chore(kafka): Implement kafka binding with support for Domain Events

.gitignore

@@ -644,4 +644,5 @@ MigrationBackup/
 # End of https://www.toptal.com/developers/gitignore/api/macos,linux,windows,gradle,java,intellij,visualstudio,eclipse
 contiperf-report
 
-samples/async/local-example/
+samples/async/local-example/
+.kafka-env

async/async-commons-api/src/test/java/org/reactivecommons/async/api/HandlerRegistryTest.java

@@ -5,7 +5,12 @@
 import org.junit.jupiter.api.Test;
 import org.reactivecommons.api.domain.Command;
 import org.reactivecommons.api.domain.DomainEvent;
-import org.reactivecommons.async.api.handlers.*;
+import org.reactivecommons.async.api.handlers.CloudCommandHandler;
+import org.reactivecommons.async.api.handlers.CloudEventHandler;
+import org.reactivecommons.async.api.handlers.DomainCommandHandler;
+import org.reactivecommons.async.api.handlers.DomainEventHandler;
+import org.reactivecommons.async.api.handlers.QueryHandler;
+import org.reactivecommons.async.api.handlers.QueryHandlerDelegate;
 import org.reactivecommons.async.api.handlers.registered.RegisteredCommandHandler;
 import org.reactivecommons.async.api.handlers.registered.RegisteredEventListener;
 import org.reactivecommons.async.api.handlers.registered.RegisteredQueryHandler;
@@ -152,7 +157,7 @@ void handleDomainCommand() {
 
     @Test
     void handleCloudEventCommand() {
-        SomeCloudEventCommandHandler cloudCommandHandler = new SomeCloudEventCommandHandler();
+        SomeCloudCommandHandler cloudCommandHandler = new SomeCloudCommandHandler();
 
         registry.handleCloudEventCommand(name, cloudCommandHandler);
 
@@ -197,7 +202,7 @@ void serveQueryWithLambda() {
     @Test
     void serveQueryWithTypeInference() {
         QueryHandler<SomeDataClass, SomeDataClass> handler = new SomeQueryHandler();
-        registry.serveQuery(name, handler,SomeDataClass.class);
+        registry.serveQuery(name, handler, SomeDataClass.class);
         assertThat(registry.getHandlers()).anySatisfy(registered -> {
             assertThat(registered).extracting(RegisteredQueryHandler::getPath, RegisteredQueryHandler::getQueryClass)
                     .containsExactly(name, SomeDataClass.class);
@@ -252,7 +257,7 @@ public Mono<Void> handle(Command<SomeDataClass> message) {
         }
     }
 
-    private static class SomeCloudEventCommandHandler implements CloudCommandHandler {
+    private static class SomeCloudCommandHandler implements CloudCommandHandler {
         @Override
         public Mono<Void> handle(CloudEvent message) {
             return null;

async/async-kafka/async-kafka.gradle

@@ -0,0 +1,12 @@
+ext {
+    artifactId = 'async-kafka'
+    artifactDescription = 'Async Kafka'
+}
+
+dependencies {
+    api project(':async-commons-api')
+    api project(':domain-events-api')
+    api project(':async-commons')
+    api 'io.projectreactor.kafka:reactor-kafka:1.3.23'
+    api 'io.cloudevents:cloudevents-json-jackson:4.0.1'
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/KafkaDomainEventBus.java

@@ -0,0 +1,23 @@
+package org.reactivecommons.async.kafka;
+
+import io.cloudevents.CloudEvent;
+import lombok.AllArgsConstructor;
+import org.reactivecommons.api.domain.DomainEvent;
+import org.reactivecommons.api.domain.DomainEventBus;
+import org.reactivecommons.async.kafka.communications.ReactiveMessageSender;
+import org.reactivestreams.Publisher;
+
+@AllArgsConstructor
+public class KafkaDomainEventBus implements DomainEventBus {
+    private final ReactiveMessageSender sender;
+
+    @Override
+    public <T> Publisher<Void> emit(DomainEvent<T> event) {
+        return sender.send(event);
+    }
+
+    @Override
+    public Publisher<Void> emit(CloudEvent event) {
+        return sender.send(event);
+    }
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/KafkaMessage.java

