How can you ensure an architectural design pattern is correctly implemented in an application?

There are often potentially three, five, or even seven patterns that could address the identified business needs. To narrow to the best option, consider the functional and non-functional needs, and the design culture. The ideal solution will align with the organization's principles. Create sketches of the top two or three architectures capable of solving the problem. Finally, assess these alternative design patterns based on customer priorities and system needs in collaboration with the team. Typically, disagreements arise not on the effectiveness of the solution but on its alignment with architecture principles, even if the team may not explicitly express it in those terms. Be sure to define or revisit these principles at the start.

Key points in Understanding the problem: - Requirement Gathering: Engage stakeholders to collect, document, and understand their needs and expectations. - Use Case Identification: Define and prioritize specific use cases, scenarios, or workflows to comprehend user interactions and system requirements. - Domain Modeling: Analyze the problem domain to identify key entities, their relationships, and interactions within the system. - Root Cause Analysis: Investigate existing problems or challenges to determine their underlying causes.

There is typically more than one way to solve a problem! I advocate the simple methodology of Facts > Decisions > Recommendations. 1) Gather the known facts, requirements, NFRs, assumptions, guardrails, etc. 2) Outline the various options with pros and considerations for each, plus supporting artefacts like visuals to convey the option. The idea is that an eventual Decision will need to be made by stakeholders. 3) Outline a Recommendation around a primary Decision to follow alongside the rationale / why behind that recommendation, plus any fallback Decisions. This may tie into any roadmap / delivery plans.

It's essential to have a clear comprehension of both the specific problem you're addressing and the architectural pattern you intend to use. This understanding should encompass the pattern's principles, advantages, and potential drawbacks, ensuring it aligns with your application's needs. For instance, choosing the microservices architecture for a system that requires high scalability must also consider the complexities it brings, like inter-service communication.

Once a pattern is chosen, it's crucial to consistently follow its defined conventions and rules. This includes maintaining proper separation of concerns, as seen in the MVC pattern, and ensuring components interact through well-defined interfaces. Deviating from these conventions can lead to a loss of the benefits the pattern offers.

This is the most important thing to follow. If you follow the conventions and standards, you are making it easier for the future. If you follow these, it will be a cakewalk for anyone who wants to read and understand or make changes to any piece of the existing code. If used wrongly, it may help you I the short term but it will be tough to maintain for sure.

Generally speaking, architectural patterns should be implemented tech- agnostic, reason being - today’s art is tomorrow’s legacy. That being said, picking the framework(the what) and how it’s implemented(the how) is something that should be regularly evaluated and reviewed. Ideally, should leverage open source frameworks with a decent community support wheee applicable!

Why tools, frameworks or libraries? Why can't we develop it ourselves? These are the questions that come to young engineers or non-tech managers/leaders/founders. It is always not about the control over a piece of standard code. You should always ask the below questions to yourself before trying to invent something. - Am I (Are my teammates) the expert(s) in the area or domain? - How much time and resources do we need to spend on developing a duplicate solution, testing it and maintaining it? - How are we planning for the maintenance of the same in the future (You will have to update the underlying tech versions, and fix compatibility issues with other applications and versions)? - Can we afford a waiting period for such transitions?

Utilizing tools and frameworks that complement the chosen architectural pattern can significantly ease its implementation. These tools can automate and streamline various aspects of the architecture, thereby enhancing development efficiency and pattern adherence.

Regular refactoring and code reviews are imperative to maintain the integrity of the architectural pattern as the application evolves. Utilizing code analysis tools helps identify deviations or anti-patterns, ensuring the architecture remains clean and effective.

Rigorous testing across various levels (unit, integration, system) ensures that the application adheres to both functional and non-functional requirements of the chosen architecture. Additionally, monitoring the application in production, especially in architectures like serverless, provides insights into performance and helps maintain compliance with service level agreements.

Logging and telemetry are critical in production systems. Knowing how the application is used, performance and behaviors will payback consistently.