Add stream (kafka, Rabbit) and Rsocket examples for Cloud Event

spring-cloud-function-samples/function-sample-cloudevent-stream/src/main/java/io/spring/cloudevent/DemoApplication.java

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+package io.spring.cloudevent;
+
+import java.net.URI;
+import java.util.function.Function;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.function.cloudevent.CloudEventHeaderEnricher;
+import org.springframework.cloud.function.cloudevent.CloudEventMessageBuilder;
+import org.springframework.cloud.function.cloudevent.CloudEventMessageUtils;
+import org.springframework.context.annotation.Bean;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.MessageBuilder;
+
+@SpringBootApplication
+public class DemoApplication {
+
+	public static void main(String[] args) throws Exception {
+	    SpringApplication.run(DemoApplication.class, args);
+	}
+
+	@Bean
+	public Function<Person, Employee> hire() {
+		return person -> {
+			Employee employee = new Employee(person);
+			return employee;
+		};
+	}
+
+	// uncomment while keeping the above POJO function
+//	@Bean
+//	public CloudEventHeaderEnricher cloudEventEnricher() {
+//		return messageBuilder -> messageBuilder.setSource("http://spring.io/cloudevent")
+//				.setType("sample").setId("987654");
+//	}
+
+	// uncomment while commenting the previous two beans
+//	@Bean
+//	public Function<Message<Person>, Message<Employee>> hire() {
+//		return message -> {
+//			Person person = message.getPayload();
+//			Employee employee = new Employee(person);
+//			return CloudEventMessageBuilder.withData(employee).setId("123456")
+//				.setSource(URI.create("https://spring.cloudevenets.sample")).build();
+//		};
+//	}
+}

spring-cloud-function-samples/function-sample-cloudevent-stream/src/main/java/io/spring/cloudevent/Employee.java

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+package io.spring.cloudevent;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Random;
+
+public class Employee {
+
+	private Person person;
+
+	private int id;
+
+	public Employee() {
+
+	}
+
+	public Employee(Person person) {
+		this.person = person;
+		this.id = new Random().nextInt(1000);
+	}
+
+	public Person getPerson() {
+		return person;
+	}
+
+	public void setPerson(Person person) {
+		this.person = person;
+	}
+
+	public int getId() {
+		return id;
+	}
+
+	public void setId(int id) {
+		this.id = id;
+	}
+
+	public String getMessage() {
+		return "Employee " + id + " was hired on " + new SimpleDateFormat("dd-MM-yyyy").format(new Date());
+	}
+}

spring-cloud-function-samples/function-sample-cloudevent-stream/src/main/java/io/spring/cloudevent/Person.java

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+package io.spring.cloudevent;
+
+public class Person {
+
+	private String firstName;
+
+	private String lastName;
+
+	public String getLastName() {
+		return lastName;
+	}
+
+	public void setLastName(String lastName) {
+		this.lastName = lastName;
+	}
+
+	public String getFirstName() {
+		return firstName;
+	}
+
+	public void setFirstName(String firstName) {
+		this.firstName = firstName;
+	}
+}

spring-cloud-function-samples/function-sample-cloudevent-stream/src/main/resources/application.properties

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+spring.cloud.function.definition=hire
+spring.cloud.stream.bindings.hire-in-0.binder=rabbit
+spring.cloud.stream.bindings.hire-out-0.binder=kafka

spring-cloud-function-samples/function-sample-cloudevent-stream/src/test/java/io/spring/cloudevent/DemoApplicationTests.java

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+package io.spring.cloudevent;
+
+import java.util.Collections;
+import java.util.Queue;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.kafka.clients.admin.AdminClient;
+import org.apache.kafka.clients.admin.KafkaAdminClient;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ConditionEvaluationResult;
+import org.junit.jupiter.api.extension.ExecutionCondition;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.springframework.amqp.rabbit.connection.CachingConnectionFactory;
+import org.springframework.amqp.rabbit.core.RabbitMessagingTemplate;
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.amqp.support.converter.Jackson2JsonMessageConverter;
+import org.springframework.amqp.support.converter.MessagingMessageConverter;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cloud.function.cloudevent.CloudEventMessageBuilder;
+import org.springframework.cloud.function.cloudevent.CloudEventMessageUtils;
+import org.springframework.cloud.function.context.config.JsonMessageConverter;
+import org.springframework.integration.kafka.inbound.KafkaMessageSource;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.listener.KafkaMessageListenerContainer;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageHeaders;
+import org.springframework.messaging.converter.CompositeMessageConverter;
+import org.springframework.messaging.support.GenericMessage;
+import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.util.MimeTypeUtils;
+
+@SpringBootTest
+@ExtendWith(DemoApplicationTests.TestRule.class)
+public class DemoApplicationTests {
+
+	@Autowired
+	private RabbitMessagingTemplate rabbitTemplate;
+
+	ArrayBlockingQueue<Message<String>> queue = new ArrayBlockingQueue<>(1);
+
+	@Test
+	public void test() throws Exception {
+
+		Message<byte[]> messageToAMQP = CloudEventMessageBuilder
+				.withData("{\"firstName\":\"John\", \"lastName\":\"Doe\"}".getBytes())
+				.setSource("https://cloudevent.demo")
+				.setHeader(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_JSON)
+				.build(CloudEventMessageUtils.AMQP_ATTR_PREFIX);
+
+		rabbitTemplate.send("hire-in-0", "#", messageToAMQP);
+
+		Message<String> resultFromKafka = queue.poll(2000, TimeUnit.MILLISECONDS);
+		System.out.println("Result Message: " + resultFromKafka);
+		System.out.println("Cloud Event 'specversion': " + CloudEventMessageUtils.getSpecVersion(resultFromKafka));
+		System.out.println("Cloud Event 'source': " + CloudEventMessageUtils.getSource(resultFromKafka));
+		System.out.println("Cloud Event 'id': " + CloudEventMessageUtils.getId(resultFromKafka));
+		System.out.println("Cloud Event 'type': " + CloudEventMessageUtils.getType(resultFromKafka));
+
+	}
+
+	@KafkaListener(id = "test", topics = "hire-out-0", clientIdPrefix = "cloudEvents")
+    public void listen(Message<String> message) {
+		queue.add(message);
+    }
+
+	public static class TestRule implements ExecutionCondition {
+		@Override
+		public ConditionEvaluationResult evaluateExecutionCondition(ExtensionContext context) {
+			try {
+				new CachingConnectionFactory("localhost").createConnection();
+				try {
+					KafkaAdminClient.create(Collections.singletonMap("bootstrap.servers", "localhost:9092"));
+				}
+				catch (Exception e) {
+					System.out.println("Kafka is not available on localhost:9092");
+					return ConditionEvaluationResult.enabled("Kafka is not available on localhost, default port");
+				}
+			}
+			catch (Exception e) {
+				System.out.println("RabbitMQ is not available on localhost:5672");
+				return ConditionEvaluationResult.disabled("Rabbit is not available on localhost:5672");
+			}
+
+
+			return ConditionEvaluationResult.enabled("All is good");
+		}
+	}
+}