@@ -0,0 +1,52 @@
+package org.reactivecommons.async.kafka;
+
+import lombok.Data;
+import org.apache.kafka.common.header.Headers;
+import org.reactivecommons.async.commons.communications.Message;
+import reactor.kafka.receiver.ReceiverRecord;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.reactivecommons.async.kafka.converters.json.KafkaJacksonMessageConverter.CONTENT_TYPE;
+
+
+@Data
+public class KafkaMessage implements Message {
+    private final byte[] body;
+    private final Properties properties;
+
+    @Data
+    public static class KafkaMessageProperties implements Properties {
+        private long contentLength;
+        private String key;
+        private String topic;
+        private Map<String, Object> headers = new HashMap<>();
+
+        @Override
+        public String getContentType() {
+            return (String) headers.get(CONTENT_TYPE);
+        }
+    }
+
+    public static KafkaMessage fromDelivery(ReceiverRecord<String, byte[]> record) {
+        return new KafkaMessage(record.value(), createMessageProps(record));
+    }
+
+    private static Properties createMessageProps(ReceiverRecord<String, byte[]> record) {
+        Map<String, Object> headers = parseHeaders(record.headers());
+
+        final KafkaMessageProperties properties = new KafkaMessageProperties();
+        properties.setHeaders(headers);
+        properties.setKey(record.key());
+        properties.setTopic(record.topic());
+        properties.setContentLength(record.value().length);
+        return properties;
+    }
+
+    private static Map<String, Object> parseHeaders(Headers headers) {
+        Map<String, Object> parsedHeaders = new HashMap<>();
+        headers.forEach(header -> parsedHeaders.put(header.key(), new String(header.value())));
+        return parsedHeaders;
+    }
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/communications/ReactiveMessageListener.java

@@ -0,0 +1,30 @@
+package org.reactivecommons.async.kafka.communications;
+
+import lombok.AllArgsConstructor;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import reactor.core.publisher.Flux;
+import reactor.kafka.receiver.KafkaReceiver;
+import reactor.kafka.receiver.ReceiverOptions;
+import reactor.kafka.receiver.ReceiverRecord;
+
+import java.util.List;
+
+
+@AllArgsConstructor
+public class ReactiveMessageListener {
+    private final ReceiverOptions<String, byte[]> receiverOptions;
+
+    public Flux<ReceiverRecord<String, byte[]>> listen(String groupId, List<String> topics) { // Notification events
+        ReceiverOptions<String, byte[]> options = receiverOptions.consumerProperty(ConsumerConfig.GROUP_ID_CONFIG, groupId);
+        return KafkaReceiver.create(options.subscription(topics))
+                .receive();
+    }
+
+    public int getMaxConcurrency() {
+        Object property = receiverOptions.consumerProperty(ConsumerConfig.MAX_POLL_RECORDS_CONFIG);
+        if (property instanceof Integer) {
+            return (int) property;
+        }
+        return ConsumerConfig.DEFAULT_MAX_POLL_RECORDS;
+    }
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/communications/ReactiveMessageSender.java

