Messaging driven architecture with RabbitMQ

Stack

• Go 1.22.3
• RabbitMQ 3.13.6
• amqp091-go v1.10.0

Architecture

Order Service

• Handles the creation, updating, and retrieval of orders.
• Processes expired product reservations and payments.

Product Service

• Manages product reservations and cancellations.
• Ensures that products are reserved for orders.
• Handles the cancellation of reservations if needed.

Payment Service

• Processes payments for orders.
• Handles the payment actions.
• Ensures that payments are completed or failed.

RabbitMQ Setup

Exchanges

• order-action-exchange: Routes order-related action messages.
• order-result-exchange: Routes order-related result messages.
• dlx-exchange: Dead-letter exchange used to handle messages that cannot be processed.

Queues

• product-reservation-queue:
  • Holds messages for product reservation actions.
  • TTL: 15000 ms.
  • Configured DLX: dlx-exchange.
• payment-queue:
  • Holds messages for payment actions.
  • TTL: 60000 ms.
  • Configured DLX: dlx-exchange.
• product-reservation-result-queue: Holds messages for product reservation results.
• payment-result-queue: Holds messages for payment results.
• dlx-product-reservation-queue: Holds dead-letter messages for product reservation actions.
• dlx-payment-queue: Holds dead-letter messages for payment actions.

Order Processing Flow

Order Creation

1. Handle POST /orders request.
2. Create an order entity in the repository with status "Pending".
3. Publish an OrderAction message to order-action-exchange with routing key product-reservation-action-queue.
4. Return the order response with status "Pending".

Product Reservation

1. Consume messages from product-reservation-action-queue in product-service.
2. If the message expires, it will be routed to dlx-exchange with routing key dlx-product-reservation-action-queue.
3. order-service will consume expired messages from dlx-product-reservation-action-queue and mark the order as failed.
4. product-service will process the reservation and publish an OrderActionResult message to order-result-exchange with routing key product-reservation-result-queue.

Handling Product Reservation Result

1. Consume messages from product-reservation-result-queue.
2. If the reservation is successful, publish an OrderAction message to order-action-exchange with routing key payment-action-queue.
3. If the reservation fails, mark the order as failed.

Payment Processing

1. Consume messages from payment-action-queue in payment-service.
2. If the message expires, it will be routed to dlx-exchange with routing key dlx-payment-action-queue.
3. order-service will consume expired messages from dlx-payment-action-queue and mark the order as failed.
4. payment-service will process the payment and publish an OrderActionResult message to order-result-exchange with routing key payment-result-queue.

Order Service Handling Payment Result

1. Consume messages from payment-result-queue.
2. If the payment is successful, mark the order as completed.
3. If the payment fails, publish an OrderAction message to order-action-exchange with routing key product-cancellation-action-queue.

Product Cancellation

1. Consume messages from product-cancellation-action-queue in product-service to cancel the reservation.

Order Status Retrieval

1. Handle GET /orders/{id} request to retrieve the order status.

Order Service API

Endpoint: POST /orders

Request Body:

{
  "customerId": "123e4567-e89b-12d3-a456-426614174000",
  "cardId": "123e4567-e89b-12d3-a456-426614174003",
  "itemId": "123e4567-e89b-12d3-a456-426614174002",
  "price": 100
}

Responses:

201 Created

{
  "id": "ae5e5918-facb-40e5-bbdf-3525cedaaa7e",
  "customerId": "123e4567-e89b-12d3-a456-426614174000",
  "cardId": "123e4567-e89b-12d3-a456-426614174003",
  "itemId": "123e4567-e89b-12d3-a456-426614174002",
  "price": 100,
  "status": "pending",
  "message": "Order is pending"
}

400 Bad Request.

500 Internal Server Error.

Endpoint: GET /orders/{id}

Responses:

200 OK

{
  "id": "ae5e5918-facb-40e5-bbdf-3525cedaaa7e",
  "customerId": "123e4567-e89b-12d3-a456-426614174000",
  "cardId": "123e4567-e89b-12d3-a456-426614174003",
  "itemId": "123e4567-e89b-12d3-a456-426614174002",
  "price": 100,
  "status": "completed",
  "message": "Order is completed"
}

404 Not Found.

500 Internal Server Error.