From f81962e03ef5ada8426fb069073ae38e877dd4ac Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Mon, 18 Jul 2022 22:48:26 +0200
Subject: [PATCH] splitter: 1.0.0-spring-ingetration - added an interceptor for
 logging

* Added a global interceptor, that uses `WireTap` to copy the messages
  to a special channel for logging, named `messageLog`.
* Added a `LoggingHandler`, that logs the messages, that are accumulated
  in the new channel `messageLog`.
---
 .../splitter/SplitterApplication.java         | 30 +++++++++++++++++++
 src/main/resources/application.properties     |  1 +
 2 files changed, 31 insertions(+)

diff --git a/src/main/java/de/juplo/kafka/wordcount/splitter/SplitterApplication.java b/src/main/java/de/juplo/kafka/wordcount/splitter/SplitterApplication.java
index 7087ed1..3dcb443 100644
--- a/src/main/java/de/juplo/kafka/wordcount/splitter/SplitterApplication.java
+++ b/src/main/java/de/juplo/kafka/wordcount/splitter/SplitterApplication.java
@@ -10,8 +10,12 @@ import org.springframework.expression.common.LiteralExpression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.integration.annotation.ServiceActivator;
 import org.springframework.integration.annotation.Transformer;
+import org.springframework.integration.channel.DirectChannel;
+import org.springframework.integration.channel.interceptor.WireTap;
 import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.config.GlobalChannelInterceptor;
 import org.springframework.integration.core.MessageProducer;
+import org.springframework.integration.handler.LoggingHandler;
 import org.springframework.integration.kafka.inbound.KafkaMessageDrivenChannelAdapter;
 import org.springframework.integration.kafka.outbound.KafkaProducerMessageHandler;
 import org.springframework.integration.transformer.HeaderEnricher;
@@ -24,7 +28,9 @@ import org.springframework.kafka.listener.KafkaMessageListenerContainer;
 import org.springframework.integration.kafka.channel.SubscribableKafkaChannel;
 import org.springframework.kafka.config.KafkaListenerContainerFactory;
 import org.springframework.kafka.listener.AbstractMessageListenerContainer;
+import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageHandler;
+import org.springframework.messaging.support.ChannelInterceptor;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -107,6 +113,30 @@ public class SplitterApplication
 		return channel;
 	}
 
+	@Bean
+	MessageChannel messageLog()
+	{
+		return new DirectChannel();
+	}
+
+	@GlobalChannelInterceptor
+	@Bean
+	ChannelInterceptor globalLoggingWireTap(MessageChannel messageLog)
+	{
+		return new WireTap(messageLog);
+	}
+
+	@Bean
+	@ServiceActivator(inputChannel = "messageLog")
+	public LoggingHandler logging()
+	{
+		LoggingHandler adapter = new LoggingHandler(LoggingHandler.Level.DEBUG);
+		adapter.setLoggerName("MESSAGE_LOG");
+		adapter.setLogExpressionString("headers.id + ': ' + payload + ', headers=' + headers");
+		return adapter;
+	}
+
+
 	public static void main(String[] args)
 	{
 		SpringApplication.run(SplitterApplication.class, args);
diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
index 94e7492..f1be16b 100644
--- a/src/main/resources/application.properties
+++ b/src/main/resources/application.properties
@@ -1,5 +1,6 @@
 server.port=8086
 management.endpoints.web.exposure.include=*
+logging.level.root=DEBUG
 logging.level.de.juplo.kafka.wordcount.splitter=DEBUG
 spring.kafka.consumer.auto-offset-reset. earliest
 spring.kafka.consumer.group-id=splitter
-- 
2.20.1