BAEL-8967: implementation for shared test broker

spring-kafka-4/src/main/java/com/baeldung/kafka/sharedbroker/Application.java

@@ -0,0 +1,12 @@
+package com.baeldung.kafka.sharedbroker;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+}

spring-kafka-4/src/main/java/com/baeldung/kafka/sharedbroker/OrderListener.java

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+package com.baeldung.kafka.sharedbroker;
+
+import static org.apache.kafka.clients.admin.AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG;
+
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+
+import org.apache.kafka.clients.admin.AdminClient;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.stereotype.Component;
+
+@Component
+public class OrderListener {
+
+    private static final Logger LOG = LoggerFactory.getLogger(OrderListener.class);
+    private final static CountDownLatch latch = new CountDownLatch(1);
+
+    @Value("${spring.kafka.bootstrap-servers}")
+    private String bootstrapServers;
+
+    @KafkaListener(topics = "order")
+    public void receive(ConsumerRecord<String, String> consumerRecord) throws Exception {
+        try (AdminClient admin = AdminClient.create(Map.of(BOOTSTRAP_SERVERS_CONFIG, bootstrapServers))) {
+            LOG.info("Received customer order request [{}] from broker [{}]", consumerRecord.value(), admin.describeCluster()
+                .clusterId()
+                .get());
+        }
+        latch.countDown();
+    }
+
+    public static CountDownLatch getLatch() {
+        return latch;
+    }
+}

spring-kafka-4/src/main/java/com/baeldung/kafka/sharedbroker/PaymentListener.java

@@ -0,0 +1,39 @@
+package com.baeldung.kafka.sharedbroker;
+
+import static org.apache.kafka.clients.admin.AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG;
+
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+
+import org.apache.kafka.clients.admin.AdminClient;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.stereotype.Component;
+
+@Component
+public class PaymentListener {
+
+    private static final Logger LOG = LoggerFactory.getLogger(PaymentListener.class);
+    private static final CountDownLatch latch = new CountDownLatch(1);
+
+    @Value("${spring.kafka.bootstrap-servers}")
+    private String bootstrapServers;
+
+    @KafkaListener(topics = "payment")
+    public void receive(ConsumerRecord<String, String> consumerRecord) throws Exception {
+        try (AdminClient admin = AdminClient.create(Map.of(BOOTSTRAP_SERVERS_CONFIG, bootstrapServers))) {
+            LOG.info("Received payment request [{}] from broker [{}]", consumerRecord.value(), admin.describeCluster()
+                .clusterId()
+                .get());
+        }
+        latch.countDown();
+    }
+
+    public static CountDownLatch getLatch() {
+        return latch;
+    }
+
+}

spring-kafka-4/src/test/java/com/baeldung/kafka/sharedbroker/EmbeddedKafkaHolder.java

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+package com.baeldung.kafka.sharedbroker;
+
+import org.springframework.kafka.KafkaException;
+import org.springframework.kafka.test.EmbeddedKafkaBroker;
+import org.springframework.kafka.test.EmbeddedKafkaKraftBroker;
+
+public final class EmbeddedKafkaHolder {
+
+    private static final EmbeddedKafkaBroker embeddedKafka = new EmbeddedKafkaKraftBroker(1, 1, "order", "payment").brokerListProperty(
+        "spring.kafka.bootstrap-servers");
+
+    private static volatile boolean started;
+
+    private EmbeddedKafkaHolder() {
+    }
+
+    public static EmbeddedKafkaBroker getEmbeddedKafka() {
+        if (!started) {
+            synchronized (EmbeddedKafkaBroker.class) {
+                if (!started) {
+                    try {
+                        embeddedKafka.afterPropertiesSet();
+                    } catch (Exception e) {
+                        throw new KafkaException("Embedded broker failed to start", e);
+                    }
+                    started = true;
+                }
+            }
+        }
+        return embeddedKafka;
+    }
+}

spring-kafka-4/src/test/java/com/baeldung/kafka/sharedbroker/OrderListenerTest.java

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+package com.baeldung.kafka.sharedbroker;
+
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.test.EmbeddedKafkaBroker;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.testcontainers.shaded.org.awaitility.Awaitility;
+
+@SpringBootTest
+class OrderListenerTest {
+
+    private static final EmbeddedKafkaBroker broker = EmbeddedKafkaHolder.getEmbeddedKafka();
+
+    @Autowired
+    private KafkaTemplate<String, String> kafkaTemplate;
+
+    @DynamicPropertySource
+    static void kafkaProps(DynamicPropertyRegistry registry) {
+        registry.add("spring.kafka.bootstrap-servers", broker::getBrokersAsString);
+    }
+
+    @Test
+    void givenKafkaBroker_whenOrderMessageIsSent_thenListenerConsumesMessages() {
+        kafkaTemplate.send("order", "key", "{\"orderId\":%s}".formatted(UUID.randomUUID()
+            .toString()));
+        Awaitility.await()
+            .atMost(10, TimeUnit.SECONDS)
+            .pollInterval(500, TimeUnit.MILLISECONDS)
+            .until(() -> OrderListener.getLatch()
+                .getCount() == 0);
+    }
+
+}

spring-kafka-4/src/test/java/com/baeldung/kafka/sharedbroker/PaymentListenerTest.java

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+package com.baeldung.kafka.sharedbroker;
+
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.test.EmbeddedKafkaBroker;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.testcontainers.shaded.org.awaitility.Awaitility;
+
+@SpringBootTest
+class PaymentListenerTest {
+
+    private static final EmbeddedKafkaBroker broker = EmbeddedKafkaHolder.getEmbeddedKafka();
+
+    @Autowired
+    private KafkaTemplate<String, String> kafkaTemplate;
+
+    @DynamicPropertySource
+    static void kafkaProps(DynamicPropertyRegistry registry) {
+        registry.add("spring.kafka.bootstrap-servers", broker::getBrokersAsString);
+    }
+
+    @Test
+    void givenKafkaBroker_whenPaymentMessageIsSent_thenListenerConsumesMessages() {
+        kafkaTemplate.send("payment", "key", "{\"paymentId\":%s}".formatted(UUID.randomUUID()
+            .toString()));
+        Awaitility.await()
+            .atMost(10, TimeUnit.SECONDS)
+            .pollInterval(500, TimeUnit.MILLISECONDS)
+            .until(() -> PaymentListener.getLatch()
+                .getCount() == 0);
+    }
+
+}