCommand {
+		private final long postId;
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/domain/CreatePostService.java

@@ -0,0 +1,31 @@
+package com.navercorp.eventeria.guide.boot.domain;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Service;
+
+import lombok.RequiredArgsConstructor;
+
+import com.navercorp.eventeria.guide.boot.publisher.ProgrammaticBindingEventPublisher;
+import com.navercorp.eventeria.messaging.spring.integration.channel.SpringMessagePublisher;
+
+@Service
+@RequiredArgsConstructor
+public class CreatePostService {
+
+	@Qualifier(ProgrammaticBindingEventPublisher.OUTBOUND_BEAN_NAME)
+	private final SpringMessagePublisher springMessagePublisher;
+
+	/**
+	 * publish {@link PostCreatedEvent} and return request parameter.
+	 *
+	 * @param post
+	 * @return
+	 */
+	public Post create(Post post) {
+		springMessagePublisher.publish(
+			PostCreatedEvent.from(post)
+		);
+
+		return post;
+	}
+}

guide-projects/spring-boot-eventeria-guide/src/main/java/com/navercorp/eventeria/guide/boot/domain/Post.java

@@ -0,0 +1,17 @@
+package com.navercorp.eventeria.guide.boot.domain;
+
+import java.time.Instant;
+
+import lombok.Builder;
+
+@Builder
+public record Post(
+	long id,
+
+	String writerId,
+
+	String content,
+
+	Instant createdAt
+) {
+}