SERVICE_STARTUP.md

CNKart Service Startup

This repository can be started either manually or with Docker Compose.

Docker Compose

Use Docker Compose when you want the full stack with MySQL, Kafka, Eureka, item, inventory, and order services running together.

docker compose up --build

The exposed ports are:

• 8761 for discovery-server
• 8081 for item
• 8082 for order
• 8083 for inventory
• 3306 for MySQL
• 9092 for Kafka

Manual Startup

Use manual startup when you want to run the services one by one from your IDE or terminal.

1. Start MySQL and create the databases item_service, inventory_service, and order_service.
2. Start Kafka and make sure it is reachable on localhost:9092.
3. Start discovery-server on port 8761.
4. Start inventory on port 8083.
5. Start item on port 8081.
6. Start order on port 8082.

Request Flow

The recommended order flow is:

1. A client creates an order through the order service.
2. The order service stores the request in PENDING state and emits OrderCreated.
3. The order service asks inventory to reserve stock.
4. Inventory either reserves the quantity and emits InventoryReserved, or rejects the request and emits InventoryRejected.
5. If the reservation succeeds, the order service marks the order CONFIRMED and emits OrderConfirmed.

Notes

• The Docker Compose setup uses environment variables so the services can also run outside containers without editing source files.
• The reservation flow is intentionally kept as a separate step so it is easy to extend with downstream consumers later.