@@ -0,0 +1,91 @@
+package org.reactivecommons.async.kafka.communications;
+
+import lombok.SneakyThrows;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.header.Header;
+import org.apache.kafka.common.header.internals.RecordHeader;
+import org.reactivecommons.async.commons.converters.MessageConverter;
+import org.reactivecommons.async.kafka.KafkaMessage;
+import org.reactivecommons.async.kafka.communications.topology.TopologyCreator;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.FluxSink;
+import reactor.core.publisher.Mono;
+import reactor.core.publisher.MonoSink;
+import reactor.kafka.sender.KafkaSender;
+import reactor.kafka.sender.SenderRecord;
+import reactor.kafka.sender.SenderResult;
+
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
+
+public class ReactiveMessageSender {
+    private final ConcurrentHashMap<String, MonoSink<Void>> confirmations = new ConcurrentHashMap<>();
+    private final CopyOnWriteArrayList<FluxSink<SenderRecord<String, byte[], String>>> fluxSinks = new CopyOnWriteArrayList<>();
+    private final AtomicLong counter = new AtomicLong();
+
+    private final ExecutorService executorServiceConfirm = Executors.newFixedThreadPool(13, r -> new Thread(r, "KMessageSender1-" + counter.getAndIncrement()));
+    private final ExecutorService executorServiceEmit = Executors.newFixedThreadPool(13, r -> new Thread(r, "KMessageSender2-" + counter.getAndIncrement()));
+
+    private final int senderCount = 4;
+
+    private final MessageConverter messageConverter;
+    private final TopologyCreator topologyCreator;
+
+    public ReactiveMessageSender(KafkaSender<String, byte[]> sender, MessageConverter messageConverter,
+                                 TopologyCreator topologyCreator) {
+        this.messageConverter = messageConverter;
+        this.topologyCreator = topologyCreator;
+        for (int i = 0; i < senderCount; ++i) {
+            Flux<SenderRecord<String, byte[], String>> source = Flux.create(fluxSinks::add);
+            sender.send(source)
+                    .doOnNext(this::confirm)
+                    .subscribe();
+        }
+    }
+
+    public <V> Mono<Void> send(V message) {
+        return Mono.create(sink -> {
+            SenderRecord<String, byte[], String> record = createRecord(message);
+            confirmations.put(record.key(), sink);
+            executorServiceEmit.submit(() -> fluxSinks.get((int) (System.currentTimeMillis() % senderCount)).next(record));
+        });
+    }
+
+    private void confirm(SenderResult<String> result) {
+        executorServiceConfirm.submit(() -> {
+            MonoSink<Void> sink = confirmations.remove(result.correlationMetadata());
+            if (sink != null) {
+                if (result.exception() != null) {
+                    sink.error(result.exception());
+                } else {
+                    sink.success();
+                }
+            }
+        });
+    }
+
+    private <V> SenderRecord<String, byte[], String> createRecord(V object) {
+        KafkaMessage message = (KafkaMessage) messageConverter.toMessage(object);
+        ProducerRecord<String, byte[]> record = createProducerRecord(message);
+        return SenderRecord.create(record, message.getProperties().getKey()); // TODO: Review for Request-Reply
+    }
+
+    @SneakyThrows
+    private ProducerRecord<String, byte[]> createProducerRecord(KafkaMessage message) {
+        topologyCreator.checkTopic(message.getProperties().getTopic());
+
+        List<Header> headers = message.getProperties().getHeaders().entrySet().stream()
+                .map(entry -> new RecordHeader(entry.getKey(), entry.getValue()
+                        .toString().getBytes(StandardCharsets.UTF_8)))
+                .collect(Collectors.toList());
+
+        return new ProducerRecord<>(message.getProperties().getTopic(), null,
+                message.getProperties().getKey(), message.getBody(), headers);
+    }
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/communications/exceptions/TopicNotFoundException.java

@@ -0,0 +1,7 @@
+package org.reactivecommons.async.kafka.communications.exceptions;
+
+public class TopicNotFoundException extends RuntimeException {
+    public TopicNotFoundException(String message) {
+        super(message);
+    }
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/communications/topology/KafkaCustomizations.java

