Apache Kafka 参考指南

import io.smallrye.reactive.messaging.annotations.Blocking;
import org.eclipse.microprofile.reactive.messaging.Incoming;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.transaction.Transactional;

@ApplicationScoped
public class PriceStorage {

    @Incoming("prices")
    @Transactional
    public void store(int priceInUsd) {
        Price price = new Price();
        price.value = priceInUsd;
        price.persist();
    }

}

@Incoming("prices")
@Acknowledgment(Acknowledgment.Strategy.PRE_PROCESSING)
public void process(double price) {
    // process price
}

@Incoming("prices")
public CompletionStage<Void> process(Message<Double> msg) {
    // process price
    return msg.ack();
}

@Incoming("prices")
public void consume(List<Double> prices) {
    for (double price : prices) {
        // process price
    }
}

@Incoming("prices")
public CompletionStage<Void> consumeMessage(Message<ConsumerRecords<String, Double>> records) {
    for (ConsumerRecord<String, Double> record : records.getPayload()) {
        String payload = record.getPayload();
        String topic = record.getTopic();
        // process messages
    }
    // ack will commit the latest offsets (per partition) of the batch.
    return records.ack();
}

package org.acme;

import java.util.concurrent.CompletionStage;

import jakarta.enterprise.context.ApplicationScoped;

import org.eclipse.microprofile.reactive.messaging.Incoming;
import org.eclipse.microprofile.reactive.messaging.Message;

import io.smallrye.reactive.messaging.kafka.KafkaRecord;
import io.smallrye.reactive.messaging.kafka.commit.CheckpointMetadata;

@ApplicationScoped
public class MeanCheckpointConsumer {

    @Incoming("prices")
    public CompletionStage<Void> consume(Message<Double> record) {
        // Get the `CheckpointMetadata` from the incoming message
        CheckpointMetadata<AveragePrice> checkpoint = CheckpointMetadata.fromMessage(record);

        // `CheckpointMetadata` allows transforming the processing state
        // Applies the given function, starting from the value `0.0` when no previous state exists
        checkpoint.transform(new AveragePrice(), average -> average.update(record.getPayload()), /* persistOnAck */ true);

        // `persistOnAck` flag set to true, ack will persist the processing state
        // associated with the latest offset (per partition).
        return record.ack();
    }

    static class AveragePrice {
        long count;
        double mean;

        AveragePrice update(double newPrice) {
            mean += ((newPrice - mean) / ++count);
            return this;
        }
    }
}

import org.eclipse.microprofile.reactive.messaging.Channel;
import org.eclipse.microprofile.reactive.messaging.Emitter;

import jakarta.inject.Inject;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.core.MediaType;

@Path("/prices")
public class PriceResource {

    @Inject
    @Channel("price-create")
    Emitter<Double> priceEmitter;

    @POST
    @Consumes(MediaType.TEXT_PLAIN)
    public void addPrice(Double price) {
        CompletionStage<Void> ack = priceEmitter.send(price);
    }
}

import java.util.concurrent.CompletableFuture;
import org.eclipse.microprofile.reactive.messaging.Channel;
import org.eclipse.microprofile.reactive.messaging.Emitter;

import jakarta.inject.Inject;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.core.MediaType;

@Path("/prices")
public class PriceResource {

    @Inject @Channel("price-create") Emitter<Double> priceEmitter;

    @POST
    @Consumes(MediaType.TEXT_PLAIN)
    public void addPrice(Double price) {
        priceEmitter.send(Message.of(price)
            .withAck(() -> {
                // Called when the message is acked
                return CompletableFuture.completedFuture(null);
            })
            .withNack(throwable -> {
                // Called when the message is nacked
                return CompletableFuture.completedFuture(null);
            }));
    }
}

import org.eclipse.microprofile.reactive.messaging.Channel;

import jakarta.inject.Inject;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.core.MediaType;

import io.smallrye.reactive.messaging.MutinyEmitter;

@Path("/prices")
public class PriceResource {

    @Inject
    @Channel("price-create")
    MutinyEmitter<Double> priceEmitter;

    @POST
    @Consumes(MediaType.TEXT_PLAIN)
    public Uni<String> addPrice(Double price) {
        return quoteRequestEmitter.send(price)
                .map(x -> "ok")
                .onFailure().recoverWithItem("ko");
    }
}

