The monolith vs microservices debate is one of the most discussed topics in software architecture. It is a debate about how to structure software applications and services to be more efficient, scalable, and manageable. While some argue in favor of a monolithic architecture, others prefer a microservices-based approach. To understand this debate, it’s important to examine the theory of complexity, which can provide insights into the benefits and drawbacks of each approach.
At its core, the theory of complexity is concerned with the behavior of complex systems. It considers the various components and their interactions, and how they affect the system as a whole. The theory of complexity can be applied to software architecture by examining the different levels of complexity in software systems. These levels include components, systems, and anthropotechnic complexity.
Components complexity refers to the complexity of individual software components, such as classes, functions, and modules. In a monolithic architecture, all components are tightly coupled, meaning they are dependent on one another. This creates a high level of components complexity, as any changes to one component can have unintended consequences on other components. In contrast, a microservices architecture separates components into smaller, independent services. This reduces components complexity by limiting the interactions between components and making it easier to manage and maintain each service individually.
System complexity refers to the complexity of the interactions between components in a software system. In a monolithic architecture, system complexity can be high because all components are interdependent. Any change to one component can have ripple effects throughout the system, making it difficult to manage and scale. In contrast, a microservices architecture reduces system complexity by isolating each service and limiting the interactions between them. This makes it easier to manage and scale the system as a whole.
Anthropotechnic complexity refers to the complexity of human interactions with software systems. This includes issues related to usability, maintainability, and scalability. In a monolithic architecture, anthropotechnic complexity can be high because any changes to the system can have a wide range of impacts on the user experience. This can make it difficult to maintain and scale the system. In contrast, a microservices architecture reduces anthropotechnic complexity by allowing for more focused and targeted changes to individual services. This makes it easier to maintain and scale the system without negatively impacting the user experience.
The monorepo vs polyrepo debate is another topic that is closely related to the monolith vs microservices debate in software architecture. The monorepo debate is concerned with how to manage the codebase of a software system. A monorepo, short for a monolithic repository, is a single repository that contains all the code for a software system. In contrast, a polyrepo, short for a polyglot repository, is a set of separate repositories that contain the code for different parts of the system.
Like the monolith vs microservices debate, the monorepo vs polyrepo debate is also connected to the theory of complexity. In a monorepo, all the code for a system is located in a single repository, which can make it easier to manage and maintain the codebase. This is because developers have a single point of reference for the entire system, which can make it easier to understand how different parts of the system work together. Additionally, a monorepo can make it easier to manage dependencies between different parts of the system, as all the dependencies can be managed in a single repository.
However, a monorepo can also have drawbacks in terms of complexity. For example, if the codebase becomes too large, it can be difficult to manage and build, which can lead to longer build times and slower development cycles. Additionally, if there are multiple teams working on different parts of the system, conflicts can arise when multiple developers are working on the same codebase.
In contrast, a polyrepo can reduce some of the complexity associated with managing a large codebase. By separating the codebase into multiple repositories, developers can more easily manage and build each part of the system independently. This can also make it easier for multiple teams to work on different parts of the system without conflicts.
However, a polyrepo can also have its own drawbacks. For example, managing dependencies between different parts of the system can be more difficult in a polyrepo because there are multiple repositories to manage. Additionally, it can be more difficult to understand how different parts of the system work together because the code is located in separate repositories.
In conclusion, the monorepo vs polyrepo debate is supported by the theory of complexity, as both approaches have their own benefits and drawbacks in terms of managing the complexity of a software system. Ultimately, the choice between a monorepo or polyrepo depends on the specific needs of the development team and the software system they are working on. Similarly, the monolith vs microservices debate is also connected to the theory of complexity, which provides insights into the benefits and drawbacks of each approach. Monolithic architectures have higher levels of components and system complexity, which can make them more difficult to manage and scale. In contrast, microservices architectures reduce complexity at both the component and system levels, making them more manageable and scalable. Additionally, microservices architectures also reduce anthropotechnic complexity by allowing for more focused and targeted changes to individual services. Ultimately, the choice between a monolithic or microservices-based architecture depends on the specific needs of the software system and the goals of the development team.