Application Design Patterns

Application design patterns are a set of rules that specify the organisation and structure of an application. These patterns help to ensure that systems are scalable, maintainable, and simple to comprehend by giving developers a standard language to use when discussing design choices. Applications can be created using a variety of design patterns, such as the monolithic, event-driven, and microservice patterns. Choosing the best pattern for a given application can significantly affect both its overall performance and development process. Each of these patterns has its own set of advantages and disadvantages.

Monolithic Application Design Pattern:

A monolithic application is a single, self-contained software system that consists of a single codebase, a single deployment unit, and a single runtime environment. All of the components of a monolithic application are tightly coupled, meaning that they are closely connected and dependent on each other. This makes it easy to develop, test, and deploy monolithic applications, as all of the code is contained within a single unit.

Pros:

Simple to develop and maintain: Monolithic applications are easy to develop and maintain because they have a single codebase and a single deployment unit. This makes it easy to understand the entire application and to make changes to it.
Easy to deploy: Monolithic applications are easy to deploy because they are a single unit. This means that they can be deployed to a single server or a cluster of servers with minimal effort.
Good for small applications: Monolithic applications are well-suited for small applications because they are simple to develop and maintain.

Cons:

Poor scalability: Monolithic applications can be difficult to scale because they are a single unit. If the application needs to handle a large number of users or a large amount of data, it may become slow or unresponsive.
Difficulty in adding new features: Monolithic applications can be difficult to modify or extend because all of the code is tightly coupled. This can make it difficult to add new features or make changes to the application without affecting other parts of the code.
Lack of modularity: Monolithic applications lack modularity because all of the code is contained within a single unit. This can make it difficult to reuse code or to build new applications using the same codebase.

Event-Driven Application Design Pattern:

An event-driven application is an application that is built around the concept of events and event-driven architectures. In an event-driven application, various components of the application communicate with each other by emitting and listening for events. This allows the application to be more flexible and scalable, as components can be added or removed without affecting the rest of the application.

Pros:

Good scalability: Event-driven applications are highly scalable because they are designed to handle large amounts of data and a large number of users. This makes them well-suited for applications that need to handle real-time data streams or large amounts of data.
Modularity: Event-driven applications are highly modular because they are built around the concept of events. This makes it easy to reuse code or to build new applications using the same codebase.
Loose coupling: Event-driven applications are loosely coupled because they are built around the concept of events. This makes it easy to add or remove components without affecting the rest of the application.

Cons:

Complex to develop: Event-driven applications can be complex to develop because they require a deep understanding of event-driven architectures and the concept of events.
Difficult to test: Event-driven applications can be difficult to test because they are highly modular and loosely coupled

Microservices Application Design Pattern:

A Microservice application design pattern is a software architecture that involves building an application as a collection of small, independent services that communicate with each other using well-defined interfaces. Each microservice is responsible for a specific function or set of related functions, and they can be developed and deployed independently of each other. This allows for greater flexibility and scalability, as it is easier to add or remove microservices without affecting the rest of the application.

Pros:

Scalability: Microservice applications are highly scalable because each microservice can be scaled independently of the others. This allows developers to scale only the microservices that are experiencing high levels of traffic, rather than the entire application.
Modularity: Microservice applications are highly modular because each microservice is a self-contained unit of functionality. This makes it easy to reuse microservices in other applications or to build new applications using the same codebase.
Improved fault tolerance: Microservice applications are more resilient to failures because if one microservice goes down, it will not affect the rest of the application. This means that the application can continue to function even if one or more microservices are experiencing issues.
Improved development speed: Microservice applications can be developed faster because each microservice can be developed and deployed independently of the others. This allows developers to work on different parts of the application concurrently, rather than having to wait for the entire application to be developed before testing and deployment.

Cons:

Complexity: Microservice applications can be more complex to develop and maintain because they require a deep understanding of microservice architecture and the concept of microservices.
Difficulty in testing: Microservice applications can be difficult to test because they are highly modular and loosely coupled. This can make it difficult to ensure that all of the microservices are working correctly together.
Increased infrastructure costs: Microservice applications may require more infrastructure resources because each microservice is a standalone unit that requires its own runtime environment. This can increase the costs of hosting and maintaining the application.
Increased complexity in deployment: Microservice applications may be more complex to deploy because each microservice must be deployed independently of the others. This can increase the time and effort required to deploy the application.

Regardless of what type of application you are designing you are likely going to need a modern scalable and resilient database to store your data. One of my favourite databases for this is a database called CockroachDB