@ApplicationScoped
@Identifier("failure-fallback") // Set the name of the failure handler
public class MySerializationFailureHandler
    implements SerializationFailureHandler<JsonObject> { // Specify the expected type

    @Override
    public byte[] decorateSerialization(Uni<byte[]> serialization, String topic, boolean isKey,
        String serializer, Object data, Headers headers) {
        return serialization
                    .onFailure().retry().atMost(3)
                    .await().indefinitely();
    }
}

import java.util.Random;

import jakarta.enterprise.context.ApplicationScoped;

import org.eclipse.microprofile.reactive.messaging.Incoming;
import org.eclipse.microprofile.reactive.messaging.Outgoing;

import io.smallrye.reactive.messaging.annotations.Broadcast;

@ApplicationScoped
public class MultipleConsumer {

    private final Random random = new Random();

    @Outgoing("in-memory-channel")
    @Broadcast
    double generate() {
        return random.nextDouble();
    }

    @Incoming("in-memory-channel")
    void consumeAndLog(double price) {
        System.out.println(price);
    }

    @Incoming("in-memory-channel")
    @Outgoing("prices2")
    double consumeAndSend(double price) {
        return price;
    }
}

import java.util.Random;

import jakarta.enterprise.context.ApplicationScoped;

import org.eclipse.microprofile.reactive.messaging.Outgoing;

@ApplicationScoped
public class MultipleProducers {

    private final Random random = new Random();

    @Outgoing("generated")
    @Outgoing("generated-2")
    double priceBroadcast() {
        return random.nextDouble();
    }

}

import jakarta.enterprise.context.ApplicationScoped;

import org.eclipse.microprofile.reactive.messaging.Incoming;
import org.eclipse.microprofile.reactive.messaging.Outgoing;

import io.smallrye.reactive.messaging.Targeted;

@ApplicationScoped
public class TargetedProducers {

    @Incoming("in")
    @Outgoing("out1")
    @Outgoing("out2")
    @Outgoing("out3")
    public Targeted process(double price) {
        Targeted targeted = Targeted.of("out1", "Price: " + price,
                "out2", "Quote: " + price);
        if (price > 90.0) {
            return targeted.with("out3", price);
        }
        return targeted;
    }

}

import jakarta.enterprise.context.ApplicationScoped;

import org.eclipse.microprofile.reactive.messaging.Channel;

import io.smallrye.mutiny.Uni;
import io.smallrye.reactive.messaging.kafka.KafkaRecord;
import io.smallrye.reactive.messaging.kafka.transactions.KafkaTransactions;

@ApplicationScoped
public class KafkaTransactionalProducer {

    @Channel("tx-out-example")
    KafkaTransactions<String> txProducer;

    public Uni<Void> emitInTransaction() {
        return txProducer.withTransaction(emitter -> {
            emitter.send(KafkaRecord.of(1, "a"));
            emitter.send(KafkaRecord.of(2, "b"));
            emitter.send(KafkaRecord.of(3, "c"));
            return Uni.createFrom().voidItem();
        });
    }

}

import jakarta.enterprise.context.ApplicationScoped;

import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.eclipse.microprofile.reactive.messaging.Channel;
import org.eclipse.microprofile.reactive.messaging.Incoming;
import org.eclipse.microprofile.reactive.messaging.Message;
import org.eclipse.microprofile.reactive.messaging.OnOverflow;

import io.smallrye.mutiny.Uni;
import io.smallrye.reactive.messaging.kafka.KafkaRecord;
import io.smallrye.reactive.messaging.kafka.transactions.KafkaTransactions;

@ApplicationScoped
public class KafkaExactlyOnceProcessor {

    @Channel("prices-out")
    @OnOverflow(value = OnOverflow.Strategy.BUFFER, bufferSize = 500) (3)
    KafkaTransactions<Integer> txProducer;

    @Incoming("prices-in")
    public Uni<Void> emitInTransaction(Message<ConsumerRecords<String, Integer>> batch) { (1)
        return txProducer.withTransactionAndAck(batch, emitter -> { (2)
            for (ConsumerRecord<String, Integer> record : batch.getPayload()) {
                emitter.send(KafkaRecord.of(record.key(), record.value() + 1)); (3)
            }
            return Uni.createFrom().voidItem();
        });
    }

