Key Concept

Decoding Decoupled Architecture

Supply Chain Management and ‘Logical’ Application Views

What is a Decoupled Architecture?

Decoupled architectures are vastly different from traditional architectures. In a decoupled architecture, the term application can be confusing. When a monolithic application has been broken into dozens (if not hundreds) of independently deployed services, then what is the 'application?' Is a single component an application or is a collection of components an application? This article serves to define decoupled applications and review applications and their components in a collective view.

In the dynamic landscape of software development, architects and developers are constantly seeking innovative solutions to build scalable, flexible, and maintainable applications. One approach that has gained significant traction is decoupled architecture, where various components of an application are designed to function independently. Within this framework, managing logical application versions becomes a critical aspect to ensure seamless updates and improvements. In this article, we will explore the significance of logical application versions in a decoupled architecture and how it contributes to the overall success of a software system.

Understanding Decoupled Architecture

Decoupled architecture, often associated with microservices or modular design, is a paradigm that promotes the separation of different components or services within an application. Unlike traditional monolithic architectures, where a single codebase houses all functionalities, decoupled architectures break down the application into smaller, more manageable parts. Each component operates independently and communicates with others through well-defined APIs. Decoupled architectures provide organizations with a high level of business agility by allowing updates to the software to occur frequently by managing smaller work units.

decoupled architecture

Decoupled Architecture Components

  1. Microservices:
    • Microservices are small, self-contained services that focus on specific business functionalities.
    • Each microservice operates independently and communicates with others through APIs, enabling developers to make changes to one service without affecting the entire system.
  2. API Gateway:
    • An API gateway serves as a central entry point for external requests, managing the communication between different services.
    • It facilitates the routing of requests to the appropriate microservices, providing a unified interface to external clients.
  3.  AI Agents
    • An AI agent is a reusable component with artificial intelligence capabilities.
    • It performs a specific task or solves a problem, often by learning from and adapting to data and experiences.
  4. Message Brokers:
    • Message brokers, such as Kafka or RabbitMQ, facilitate asynchronous communication between services.
    • They enable events and messages to be sent and received, ensuring that different services can react to changes in the system without direct coupling.

Advantages of Decoupled Architecture

A decoupled architecture offers several advantages:

  1. Isolation of Changes:
    • Allows developers to make changes to a specific microservice without rebuilding the entire system.
    • This isolation enables more frequent updates and bug fixes, as changes are localized to the relevant component.
  2. Incremental Updates:
    • Updates can be rolled out incrementally, reducing the risk of system-wide failures.
    • Developers can introduce new features or improvements to specific services without disrupting the overall functionality of the logical application.
  3. Compatibility and Rollbacks:
    • Backward compatibility is maintained when making changes to a microservice’s API.
    • In case of unforeseen issues, rollbacks can be executed for specific services without reverting the entire logical application.

A Major Shift in How Software Solutions Are Developed and Deployed

With a decoupled architecture, the term “application” is sometimes used to represent a single service, and sometimes it represents a complete software solution delivered to an end-user. To clarify these concepts, the terms ‘Components’ and ‘Applications’ can be defined as:

  • Components: The individual pieces of the software supply chain, such as a microservice, database update, infrastructure change, file update, etc.
  • Applications: A collection of components delivered as a single software solution to end users.

In the monolithic world, the build step of the Continuous Integration workflow created the binaries that represent a version of a software project as a whole. The software components are compiled and statically linked into a single .jar, or a collection of .dlls and .exes. With a decoupled architecture, the linking is done dynamically at runtime via APIs. Component usage across different software projects defines your software supply chain. A collection of component versions delivered to end users is the logical application versions.

A decoupled architecture complicates tracking what components are consumed by each logical application. Knowing when and what changed is essential if an issue or vulnerability is found. IT teams must clearly understand how a single update impacts the overall software supply chain and who to notify if a vulnerability needs to be addressed.  IT teams must comprehensively view a single component’s blast radius to alleviate complexities in a decoupled architecture.

Complexities in Decoupled Archtecture

One of the complexities of component-based architecture is the loss of the application package and the ability to track changes in the application over time. Because components are loosely coupled, seeing how the application changes can be hard unless the updates are tracked with component versioning. Every new component version creates a new logical application version. IT Teams working in a decoupled architecture ask key questions about the software they deliver to end users. For example:

  • “What version of a component is this version of the application using?”
  • “Who is using my shared component?”
  • “When can I deprecate the component?”
  • “Who created this component?”
  • “What component version is running in each environment?”
  • “What open-source packages are used in the components my application consumes?”
  • “How do I generate a single application-level SBOM?”
  • “Are there vulnerabilities in the components my application consumes?”

Software supply chain practices must include this level of intelligence to provide answers to these questions in a decoupled architecture.  As the monolithic application is broken down into several independently deployed components, the need for tracking service-to-application relationships with version increases exponentially. Tracking a component update with versions is the safest and clearest way to manage change. In addition, the use of open source across all component versions must be easily viewable. While decoupled architecture has many advantages, it also increases the distribution of open source across hundreds of components. Mitigating a vulnerability in a single open-source package could require the updating of hundreds of independently deployed components.

Conclusion

Decoupled architecture offers many advantages over monolithic practices. However, decoupled architecture creates new complexities that need to be addressed for the successful implementation of decoupled applications.  Tracking decoupled applications and versioning their differences is necessary for understanding supply chain risk, blast-radius impact, and inventory usage across all environments. Software supply chain practices must manage logical application versions, based on the component versions consumed. Governing the changes to shared components as part of a supply chain strategy will be critical as changes as occur all day long.

DeployHub Simplifies a Decoupled Architecture by Restoring Logical Applications with Versions

A ‘logical’ application view is critical for understanding the supply chain of a single solution delivered to end-users. DeployHub defines a logical application based on the collection of component versions used. With DeployHub, development teams define their ‘Application Package’ in two ways: using the CI/CD command line interface (CLI) or via the application baseline designer. Developers can use the component baseline designer to define a logical view of their application’s Baseline Version.  The Application Baseline is then used to track and progressively version the application’s changes over time-based on updates to the underlying components. The CLI can integrate into your CI/CD pipeline to automatically create and increment the application version when a new version of a component is updated.

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Decoding Decoupled Architecture: The Rational Evolution of Logical Application Versions

Decoupled architecture offers many advantages. But with those advantages comes new challenges, particularly around understanding how a logical decoupled application is configured. In this article we explore the benefits and challenges of a decoupled architecture.

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Versioning components is an important process in simplifying a decoupled architecture. Learn how DeployHub tracks all of the configuration data related to each component, including SBOMs, ownership, and configuration metadata.

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