From 25a3ac66cab49ebe30e2124a44625b56afb161ff Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Tue, 14 Dec 2021 20:13:41 +0100
Subject: [PATCH] Headers: a producer with audit-headers

---
 README.sh                                         | 10 +++++++---
 docker-compose.yml                                | 10 ++++++++++
 src/main/java/de/juplo/kafka/EndlessProducer.java |  7 +++++++
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/README.sh b/README.sh
index 0544297..de08fae 100755
--- a/README.sh
+++ b/README.sh
@@ -25,7 +25,11 @@ fi
 echo "Waiting for the Kafka-Cluster to become ready..."
 docker-compose exec kafka cub kafka-ready -b kafka:9092 1 60 > /dev/null 2>&1 || exit 1
 docker-compose up setup
-docker-compose up -d producer
+docker-compose up -d producer peter
 sleep 5
-docker-compose stop producer
-docker-compose logs producer
+docker-compose stop producer peter
+docker-compose exec -T cli bash << 'EOF'
+# tag::kcat[]
+kafkacat -C -b kafka:9092 -t test -o beginning -f'key: %k, headers: %h, value: %s\n' -e
+# end::kcat[]
+EOF
diff --git a/docker-compose.yml b/docker-compose.yml
index 10ad3a0..6f38efc 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -45,3 +45,13 @@ services:
       producer.client-id: producer
       producer.topic: test
       producer.throttle-ms: 200
+
+  peter:
+    image: juplo/endless-producer:1.0-SNAPSHOT
+    ports:
+      - 8081:8080
+    environment:
+      producer.bootstrap-server: kafka:9092
+      producer.client-id: peter
+      producer.topic: test
+      producer.throttle-ms: 666
diff --git a/src/main/java/de/juplo/kafka/EndlessProducer.java b/src/main/java/de/juplo/kafka/EndlessProducer.java
index 43b0e41..1620693 100644
--- a/src/main/java/de/juplo/kafka/EndlessProducer.java
+++ b/src/main/java/de/juplo/kafka/EndlessProducer.java
@@ -6,6 +6,8 @@ import org.apache.kafka.clients.producer.ProducerRecord;
 import org.apache.kafka.common.serialization.StringSerializer;
 
 import javax.annotation.PreDestroy;
+import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.util.Properties;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
@@ -66,6 +68,11 @@ public class EndlessProducer implements Runnable
             Long.toString(i)       // Value
         );
 
+        record
+            .headers()
+            .add("client", id.getBytes())
+            .add("i", BigInteger.valueOf(i).toByteArray()); // Printed as String by kafkacat
+
         producer.send(record, (metadata, e) ->
         {
           long now = System.currentTimeMillis();
-- 
2.20.1