}

mp.messaging.incoming.prices-in.commit-strategy=ignore
mp.messaging.incoming.prices-in.failure-strategy=ignore

package com.acme.fruit.jackson;

import io.quarkus.kafka.client.serialization.ObjectMapperDeserializer;

public class FruitDeserializer extends ObjectMapperDeserializer<Fruit> {
    public FruitDeserializer() {
        super(Fruit.class);
    }
}

# Configure the Kafka source (we read from it)
mp.messaging.incoming.fruit-in.topic=fruit-in
mp.messaging.incoming.fruit-in.value.deserializer=com.acme.fruit.jackson.FruitDeserializer

# Configure the Kafka sink (we write to it)
mp.messaging.outgoing.fruit-out.topic=fruit-out
mp.messaging.outgoing.fruit-out.value.serializer=io.quarkus.kafka.client.serialization.ObjectMapperSerializer

package com.acme.fruit.jackson;

import java.util.List;
import com.fasterxml.jackson.core.type.TypeReference;
import io.quarkus.kafka.client.serialization.ObjectMapperDeserializer;

public class ListOfFruitDeserializer extends ObjectMapperDeserializer<List<Fruit>> {
    public ListOfFruitDeserializer() {
        super(new TypeReference<List<Fruit>>() {});
    }
}

package com.acme.fruit.jsonb;

import io.quarkus.kafka.client.serialization.JsonbDeserializer;

public class FruitDeserializer extends JsonbDeserializer<Fruit> {
    public FruitDeserializer() {
        super(Fruit.class);
    }
}

# Configure the Kafka source (we read from it)
mp.messaging.incoming.fruit-in.connector=smallrye-kafka
mp.messaging.incoming.fruit-in.topic=fruit-in
mp.messaging.incoming.fruit-in.value.deserializer=com.acme.fruit.jsonb.FruitDeserializer

# Configure the Kafka sink (we write to it)
mp.messaging.outgoing.fruit-out.connector=smallrye-kafka
mp.messaging.outgoing.fruit-out.topic=fruit-out
mp.messaging.outgoing.fruit-out.value.serializer=io.quarkus.kafka.client.serialization.JsonbSerializer

package com.acme.fruit.jsonb;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;
import io.quarkus.kafka.client.serialization.JsonbDeserializer;

public class ListOfFruitDeserializer extends JsonbDeserializer<List<Fruit>> {
    public ListOfFruitDeserializer() {
        super(new ArrayList<MyEntity>() {}.getClass().getGenericSuperclass());
    }
}

# Disable both liveness and readiness checks with `health-enabled=false`:

# Incoming channel (receiving records form Kafka)
mp.messaging.incoming.your-channel.health-enabled=false
# Outgoing channel (writing records to Kafka)
mp.messaging.outgoing.your-channel.health-enabled=false

# Disable only the readiness check with `health-readiness-enabled=false`:

mp.messaging.incoming.your-channel.health-readiness-enabled=false
mp.messaging.outgoing.your-channel.health-readiness-enabled=false

smallrye.messaging.observation.enabled=true

@ApplicationScoped
public class BeverageProcessor {

    @Incoming("orders")
    @Outgoing("beverages")
    Beverage process(Order order) {
        System.out.println("Order received " + order.getProduct());
        Beverage beverage = new Beverage();
        beverage.setBeverage(order.getProduct());
        beverage.setCustomer(order.getCustomer());
        beverage.setOrderId(order.getOrderId());
        beverage.setPreparationState("RECEIVED");
        return beverage;
    }

}

public class KafkaTestResourceLifecycleManager implements QuarkusTestResourceLifecycleManager {

    @Override
    public Map<String, String> start() {
        Map<String, String> env = new HashMap<>();
        Map<String, String> props1 = InMemoryConnector.switchIncomingChannelsToInMemory("orders");     (1)
        Map<String, String> props2 = InMemoryConnector.switchOutgoingChannelsToInMemory("beverages");  (2)
        env.putAll(props1);
        env.putAll(props2);
        return env;  (3)
    }

    @Override
    public void stop() {
        InMemoryConnector.clear();  (4)
    }
}

import static org.awaitility.Awaitility.await;

@QuarkusTest
@QuarkusTestResource(KafkaTestResourceLifecycleManager.class)
class BaristaTest {

