What Is Application Refactoring in Cloud Migration?

Application refactoring is the process of redesigning your applications to fully take advantage of cloud infrastructure capabilities. Organizations have outdated applications running on on-premise infrastructure that limit operational efficiency and hinder innovation. Application refactoring involves modifying the application's architecture and partially or fully rewriting its code to meet modern requirements. It can be a time-consuming, costly, and complex process, but it brings the maximum long-term performance and cost savings compared to other application modernization initiatives.

In the cloud migration process, refactoring is one of several different cloud migration approaches for apps. Refactoring is implemented when the application is critical and frequently used and modification can introduce added efficiencies. Example scenarios include:

Increased application demands

The performance and scalability demands on the application are increasing, but meeting those demands with current architecture is no longer possible. It is becoming increasingly more challenging to address customer needs and market demands with the current application as the app is under-performant, unscalable, or cost-intensive to run.

Maintenance challenges

The application is difficult to maintain because its source code is unavailable or is poorly written, unmaintained, or uses legacy technologies and languages. There may be no one on the team with the required expertise to work with the spaghetti code. It may also be too expensive and challenging to recruit new talent with that expertise. There could also be too many bugs or other challenges that make the application difficult to maintain.

Testing challenges

The legacy application has low test coverage and it is challenging to add new tests. Any new features and modifications would impact overall application quality and create new bugs that won’t be caught until they reach production. In this case, application refactoring allows you to increase test coverage and integrate automated testing tools.

Custom applications

Refactoring applications is a viable option when you have custom-built applications with editable codebases or custom-coded extensions to commercial software. You may have to refactor if the commercial software has had significant upgrades. Consider application refactoring if the app would benefit from cloud platform services, tools, and functionality, but the code isn’t compatible. Refactoring is also necessary if you want to instrument the app to output telemetry data.

The business benefits of application refactoring depend on the project's goals.

Cloud integration

Application refactoring changes the structure or design patterns used within the app. For example, legacy monolith applications can be decomposed into microservices to run as a distributed, containerized app. An app could be refactored to include a comprehensive API. Such changes allow the application to run more efficiently on cloud infrastructure.

Maintainable code

Refactoring messy or outdated code makes it comprehensible to development teams. In this case, application refactoring helps with code readability, ensures faster and easier new development, and reduces technical debt.

Increased performance

Refactoring code allows for performance enhancements on new, target cloud computing architectures. It ensures the application is faster, more scalable, and less expensive to run. During code performance refactoring, instrumenting the code with telemetry outputs validates the effects of the changes on external behavior.

Enhanced security

Refactoring applications for security and compliance purposes becomes necessary in migration. For instance, an app may use outdated libraries or unmaintained dependencies that need to be updated or replaced. You can also choose to add extra security layers while you’re refactoring applications.

Application refactoring involves making changes to an app to help it perform better, whether across cloud integrations, software developer usability, runtime performance, or security and compliance. Refactoring applications typically does not change the underlying functionality or add new functionality. However, many businesses choose to extend functionality while the refactoring process is underway.

Source code refactoring

Source code refactoring involves making changes to an application’s existing code. The source code changes may include logical flows, structural changes, bug fixes, code consolidation, language or dependency updates, removal of unused components, and other modifications. Source code can also be refactored to leverage cloud-native technologies, such as containers and serverless infrastructure.

Database refactoring

Making changes to how an application’s data is stored is known as database refactoring. Database refactoring may involve updating versions, models, or even switching to a different database for cloud migration.

User interface refactoring

Organizations may choose to perform user interface refactoring while they’re undertaking overall code changes. For example, an application’s UI may be updated to reflect outdated information, or the application to visually align with the organization’s branding.

There are several refactoring techniques to choose from, depending on your migration goals and the expected uptake of public cloud services.

Minimum viable refactoring

Minimum viable refactoring involves making the smallest number of changes to the application so that it can run in the cloud. Here, when you refactor code, it may include operating system updates, framework updates, new security changes, updated access permissions, and database changes.

Cloud-native refactoring

Cloud-native refactoring refers to making changes to the application to ensure it is easily integrated with cloud native features. This may include tasks such as adding telemetry for integration with Amazon Managed Grafana, introducing new functionality for data analytics, creating hooks for development with AWS CodePipeline, or defining infrastructure as code for CI/CD processes.

Containerization refactoring

A primary goal of some application refactoring projects is to convert a monolithic application into one that’s containerized instead. Containerization refers to an application composed of services that run in separate but orchestrated containers. With containerization, businesses can run applications across multiple servers in multiple locations and ensure the app is fully scalable and more resilient. Services such as Amazon Elastic Container Service and Amazon Elastic Kubernetes Service are designed specifically for container-based applications.

Serverless application refactoring

Another common application refactoring strategy when migrating to the cloud is converting an application into a serverless app. Serverless apps are event-driven, meaning that you can reduce costs by only running functions when they are triggered, without worrying about servers. Shifting to an event-driven architecture may or may not make sense, depending on your application type. AWS Lambda is the serverless compute service on AWS for your refactored cloud native application.

AWS offers a range of services that will help refactor your code to take advantage of the benefits of the cloud environment. For example, you can use

• AWS Toolkit for .NET Refactoring is a Visual Studio extension that reduces the time and effort required for developers to refactor legacy .NET applications to cloud-based alternatives on AWS.

• AWS Microservice Extractor for .NET simplifies the process of re-architecting older monolithic applications into smaller code projects to build a microservices-based architecture.

• AWS Mainframe Modernization Refactor with AWS Blu Age automatically creates modern applications from legacy, monolithic mainframe or midrange source code. Applications in COBOL, generated COBOL, PL/1, NATURAL, RPG/400, COBOL/400, and their respective underlying databases and data files.

• Amazon Q Developer is an assistant AI service that operates across .NET, mainframe, VMware, and Java workloads. It helps accelerate modernization projects and reduce costs by automating complex tasks such as legacy code analysis, documentation, language upgrades, vulnerability remediation, option exploration, and modernization wave execution.

Get started with application refactoring for cloud migration on AWS by creating an account today.