Kafka POC

A very simple Spring Boot + Kafka proof of concept with a publisher, a simple subscriber and a stream processor.

Projects

• domain - Holds common domain events (only one in this PoC, OrderPlaced)
• publisher - Contains a REST endpoint where one can place an order, publishing an OrderPlaced event to the orders topic
• subscriber - Subscribes to the orders topic and prints OrderPlaced events to System.out
• processor - Subscribes to the orders topic and computes the number of orders placed by merchant

Running

1. Run docker-compose up on the root folder
2. Create the topic:

docker-compose exec broker kafka-topics \
   --create \
   --bootstrap-server localhost:9092 \
   --replication-factor 1 \
   --partitions 1 \
   --topic orders

3. mvn clean install all projects
4. Execute the generated jars with java -jar <jar-name>

Usage

Place orders with:

curl --location --request POST 'localhost:8080' \
--header 'Content-Type: application/json' \
--data-raw '{
    "merchantId": "string",
    "productId": "string"
}'

Orders will be printed on the terminal in which subscriber is running.

Number of orders per merchantId can be queried with curl --location --request GET 'localhost:8090'