    @Inject
    @Connector("smallrye-in-memory")
    InMemoryConnector connector; (1)

    @Test
    void testProcessOrder() {
        InMemorySource<Order> ordersIn = connector.source("orders");     (2)
        InMemorySink<Beverage> beveragesOut = connector.sink("beverages");  (3)

        Order order = new Order();
        order.setProduct("coffee");
        order.setName("Coffee lover");
        order.setOrderId("1234");

        ordersIn.send(order);  (4)

        await().<List<? extends Message<Beverage>>>until(beveragesOut::received, t -> t.size() == 1); (5)

        Beverage queuedBeverage = beveragesOut.received().get(0).getPayload();
        Assertions.assertEquals(Beverage.State.READY, queuedBeverage.getPreparationState());
        Assertions.assertEquals("coffee", queuedBeverage.getBeverage());
        Assertions.assertEquals("Coffee lover", queuedBeverage.getCustomer());
        Assertions.assertEquals("1234", queuedBeverage.getOrderId());
    }

}

@ApplicationScoped
public class BeverageProcessor {

    @Incoming("orders")
    CompletionStage<Void> process(KafkaRecordBatch<String, Order> orders) {
        System.out.println("Order received " + orders.getPayload().size());
        return orders.ack();
    }
}

import static org.awaitility.Awaitility.await;

@QuarkusTest
@QuarkusTestResource(KafkaTestResourceLifecycleManager.class)
class BaristaTest {

    @Inject
    @Connector("smallrye-in-memory")

    InMemoryConnector connector;

    @Test
    void testProcessOrder() {
        InMemorySource<IncomingKafkaRecordBatch<String, Order>> ordersIn = connector.source("orders");
        var committed = new AtomicBoolean(false);  (1)
        var commitHandler = new KafkaCommitHandler() {
            @Override
            public <K, V> Uni<Void> handle(IncomingKafkaRecord<K, V> record) {
                committed.set(true);  (2)
                return null;
            }
        };
        var failureHandler = new KafkaFailureHandler() {
            @Override
            public <K, V> Uni<Void> handle(IncomingKafkaRecord<K, V> record, Throwable reason, Metadata metadata) {
                return null;
            }
        };

        Order order = new Order();
        order.setProduct("coffee");
        order.setName("Coffee lover");
        order.setOrderId("1234");
        var record = new ConsumerRecord<>("topic", 0, 0, "key", order);
        var records = new ConsumerRecords<>(Map.of(new TopicPartition("topic", 1), List.of(record)));
        var batch = new IncomingKafkaRecordBatch<>(
            records, "kafka", 0, commitHandler, failureHandler, false, false);  (3)

        ordersIn.send(batch);

        await().until(committed::get);  (4)
    }
}

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-test-kafka-companion</artifactId>
    <scope>test</scope>
</dependency>

import static org.junit.jupiter.api.Assertions.assertEquals;

import java.util.UUID;

import org.apache.kafka.clients.producer.ProducerRecord;
import org.junit.jupiter.api.Test;

import io.quarkus.test.common.QuarkusTestResource;
import io.quarkus.test.junit.QuarkusTest;
import io.quarkus.test.kafka.InjectKafkaCompanion;
import io.quarkus.test.kafka.KafkaCompanionResource;
import io.smallrye.reactive.messaging.kafka.companion.ConsumerTask;
import io.smallrye.reactive.messaging.kafka.companion.KafkaCompanion;

@QuarkusTest
@QuarkusTestResource(KafkaCompanionResource.class)
public class OrderProcessorTest {

    @InjectKafkaCompanion (1)
    KafkaCompanion companion;

    @Test
    void testProcessor() {
        companion.produceStrings().usingGenerator(i -> new ProducerRecord<>("orders", UUID.randomUUID().toString())); (2)

        // Expect that the tested application processes orders from 'orders' topic and write to 'orders-processed' topic