@@ -0,0 +1,26 @@
+package org.reactivecommons.async.kafka.communications.topology;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class KafkaCustomizations {
+    private Map<String, TopicCustomization> topics = new HashMap<>();
+
+    public static KafkaCustomizations withTopic(String topic, TopicCustomization customization) {
+        KafkaCustomizations customizations = new KafkaCustomizations();
+        customizations.getTopics().put(topic, customization);
+        return customizations;
+    }
+
+    public KafkaCustomizations addTopic(String topic, TopicCustomization customization) {
+        this.getTopics().put(topic, customization);
+        return this;
+    }
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/communications/topology/TopicCustomization.java

@@ -0,0 +1,19 @@
+package org.reactivecommons.async.kafka.communications.topology;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.util.Map;
+
+@Data
+@Builder
+@AllArgsConstructor
+@NoArgsConstructor
+public class TopicCustomization {
+    private String topic;
+    private int partitions;
+    private short replicationFactor;
+    private Map<String, String> config;
+}

async/async-kafka/src/main/java/org/reactivecommons/async/kafka/communications/topology/TopologyCreator.java

@@ -0,0 +1,76 @@
+package org.reactivecommons.async.kafka.communications.topology;
+
+import lombok.SneakyThrows;
+import org.apache.kafka.clients.admin.AdminClient;
+import org.apache.kafka.clients.admin.ListTopicsOptions;
+import org.apache.kafka.clients.admin.ListTopicsResult;
+import org.apache.kafka.clients.admin.NewTopic;
+import org.apache.kafka.common.errors.TopicExistsException;
+import org.reactivecommons.async.kafka.communications.exceptions.TopicNotFoundException;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class TopologyCreator {
+    public static final int TIMEOUT_MS = 60_000;
+    private final AdminClient adminClient;
+    private final KafkaCustomizations customizations;
+    private final Map<String, Boolean> existingTopics;
+
+    public TopologyCreator(AdminClient adminClient, KafkaCustomizations customizations) {
+        this.adminClient = adminClient;
+        this.customizations = customizations;
+        this.existingTopics = getTopics();
+    }
+
+    @SneakyThrows
+    public Map<String, Boolean> getTopics() {
+        ListTopicsResult topics = adminClient.listTopics(new ListTopicsOptions().timeoutMs(TIMEOUT_MS));
+        return topics.names().get().stream().collect(Collectors.toConcurrentMap(name -> name, name -> true));
+    }
+
+    public Mono<Void> createTopics(List<String> topics) {
+        TopicCustomization.TopicCustomizationBuilder defaultBuilder = TopicCustomization.builder()
+                .partitions(-1)
+                .replicationFactor((short) -1);
+
+        return Flux.fromIterable(topics)
+                .map(topic -> {
+                    if (customizations.getTopics().containsKey(topic)) {
+                        return customizations.getTopics().get(topic);
+                    }
+                    return defaultBuilder.topic(topic).build();
+                })
+                .map(this::toNewTopic)
+                .flatMap(this::createTopic)
+                .doOnNext(topic -> existingTopics.put(topic.name(), true))
+                .then();
+    }
+
+    protected Mono<NewTopic> createTopic(NewTopic topic) {
+        return Mono.fromFuture(adminClient.createTopics(List.of(topic))
+                        .all()
+                        .toCompletionStage()
+                        .toCompletableFuture())
+                .thenReturn(topic)
+                .onErrorResume(TopicExistsException.class, e -> Mono.just(topic));
+    }
+
+    protected NewTopic toNewTopic(TopicCustomization customization) {
+        NewTopic topic = new NewTopic(customization.getTopic(), customization.getPartitions(), customization.getReplicationFactor());
+        if (customization.getConfig() != null) {
+            return topic.configs(customization.getConfig());
+        }
+        return topic;
+    }
+
+    public void checkTopic(String topicName) {
+        if (!existingTopics.containsKey(topicName)) {
+            throw new TopicNotFoundException("Topic not found: " + topicName + ". Please create it before send a message.");
+            // TODO: should refresh topics?? getTopics();
+        }
+    }
+}