From c202f53a85f2f24e53b205c59bcfa6c4f17cf463 Mon Sep 17 00:00:00 2001
From: Marcin Grzejszczak <marcin@grzejszczak.pl>
Date: Thu, 23 Feb 2017 15:56:29 +0100
Subject: [PATCH] Showing a workaround to make message serializable

this issue is there in core of Spring Framework  (https://jira.spring.io/browse/SPR-15262) but this tests shows how to apply a workaround to get ridd of that problem until we bump up version of SF.

related to https://github.com/spring-cloud/spring-cloud-sleuth/issues/520 and https://github.com/spring-cloud/spring-cloud-sleuth/issues/523
SO - http://stackoverflow.com/questions/42277170/messagedeliveryexception-thrown-when-using-amqp-backed-channel-with-brixton-sr7

fixes #520
---
 .../TraceChannelInterceptorTests.java         | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptorTests.java b/spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptorTests.java
index e80bc69f2..0cf2c2e83 100644
--- a/spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptorTests.java
+++ b/spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptorTests.java
@@ -42,11 +42,16 @@ import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.core.MessagingTemplate;
 import org.springframework.integration.support.MessageBuilder;
 import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageHandler;
 import org.springframework.messaging.MessagingException;
+import org.springframework.messaging.support.ChannelInterceptor;
+import org.springframework.messaging.support.ChannelInterceptorAdapter;
+import org.springframework.messaging.support.GenericMessage;
 import org.springframework.messaging.support.MessageHeaderAccessor;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.util.SerializationUtils;
 
 import static org.junit.Assert.assertNotNull;
 import static org.springframework.cloud.sleuth.assertions.SleuthAssertions.then;
@@ -314,6 +319,28 @@ public class TraceChannelInterceptorTests implements MessageHandler {
 		then(TestSpanContextHolder.getCurrentSpan()).isNull();
 	}
 
+	@Test
+	public void serializeMutableHeaders() throws Exception {
+		Map<String, Object> headers = new HashMap<>();
+		headers.put("foo", "bar");
+		Message<?> message = new GenericMessage<>("test", headers);
+		ChannelInterceptor immutableMessageInterceptor = new ChannelInterceptorAdapter() {
+			@Override
+			public Message<?> preSend(Message<?> message, MessageChannel channel) {
+				MessageHeaderAccessor headers = MessageHeaderAccessor.getMutableAccessor(message);
+				return new GenericMessage<Object>(message.getPayload(), headers.toMessageHeaders());
+			}
+		};
+		this.tracedChannel.addInterceptor(immutableMessageInterceptor);
+
+		this.tracedChannel.send(message);
+
+		Message<?> output = (Message<?>) SerializationUtils.deserialize(SerializationUtils.serialize(this.message));
+		then(output.getPayload()).isEqualTo("test");
+		then(output.getHeaders().get("foo")).isEqualTo("bar");
+		this.tracedChannel.removeInterceptor(immutableMessageInterceptor);
+	}
+
 	@Configuration
 	@EnableAutoConfiguration
 	static class App {