        ConsumerTask<String, String> orders = companion.consumeStrings().fromTopics("orders-processed", 10); (3)
        orders.awaitCompletion(); (4)
        assertEquals(10, orders.count());
    }
}

quarkus.kafka.devservices.provider=kafka-native

quarkus.kafka.devservices.provider=strimzi

quarkus.kafka.devservices.image-name=quay.io/strimzi-test-container/test-container:0.106.0-kafka-3.7.0

quarkus.kafka.devservices.topic-partitions.test=3
quarkus.kafka.devservices.topic-partitions.messages=2

quarkus.kafka.devservices.redpanda.transaction-enabled=false

name: <application name>
services:
  kafka:
    image: apache/kafka-native:3.9.0
    restart: "no"
    ports:
      - '9092'
    labels:
      io.quarkus.devservices.compose.exposed_ports: /etc/kafka/docker/ports
    environment:
      KAFKA_NODE_ID: 1
      KAFKA_PROCESS_ROLES: broker,controller
      KAFKA_LISTENERS: PLAINTEXT://:9092,CONTROLLER://:9093
      KAFKA_CONTROLLER_LISTENER_NAMES: CONTROLLER
      KAFKA_CONTROLLER_QUORUM_VOTERS: 1@localhost:9093
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1
      KAFKA_GROUP_INITIAL_REBALANCE_DELAY_MS: 0
      KAFKA_NUM_PARTITIONS: 3
    command: "/kafka.sh"
    volumes:
      - './kafka.sh:/kafka.sh'

mp.messaging.incoming.your-channel-name.attribute=value

kafka.bootstrap.servers=...

mp.messaging.incoming.[channel].max.poll.records=1000

mp.messaging.outgoing.your-channel-name.attribute=value

kafka.bootstrap.servers=...

mp.messaging.incoming.[channel].max.block.ms=10000

mp.messaging.incoming.my-channel.connector=smallrye-kafka
mp.messaging.incoming.my-channel.kafka-configuration=my-configuration

@Produces
@ApplicationScoped
@Identifier("my-configuration")
Map<String, Object> outgoing() {
    return Map.ofEntries(
            Map.entry("value.serializer", ObjectMapperSerializer.class.getName())
    );
}

package org.acme;

import java.util.concurrent.CompletionStage;

import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

import org.eclipse.microprofile.reactive.messaging.Channel;
import org.eclipse.microprofile.reactive.messaging.Emitter;

@Path("/")
public class ResourceSendingToKafka {

    @Channel("kafka") Emitter<String> emitter;          (1)

    @POST
    @Produces(MediaType.TEXT_PLAIN)
    public CompletionStage<Void> send(String payload) { (2)
        return emitter.send(payload);                   (3)
    }
}

mp.messaging.outgoing.kafka.connector=smallrye-kafka
mp.messaging.outgoing.kafka.topic=my-topic

package org.acme;

import java.util.concurrent.CompletionStage;

import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

import org.eclipse.microprofile.reactive.messaging.Channel;
import org.eclipse.microprofile.reactive.messaging.Emitter;

import io.smallrye.reactive.messaging.kafka.Record;

@Path("/")
public class ResourceSendingToKafka {

    @Channel("kafka") Emitter<Record<String,String>> emitter;  (1)


    @POST
    @Produces(MediaType.TEXT_PLAIN)
    public CompletionStage<Void> send(String payload) {
        return emitter.send(Record.of("my-key", payload));    (2)
    }
}

package org.acme;

import jakarta.persistence.Entity;

import io.quarkus.hibernate.orm.panache.PanacheEntity;

@Entity
public class Fruit extends PanacheEntity {

    public String name;

}

package org.acme;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.transaction.Transactional;

import org.eclipse.microprofile.reactive.messaging.Incoming;

import io.smallrye.common.annotation.Blocking;

@ApplicationScoped
public class FruitConsumer {

    @Incoming("fruits")                                     (1)
    @Transactional                                          (2)
    public void persistFruits(Fruit fruit) {                (3)
        fruit.persist();                                    (4)
    }
}

package org.acme;

import io.quarkus.kafka.client.serialization.ObjectMapperDeserializer;

public class FruitDeserializer extends ObjectMapperDeserializer<Fruit> {
    public FruitDeserializer() {
        super(Fruit.class);
    }
}

mp.messaging.incoming.fruits.connector=smallrye-kafka
mp.messaging.incoming.fruits.value.deserializer=org.acme.FruitDeserializer

package org.acme;

import jakarta.persistence.Entity;

import io.quarkus.hibernate.reactive.panache.PanacheEntity;  (1)

