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This week’s issue brings you:

• Breaking Down Modular Monolithic Architecture: Blending Tradition with Innovation

• 7 Must Know Principles of Solution Architecture Design (Recap)

• Stateful vs Stateless Design (Recap)

• Connection Pooling Explained (Recap)

READ TIME: 5 MINUTES

Breaking Down Modular Monolithic Architecture: Blending Tradition with Innovation

Modular monoliths are becoming increasingly popular in the software engineering community, offering a balance between the simplicity of traditional Monoliths and the flexibility of microservices.

This architectural style elegantly addresses complex software challenges that arise in monolithic and microservices architecture, providing engineers with a streamlined approach to building software and maintenance.

By blending the best of both worlds, modular monoliths emerge as a compelling choice in today's diverse and demanding engineering environment.

Now, let's delve deeper into what exactly a modular monolith is and how it differentiates from its counterparts.

Understanding Modular Monoliths

Modular monoliths represent a unique blend in software architecture – they are monolithic systems yet designed with an emphasis on modularity.

This allows each component, or module, to be developed independently but function cohesively within a single, unified system.

The essence of a modular monolith is captured in its:

• Internal modularity: the system comprises many loosely coupled independent modules, each offering a cohesive set of functionalities within the larger system.

• Single deployable unit: despite modularization, it remains a single entity for deployment, mitigating the distributed operational complexity that comes with microservices.

• Shared database(s): modules typically interact with the same database(s), which simplifies data management and data integrity compared to the distributed database approach in microservices.

Modular monoliths strike a middle ground combining the straightforwardness of traditional monoliths with the modular flexibility of microservices, but without the operational complexity.

Advantages of Modular Monoliths

Simplified Complexity

Modular monoliths offer a straightforward architecture, making development and maintenance simpler than the often complex microservices approach. This simplicity is achieved through a unified codebase, which eliminates the intricacies of managing a distributed system. The result is a streamlined development process, allowing teams to focus on solving business problems rather than navigating operational complexities.

Improved Performance

In modular monoliths, the single-process architecture facilitates rapid communication between modules. This setup outpaces the slower network calls found in microservices, leading to significantly enhanced performance. Especially in scenarios demanding quick inter-module interaction, this efficiency is a key advantage, providing a smooth and responsive system.

Enhanced Data Consistency

The centralized data management approach in modular monoliths simplifies transaction handling, offering a stark contrast to the dispersed data management in microservices. This centralization ensures robust data integrity and consistency across the application, making it easier to maintain and safeguard the system's data quality and reliability.

Building a Modular Monolith

Building a modular monolith requires a careful balance of design principles and implementation strategies to ensure the system's efficiency and maintainability.

Central to this approach are loose coupling and high cohesion among modules, allowing each to operate independently within the larger system. Here are some examples:

• Product Catalog Module: Manages product listings and information.

• Payments Module: Handles all aspects of payment processing.

• Shipping Module: Oversees shipping logistics and tracking.

• Reviews Module: Manages customer reviews and feedback.

Designing these modules to be self-contained means that changes in one module have minimal impact on others, thus enhancing the system's stability and flexibility.

A crucial aspect of modular monoliths is establishing defined interfaces for communication between modules. These interfaces act as contracts, ensuring that modules interact consistently and predictably, simplifying interactions while maintaining module independence, a vital attribute for scalable and robust architecture.

In implementing a modular monolith, it's essential to focus on these clear boundaries and interfaces between modules. The goal is to create an architecture where changes in one module do not necessitate alterations in others.

Keeping an eye on future scalability and potential transitions to a Microservices architecture from the outset can also guide the initial design choices, ensuring that such transitions, if required, are smoother and more manageable.

Challenges and Considerations

While modular monoliths offer numerous benefits, they also present potential pitfalls that require careful consideration:

• Risk of tight coupling: If not designed with strict adherence to modularity principles, there's a risk of creating tight coupling between modules, which can negate the benefits of this architecture.

• Scaling challenges: Compared to Microservices, scaling a modular monolith can be more complex, especially in terms of handling large volumes of transactions or data.

To mitigate these challenges, certain best practices should be followed:

• Maintaining Modularity: Regular refactoring is crucial to prevent codebase bloat and ensure each module remains independent and focused.

• Strategies for Scaling: Planning for scalability from the outset is essential. This includes considering how the system might transition into microservices in the future if required.

The Rise of Modular Monoliths

The popularity of modular monoliths continues to rise. The combination of simplicity with modularity, scalable design, straightforward refactoring, as well as the ability to easily migrate to microservices are attractive attributes.

Martin Fowler aptly states, “You shouldn't start a new project with microservices, even if you're sure your application will be big enough to make it worthwhile.”

This perspective underscores the importance of considering modular monoliths, especially for projects where their distinct advantages align with the project's goals and complexities.

7 Must Know Principles of Solution Architecture Design (Recap)

Scalable — Solutions should be able to scale both vertically and horizontally.

Highly available and resilient — Design systems to be fault-tolerant and available even in the case of component failures, using redundancy and recovery strategies.

Performant —Optimize system performance by reducing latency, improving throughput, handling concurrency, and using caching effectively.

Secure — Security should be embedded at every layer of the architecture, including data encryption (at rest and in transit), access control, and regular monitoring for vulnerabilities.

Loosely Coupled — Design systems where components can function independently; allowing easier scaling, updates, and failure isolation.

Extendable — Designed to easily accommodate new features or functionalities without needing major rewrites.

Reusable — Components, services, or modules can be reused in different parts of the system. This reduces duplication of work, saves time, and improves consistency.

Check out the full post here for more details.

Stateful vs Stateless Design (Recap)

“State” refers to stored information that systems use to process requests.

Stateful applications store data like user IDs, session information, configurations, and preferences to help process requests for a given user.

As applications grew in complexity and received increasing amounts of traffic, the limitations of stateful design became apparent. The rapid need for scalability and efficiency drove the popularity of stateless design.

With stateless design, requests contain all the information needed to process it.

Stateless design has been pivotal in several areas including microservices and serverless computing.

It does have it’s challenges though including larger requests sizes, and transmission inefficiencies.

Most applications pick a hybrid approach between stateful and stateless design depending on the needs and constraints of each component of the system.

Check out the full post here for an extended breakdown stateless and stateful design.

Connection Pooling Explained (Recap)

Handling API requests often involves querying the database. Creating a new connection for each API call introduces unnecessary overhead.

Connection pooling mitigates this by reusing existing connections and reducing the overhead of establishing and closing connections.

This leads to faster response times and reduced resource consumption, making connection pooling a key technique for optimizing resource management and enhancing application performance.

So how does it work?

Connection pooling maintains a cache of reusable database connections, avoiding the need to create a new one each time.

When a connection is needed, an available connection from the pool is used, and when the task is completed, the connection is returned to the pool for future use.

See the full post here for a more detailed explanation, including key components and best practices.

That wraps up this week’s issue of Level Up Coding’s newsletter!

Join us again next fortnight where we’ll explore and visually distil more important engineering concepts.