🛒 Order Flow

This section describes how a customer's food order flows through the system, covering gRPC communication, Kafka topics, status transitions, and real-time updates.

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1. Search and Select Food

• The Customer searches for restaurants and food items.
• A gRPC call is made from the Customer Service to the Restaurant Service to retrieve restaurant and menu information.
• The customer browses the results and selects food items to place an order.

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2. Place Order

• After finalizing the selection, the customer places the order.
• The system:
  • Publishes order details to the Kafka topic: order-restaurant-request.
  • Persists the order in the Customer Service database.

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3. Restaurant Receives Order

• The Restaurant Service listens to the order-restaurant-request topic.
• It:
  • Extracts the order data.
  • Saves it in the Restaurant database.
  • Sends a notification to the restaurant UI/agent.

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4. Restaurant Responds to Order

• The restaurant can either accept or reject the incoming order.
• Upon action:
  • The system publishes an order status update to the Kafka topic: order-status with either "PLACED" or "REJECTED".
  • Both Customer and Restaurant Services subscribe to this topic to:
    • Update their databases.
    • Trigger UI notifications for status changes.

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5. Order Preparation and Rider Request

• If the order is accepted:

  • The Restaurant Service updates the order status to "PREPARED" and publishes it to the order-status topic.
  • Then, it publishes a rider request to the rider-request Kafka topic.

• The Rider Service listens to rider-request and initiates rider matching.

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6. Rider Notification

• Riders receive delivery request notifications in real-time.
• A rider can accept the request within a configured timeout window.

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7. Rider Selected

• When a rider accepts the delivery:
  • The order status is updated to "ONTHEWAY" and published to order-status.
  • The rider's live location is continuously published to the rider-location-updates topic.
  • The Customer Service consumes this topic to allow customers to track their delivery in real-time.

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8. Order Delivered

• After successful delivery:
  • The Rider Service updates the order status to "DELIVERED".
  • This is published to the order-status topic and synchronized across all involved services and UIs.

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