@Entity
public class Fruit extends PanacheEntity {

    public String name;

}

package org.acme;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.enterprise.context.control.ActivateRequestContext;

import org.eclipse.microprofile.reactive.messaging.Incoming;

import io.quarkus.hibernate.reactive.panache.Panache;
import io.smallrye.mutiny.Uni;

@ApplicationScoped
public class FruitStore {

    @Inject
    Mutiny.Session session;                    (1)

    @Incoming("in")
    @ActivateRequestContext (2)
    public Uni<Void> consume(Fruit entity) {
        return session.withTransaction(t -> {  (3)
            return entity.persistAndFlush()    (4)
                    .replaceWithVoid();        (5)
        }).onTermination().call(() -> session.close()); (6)
    }

}

package org.acme;

import io.quarkus.kafka.client.serialization.ObjectMapperDeserializer;

public class FruitDeserializer extends ObjectMapperDeserializer<Fruit> {
    public FruitDeserializer() {
        super(Fruit.class);
    }
}

mp.messaging.incoming.fruits.connector=smallrye-kafka
mp.messaging.incoming.fruits.value.deserializer=org.acme.FruitDeserializer

package org.acme;

import java.util.concurrent.CompletionStage;

import jakarta.transaction.Transactional;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.reactive.messaging.Channel;
import io.smallrye.reactive.messaging.MutinyEmitter;

@Path("/")
public class ResourceSendingToKafka {

    @Channel("kafka") MutinyEmitter<Fruit> emitter;

    @POST
    @Path("/fruits")
    @Transactional                                               (1)
    public void storeAndSendToKafka(Fruit fruit) {               (2)
        fruit.persist();
        emitter.sendAndAwait(new FruitDto(fruit));               (3)
    }
}

package org.acme;

import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.reactive.messaging.Channel;

import io.quarkus.hibernate.reactive.panache.Panache;
import io.smallrye.mutiny.Uni;
import io.smallrye.reactive.messaging.MutinyEmitter;

@Path("/")
public class ReactiveGreetingResource {

    @Channel("kafka") MutinyEmitter<Fruit> emitter;     (1)

    @POST
    @Path("/fruits")
    public Uni<Void> sendToKafka(Fruit fruit) {         (2)
        return Panache.withTransaction(() ->            (3)
            fruit.<Fruit>persist()
        )
            .chain(f -> emitter.send(f));               (4)
    }
}

@Channel("fruits")
Multi<Fruit> fruits;

@GET
@Produces(MediaType.SERVER_SENT_EVENTS)
public Multi<Fruit> stream() {
    return fruits;
}

@Channel("fruits")
Multi<Fruit> fruits;

@Inject
ObjectMapper mapper;

@GET
@Produces(MediaType.SERVER_SENT_EVENTS)
public Multi<String> stream() {
    return Multi.createBy().merging()
            .streams(
                    fruits.map(this::toJson),
                    emitAPeriodicPing()
            );
}

Multi<String> emitAPeriodicPing() {
    return Multi.createFrom().ticks().every(Duration.ofSeconds(10))
            .onItem().transform(x -> "{}");
}

private String toJson(Fruit f) {
    try {
        return mapper.writeValueAsString(f);
    } catch (JsonProcessingException e) {
        throw new RuntimeException(e);
    }
}

package org.acme;

import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.MediaType;

import org.eclipse.microprofile.faulttolerance.Bulkhead;
import org.eclipse.microprofile.reactive.messaging.Channel;
import org.hibernate.reactive.mutiny.Mutiny;

import io.quarkus.hibernate.reactive.panache.Panache;
import io.smallrye.mutiny.Uni;
import io.smallrye.reactive.messaging.kafka.transactions.KafkaTransactions;

@Path("/")
public class FruitProducer {

    @Channel("kafka") KafkaTransactions<Fruit> kafkaTx; (1)

