denis019 / drink-ordering-system

Drink ordering system

Architecture overview

Highly decoupled and scalable services with DDD, CQRS and Event Driven Design

Order Service

Responsible for placing and retrieving orders

Barista Service

Responsible for order processing

Notification Service TODO

Responsible for sending user notifications
Will subscribe to barista topic for the finished orders and will send notifications

Infrastructure

Kafka message broker

Will be used for the communication layer between services
System will start with 3 kafka brokers and each topic will have 3 partitions

Zookeeper

Schema-registry

Will use avro schema for the kafka messages

Kafka init

Will initialize kafka topic

Postgresql

Each service will keep internal state into DB

Installation

Prerequisites

• docker version 20.10.17
• docker Compose version v2.10.2
• java version openjdk 17.0.2 2022-01-18
• maven version Apache Maven 3.6.3

Run infrastructure

• create local volumes with required permissions and spin of kafka, zookeeper, schema-registry and postgres

./bin/run-infra.sh

• recreate kafka topics

./bin/run-kafka_recreate_topics.sh

• build service images, this will build and create docker images for order-service and barista-service

mvn clean install

• run order services, this will run previously created service docker images

./bin/run-service.sh

Send some requests

You can send some requests

• create order

curl --location --request POST 'http://localhost:8181/orders' \
--header 'Content-Type: application/json' \
--data-raw '{
    "drinkType": "COFFEE",
    "drinkAdditions": [
        "MILK",
        "SUGAR"
    ]
}'

After order creation you can check barista.orders table to see when the order will be finished
Barista service has a scheduler and it will check every 5s for the orders to process

• find order

curl --location --request GET 'http://localhost:8181/orders/7c872b0c-f142-4978-8cf5-c1a7035f028f'

Services are logging events, so you can monitor how the messages are propagated between service

docker ps
docker logs <containerId> -f

You can also check postgres DB, barista and order schemas

host: localhost
port: 5432
user: postgres
password: admin

Run/Debug services via Intelij

You can run/debug services via Intelij by using local for active profiles
To run services locally, first run infrastructure

TODO

• Add tests
• Check some corner cases
• Implement notification service