pacyL2K19/order-management-app

OMS

Order Processing System for E-commerce

Table of Contents

1. Introduction
2. System Overview
3. Microservice 1 - Order Management Service
   1. Responsibilities
   2. Interactions
4. Microservice 2 - Inventory Service
   1. Responsibilities
   2. Interactions
5. System Workflow
6. Use Cases 3. Order Processing
7. API Documentation
8. Deployment and Scalability
9. API Documentation
   1. Microservice 1 - Order Management Service
      1. Endpoints
   2. Microservice 2 - Inventory Service
10. Conclusion

Getting started

Prerequisites

• Java 8 or later
• Node.js 16 or later
• Docker
• Docker Compose

Running the application

1. From the root directory, build the docker images for the two microservices running the following command:

   docker-compose build -t order-processing-system .

2. Run the application using the following command:

   docker-compose up

3. The application will be running on http://localhost:8080

Introduction

The Order Processing System for E-commerce is designed to facilitate seamless order creation, modification, and processing for an e-commerce platform. This documentation provides an in-depth understanding of how the system functions, the roles of the two microservices involved, and key use cases.

System Overview

The system consists of two microservices:

1. Microservice 1 - Order Management Service
2. Microservice 2 - Inventory Service

Microservice 1 - Order Management Service

Responsibilities

• Handle order creation, modification, and processing.
• Communicate with the inventory service.

Interactions

• Expose RESTful APIs for order creation and management.
• Publish order events to Kafka for downstream processing.

Microservice 2 - Inventory Service

Responsibilities

• Manage inventory levels and product availability.
• Communicate with the order management service

Interactions

• Consume order events from Kafka for inventory updates.
• Publish inventory events to kafka if inventory levels are low, or if products are out of stock
• Publish inventory events to the OMS when updates are made to inventory levels

System Workflow

User Perspective

1. Customers place orders through the e-commerce platform - through a web application, mobile app, or other means (authentication and authorization services are not covered in this documentation)
2. Microservice 1 creates orders and publishes order events the inventory service through Kafka
3. Microservice 2 listens for order events, updates inventory, and coordinates communicate with the order management service - when inventory levels are low, or if products are out of stock, inventory events are published to Kafka - when the inventory updates are complete, inventory events are published to the order management service so order statuses can be updated - notification services are not covered in this documentation
4. Microservice 1 receives inventory events and updates order statuses accordingly
5. Each service has internal opertations that don't trigger events - for example, Microservice 1 may update order statuses when payment is processed, or Microservice 2 may update inventory levels when new products are added to the system
6. Product service, authentication / user service, and notification service are not covered in this documentation
7. Inter-service communication is handled through Kafka if the business logic requires it we can add an SSL encryption layer to the Kafka cluster to ensure data security

Technical Perspective

1. Microservice 1 receives order requests and creates orders.
2. Order events are published to Kafka for downstream processing.
3. Microservice 2 consumes order events, manages inventory, and coordinates back with Microservice 1.
4. Microservices can run, be sca, and be deployed independently

Use Cases

Order Processing

1. A customer selects products and initiates an order - Note that in a single order, we can have multiple products, and each product can have multiple quantities - we check and update orderItem status for each product upon order creation and inventory updates - default status is PENDING can be CANCELED if the inventory update fails or EXECUTED if the inventory update is successful
2. Microservice 1 creates an order and publishes an order event to Kafka.
3. Microservice 2 updates inventory levels.
4. Microservice 2 publishes inventory events to Kafka.
5. Microservice 1 receives inventory events and updates order statuses accordingly.

API Documentation

Detailed API documentation for Microservice 1 and Microservice 2 can be found in separate documents. These APIs cover order creation, modification, retrieval and inventory management

Deployment and Scalability

The system can be deployed in a containerized environment with orchestration (e.g., Docker and Kubernetes) to ensure scalability and high availability. Microservices can be replicated horizontally to handle increased loads.

API DOCUMENTATION

Microservice 1 - Order Management

Endpoints

• POST oms/orders - Create a new order
  • Body
    • userId - ID of the customer who placed the order
    • orderItems - List of order items
      • productId - ID of the product
      • quantity - Quantity of the product
  • Response
    • success - true if the order was created successfully
    • data - the order object
    • error - error message if the order creation failed
• GET oms/orders/{orderId} - Get an order by order ID
• PUT oms/orders/{orderId} - Update an order by order ID - can be used to update order status
  • Body
    • status - new status of the order
    • (optional) orderItems - list of order items to be updated
      • productId - ID of the product
      • quantity - Quantity of the product
      • status - new status of the order item
  • Response
    • success - true if the order was updated successfully
    • data - the order object
    • error - error message if the order update failed

Microservice 2 - Inventory

Listens to order events from Kafka and updates inventory levels accordingly

Conclusion

The Order Processing System for E-commerce provides a robust solution for efficient order management and processing. The collaboration between Microservice 1 and Microservice 2 enables seamless order handling and inventory management

This documentation serves as a comprehensive guide to understanding the system's architecture, functionalities, and key use cases, demonstrating how the two microservices work together to deliver a reliable and responsive e-commerce order processing system.