    @POST
    @Path("/fruits")
    @Consumes(MediaType.APPLICATION_JSON)
    @Bulkhead(1) (2)
    public Uni<Void> post(Fruit fruit) { (3)
        return kafkaTx.withTransaction(emitter -> { (4)
            emitter.send(fruit); (5)
            return Panache.withTransaction(() -> { (6)
                return fruit.<Fruit>persist(); (7)
            });
        }).replaceWithVoid();
    }
}

import jakarta.inject.Inject;
import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.MediaType;

import org.eclipse.microprofile.faulttolerance.Bulkhead;
import org.eclipse.microprofile.reactive.messaging.Channel;
import org.hibernate.reactive.mutiny.Mutiny;

import io.smallrye.mutiny.Uni;
import io.smallrye.reactive.messaging.kafka.transactions.KafkaTransactions;
import io.vertx.mutiny.core.Context;
import io.vertx.mutiny.core.Vertx;

@Path("/")
public class FruitProducer {

    @Channel("kafka") KafkaTransactions<Fruit> kafkaTx;

    @Inject Mutiny.SessionFactory sf; (1)

    @POST
    @Path("/fruits")
    @Consumes(MediaType.APPLICATION_JSON)
    @Bulkhead(1)
    public Uni<Void> post(Fruit fruit) {
        return sf.withTransaction(session -> (2)
                kafkaTx.withTransaction(emitter -> (3)
                        session.persist(fruit).invoke(() -> emitter.send(fruit)) (4)
                ));
    }
}

import jakarta.inject.Inject;
import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.MediaType;

import org.eclipse.microprofile.faulttolerance.Bulkhead;
import org.eclipse.microprofile.reactive.messaging.Channel;

import io.quarkus.hibernate.reactive.panache.common.WithTransaction;
import io.smallrye.mutiny.Uni;
import io.smallrye.reactive.messaging.kafka.transactions.KafkaTransactions;

@Path("/")
public class FruitProducer {

    @Channel("kafka") KafkaTransactions<Fruit> kafkaTx;

    @POST
    @Path("/fruits")
    @Consumes(MediaType.APPLICATION_JSON)
    @Bulkhead(1)
    @WithTransaction (1)
    public Uni<Void> post(Fruit fruit) {
        return kafkaTx.withTransaction(emitter -> (2)
            fruit.persist().invoke(() -> emitter.send(fruit)) (3)
        );
    }
}

import jakarta.transaction.Transactional;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.reactive.messaging.Channel;

import io.quarkus.logging.Log;
import io.smallrye.mutiny.Uni;
import io.smallrye.reactive.messaging.kafka.transactions.KafkaTransactions;

@Path("/")
public class FruitProducer {

    @Channel("kafka") KafkaTransactions<Pet> emitter;

    @POST
    @Path("/fruits")
    @Consumes(MediaType.APPLICATION_JSON)
    @Bulkhead(1)
    @Transactional (1)
    public void post(Fruit fruit) {
        emitter.withTransaction(e -> { (2)
            // if id is attributed by the database, will need to flush to get it
            // fruit.persistAndFlush();
            fruit.persist(); (3)
            Log.infov("Persisted fruit {0}", p);
            e.send(p); (4)
            return Uni.createFrom().voidItem();
        }).await().indefinitely(); (5)
    }
}

kafka.bootstrap.servers=my-event-hub.servicebus.windows.net:9093 (1)
kafka.security.protocol=SASL_SSL
kafka.sasl.mechanism=PLAIN
kafka.sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required \ (2)
    username="$ConnectionString" \ (3)
    password="<YOUR.EVENTHUBS.CONNECTION.STRING>"; (4)

kafka.sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required \
    username="$ConnectionString" \
    password="Endpoint=sb://my-event-hub.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=XXXXXXXXXXXXXXXX";

mp.messaging.incoming.$channel.bootstrap.servers=my-event-hub.servicebus.windows.net:9093
mp.messaging.incoming.$channel.security.protocol=SASL_SSL
mp.messaging.incoming.$channel.sasl.mechanism=PLAIN
mp.messaging.incoming.$channel.sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required \
    username="$ConnectionString" \
    password="Endpoint=sb://my-event-hub.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=...";

kafka.bootstrap.servers=<connection url> (1)
kafka.security.protocol=SASL_SSL
kafka.sasl.mechanism=PLAIN
kafka.sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required \
  username="${KAFKA_USERNAME}" \ (2)
  password="${KAFKA_PASSWORD}"; (3)

apiVersion: v1
kind: Secret
metadata:
  name: kafka-credentials
stringData:
  KAFKA_USERNAME: "..."
  KAFKA_PASSWORD: "..."

%prod.quarkus.openshift.env.secrets=kafka-credentials