Swiggy/Zomato Low Level System Design | Whiteboard explanation, UML, Code in Detail

Summary

The script outlines a detailed design for a food delivery system akin to Zomato, emphasizing system division into food and delivery subsystems. It discusses the roles of order, restaurant, and delivery managers, along with strategy patterns for assigning delivery partners. The presenter also shares insights on system extendibility and acknowledges potential improvements. Additionally, the script promotes an upcoming live system design course, inviting interested viewers to join.

Takeaways

• 📝 The video discusses the low-level design of a food delivery system, similar to Zomato, focusing on system design, UML diagrams, class relationships, and code details.
• 🎨 The presenter has designed the system themselves, acknowledging that there can be multiple approaches to solving the same system and highlighting alternative approaches and assumptions made during the design process.
• 👨‍🍳 The system is divided into two main subsystems: the food subsystem, responsible for menu display and food preparation, and the delivery subsystem, which handles the assignment of delivery partners and delivery logistics.
• 📑 The script details the roles of various classes within the system, such as the Order Manager, which coordinates between the food and delivery subsystems, and the Restaurant Manager, which oversees restaurant details and availability.
• 🏠 The design includes considerations for restaurant properties like location, owner information, and the ability for restaurants to set their availability status.
• 🍽️ The food subsystem involves classes like Menu, Dish, and Dish Add-on, with considerations given to customization options and the distinction between what constitutes a separate dish and an add-on.
• 🚗 The delivery subsystem uses strategies to match delivery partners to orders based on various factors such as location, ratings, and order volume.
• 🔄 The system design aims to be extendable to accommodate changes over time, such as the addition of new data fields or changes in the logic for assigning delivery partners.
• 🔒 The presenter emphasizes the importance of making the system design as flexible and extensible as possible to adapt to evolving requirements.
• 📚 The video also touches on design patterns such as Singleton for managing instances of managers and strategy patterns for selecting delivery partner assignment strategies.
• 👥 The script mentions different user types within the system, such as customers, delivery partners, and restaurant owners, and how they interact with the system.

Q & A

What is the primary focus of the video script?

The video script focuses on discussing the low-level design of a food delivery system, similar to Zomato, including subsystems for food preparation and delivery management.

What are the two major subsystems discussed in the script?

The two major subsystems discussed are the food subsystem, which handles restaurant menu display and food preparation, and the delivery subsystem, which manages the assignment of delivery partners.

What is the role of the Order Manager in the food delivery system?

The Order Manager is responsible for receiving orders, generating order IDs, and communicating with both the Food Manager and Delivery Manager to coordinate food preparation and delivery.

Why is the design of the system intended to be extendable?

The system is designed to be extendable to accommodate changing requirements and system decisions over time, ensuring that it can evolve continuously without major overhauls.

What design pattern is used for the Restaurant Manager and Food Manager classes?

The Singleton design pattern is used for the Restaurant Manager and Food Manager classes, ensuring that there is only one instance of each manager to handle their respective tasks.

What is the purpose of the Restaurant Manager class?

The Restaurant Manager class is responsible for managing all the restaurants, including providing the correct restaurant object based on the restaurant ID and handling details like menu, location, and availability.

How does the script address the issue of different objects for different branches of the same restaurant chain?

The script suggests creating different objects for every restaurant branch, as each branch can have unique details like location, owner, and menu, rather than considering them as part of a single object.

What is the significance of the composition relationship in the design of the food subsystem?

The composition relationship signifies that certain objects, such as a menu or a dish, cannot exist without their parent object, like a restaurant. This relationship is crucial for maintaining the integrity of the data and the system's design.

What is the role of the Delivery Metadata class in the delivery subsystem?

The Delivery Metadata class acts as a wrapper for all the data needed for delivery management, including user location, restaurant location, and order ID, making it easier to pass relevant information between components.

How does the script handle the assignment of delivery partners based on different strategies?

The script uses the Strategy design pattern, where different strategies for assigning delivery partners, such as location-based or rating-based strategies, implement a common interface. The Strategy Manager class decides which strategy to use based on the delivery metadata.