From: Kai Moritz <kai@juplo.de>
Date: Tue, 14 Dec 2021 19:41:16 +0000 (+0100)
Subject: Round Robin: the producer uses round-robin for partitioning
X-Git-Tag: round-robin-DEPRECATED~1
X-Git-Url: http://juplo.de/gitweb/?a=commitdiff_plain;h=59e6285162b2b441f68c25ba4c969802faf44a2d;p=demos%2Fkafka%2Ftraining

Round Robin: the producer uses round-robin for partitioning
---

diff --git a/README.sh b/README.sh
index 0544297..9190bf0 100755
--- a/README.sh
+++ b/README.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-IMAGE=juplo/endless-producer:1.0-SNAPSHOT
+IMAGE=juplo/round-robin:1.0-SNAPSHOT
 
 if [ "$1" = "cleanup" ]
 then
@@ -24,8 +24,61 @@ 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 kafka-ui
+
+docker-compose exec -T cli bash << 'EOF'
+echo "Creating topic with 3 partitions..."
+kafka-topics --bootstrap-server kafka:9092 --delete --if-exists --topic test
+# tag::createtopic[]
+kafka-topics --bootstrap-server kafka:9092 --create --topic test --partitions 3
+# end::createtopic[]
+kafka-topics --bootstrap-server kafka:9092 --describe --topic test
+EOF
+
+docker-compose up -d producer
+sleep 10
+docker-compose stop producer
+docker-compose up count-0
+docker-compose up count-1
+docker-compose up count-2
+
+docker-compose exec -T cli bash << 'EOF'
+echo "Altering number of partitions from 3 to 7..."
+# tag::altertopic[]
+kafka-topics --bootstrap-server kafka:9092 --alter --topic test --partitions 7
+kafka-topics --bootstrap-server kafka:9092 --describe --topic test
+# end::altertopic[]
+EOF
+
 docker-compose up -d producer
-sleep 5
+sleep 10
+docker-compose stop producer
+docker-compose up count-0
+docker-compose up count-1
+docker-compose up count-2
+docker-compose up count-3
+docker-compose up count-4
+docker-compose up count-5
+docker-compose up count-6
+
+docker-compose exec -T cli bash << 'EOF'
+echo "Recreating topic with 7 partitions..."
+# tag::recreatetopic[]
+kafka-topics --bootstrap-server kafka:9092 --delete --topic test
+kafka-topics --bootstrap-server kafka:9092 --create --topic test --partitions 7
+kafka-topics --bootstrap-server kafka:9092 --describe --topic test
+# end::recreatetopic[]
+EOF
+
+docker-compose up -d producer
+sleep 10
+docker-compose stop producer
+docker-compose up count-0
+docker-compose up count-1
+docker-compose up count-2
+docker-compose up count-3
+docker-compose up count-4
+docker-compose up count-5
+docker-compose up count-6
+
 docker-compose stop producer
-docker-compose logs producer
diff --git a/docker-compose.yml b/docker-compose.yml
index 10ad3a0..c2c9bd6 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -24,24 +24,136 @@ services:
     depends_on:
       - zookeeper
 
-  setup:
-    image: juplo/toolbox
-    command: >
-      bash -c "
-        kafka-topics --bootstrap-server kafka:9092 --delete --if-exists --topic test
-        kafka-topics --bootstrap-server kafka:9092 --create --topic test --partitions 2
-      "
+  kafka-ui:
+    image: provectuslabs/kafka-ui:0.2.1
+    ports:
+      - 8080:8080
+    environment:
+      KAFKA_CLUSTERS_0_NAME: local
+      KAFKA_CLUSTERS_0_BOOTSTRAPSERVERS: kafka:9092
 
   cli:
     image: juplo/toolbox
     command: sleep infinity
 
   producer:
-    image: juplo/endless-producer:1.0-SNAPSHOT
+    image: juplo/round-robin:1.0-SNAPSHOT
     ports:
-      - 8080:8080
+      - 8000:8080
     environment:
       producer.bootstrap-server: kafka:9092
       producer.client-id: producer
       producer.topic: test
-      producer.throttle-ms: 200
+      producer.throttle-ms: 10
+
+  count-0:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 0 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
+
+  count-1:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 1 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
+
+  count-2:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 2 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
+
+  count-3:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 3 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
+
+  count-4:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 4 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
+
+  count-5:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 5 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
+
+  count-6:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 6 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
+
+  count-7:
+    image: juplo/toolbox
+    command: >
+      bash -c "
+        kafka-console-consumer \
+          --bootstrap-server kafka:9092 \
+          --topic test \
+          --partition 7 \
+          --property print.key=true \
+          --property print.value=false \
+          --from-beginning \
+          --timeout-ms 1000 2>/dev/null | sort | uniq -c
+      "
diff --git a/pom.xml b/pom.xml
index 7028cfd..9741146 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,8 +12,8 @@
   </parent>
 
   <groupId>de.juplo.kafka</groupId>
-  <artifactId>endless-producer</artifactId>
-  <name>Endless Producer: a Simple Producer that endlessly writes numbers into a topic</name>
+  <artifactId>round-robin</artifactId>
+  <name>Round Robin: a version of the Endless Producer, that uses round robin for partitioning</name>
   <version>1.0-SNAPSHOT</version>
 
   <dependencies>
diff --git a/src/main/java/de/juplo/kafka/EndlessProducer.java b/src/main/java/de/juplo/kafka/EndlessProducer.java
index 43b0e41..6b42954 100644
--- a/src/main/java/de/juplo/kafka/EndlessProducer.java
+++ b/src/main/java/de/juplo/kafka/EndlessProducer.java
@@ -45,6 +45,7 @@ public class EndlessProducer implements Runnable
     props.put("bootstrap.servers", bootstrapServer);
     props.put("client.id", clientId);
     props.put("acks", acks);
+    props.put("partitioner.class", "org.apache.kafka.clients.producer.RoundRobinPartitioner");
     props.put("key.serializer", StringSerializer.class.getName());
     props.put("value.serializer", StringSerializer.class.getName());