This project is a proof of concept for an event-based-shopping-system (EBSS) using Spring Boot and Apache Kafka. As a result of an article by Tobias Flohre, we decided to implement the event-based-system described in the blog. For more information I suggest you read up the article first.
- Blog article by Tobias Flohre https://blog.codecentric.de/2015/09/wer-microservices-richtig-macht-braucht-keine-workflow-engine-und-kein-bpmn/
- Inspiration: Movie Database https://github.com/tobiasflohre/movie-database
- Apache Kafka http://kafka.apache.org/
The final infrastructure will look like the following diagram:
You can use docker to get Kafka and Zookeeper up and running, or install the tools manually.
Clone repository:
git clone git@github.com:wurstmeister/kafka-docker.git
cd kafka-docker
Start a cluster:
docker-compose up -d
Add more brokers:
docker-compose scale kafka=3
Destroy a cluster:
docker-compose stop
Download code
wget http://mirror.netcologne.de/apache.org/kafka/0.8.2.0/kafka_2.10-0.8.2.0.tgz
tar -xzf kafka_2.10-0.8.2.0.tgz
cd kafka_2.10-0.8.2.0
Start Zookeeper
bin/zookeeper-server-start.sh config/zookeeper.properties
Start Kafka server
bin/kafka-server-start.sh config/server.properties
Before you can use Kafka and Zookeeper you need to figure out the right ports. Use docker-compose ps to find the dynamically created ports for all docker containers.
Each Spring Boot App contains a application.properties under src/resources. It is important that you update the port to match your local infrastructure, before using the Spring Boot Apps.
~/git/kafka-docker$ docker-compose ps
Name Command State Ports
----------------------------------------------------------------------------------------------------------------------
kafkadocker_kafka_1 /bin/sh -c start-kafka.sh Up 0.0.0.0:32777->9092/tcp
kafkadocker_kafka_2 /bin/sh -c start-kafka.sh Up 0.0.0.0:32778->9092/tcp
kafkadocker_kafka_3 /bin/sh -c start-kafka.sh Up 0.0.0.0:32779->9092/tcp
kafkadocker_zookeeper_1 /bin/sh -c /usr/sbin/sshd ... Up 0.0.0.0:32776->2181/tcp, 22/tcp, 2888/tcp, 3888/tcp
Step 1: Create a topic
Let's create a topic named "test" with a single partition and only one replica:
bin/kafka-topics.sh --create --zookeeper 192.168.99.100:32776 --replication-factor 1 --partitions 1 --topic test
We can now see that topic if we run the list topic command:
bin/kafka-topics.sh --list --zookeeper 192.168.99.100:32770
test
Step 2: Run the produces to send some messages
Run the producer and then type a few messages into the console to send to the server.
bin/kafka-console-producer.sh --broker-list 192.168.99.100:32777 --topic test
This is a message
This is another message
Step 3: Start a consumer
bin/kafka-console-consumer.sh --zookeeper 192.168.99.100:32776 --topic test --from-beginning
This is a message
This is another message
For more details see http://kafka.apache.org/documentation.html#quickstart
To build all Maven projects please run:
mvn clean install
To start the Spring Boot Apps use:
mvn spring-boot:run