The O3 Single Page Application (SPA) represents a significant evolution in web application design, shifting from a monolithic structure to a more modular and extensible platform. Unlike its predecessor, O2, which served primarily as a reference example, O3 Spa is engineered to be a robust and adaptable product foundation. This transformation empowers implementations to build upon the core application, customizing and extending its functionality without needing to fundamentally alter the base framework. The goal is to streamline the development process, allowing teams to focus on unique implementation-specific features while leveraging the stable and feature-rich core of O3 SPA.

This incremental approach is crucial for efficient and scalable application development. The vision is to maintain a single configuration file, distro.properties, that orchestrates the build process via the SDK’s build-distro command. This centralized configuration method simplifies deployment and ensures consistency across different environments. While the transition to this fully realized state is ongoing, the backend of the Reference Application already embodies this principle, demonstrating the feasibility and effectiveness of this approach.

One of the key advancements in O3 SPA is addressing the need for frontend modularity, similar to the plug-and-play backend module system in traditional OpenMRS. In backend systems, adding functionality is as simple as placing an OMOD file in the modules directory. However, achieving this level of dynamic extensibility in a frontend SPA, delivered as static files, presents unique challenges. Historically, implementations had to define all desired applications and dependencies explicitly, often using a configuration file akin to spa-assemble-config.json. This method created friction when implementations aimed to incorporate updates or modifications from the reference application. The lack of a seamless way to integrate changes meant implementations had to manually track and merge updates, making upgrades complex and time-consuming.

The latest iterations of O3 SPA introduce a more streamlined and efficient solution. This new approach comprises two key components designed to enhance modularity and simplify deployment, paving the way for a more adaptable and customizable application ecosystem.

Docker Integration for O3 SPA Deployment

Embracing containerization through Docker has been a major push, recognizing its power to simplify deployments and ensure consistency across environments. The O3 SPA frontend is designed with Docker in mind, offering a reusable image that significantly eases deployment processes. To deploy a customized O3 SPA frontend, the primary step involves replacing the contents of the /usr/share/nginx/html/ directory within the Docker image with your specific static frontend files.

For instance, a docker-compose configuration can be used to mount a local directory containing your built frontend files into the container, effectively deploying your customized application. This approach allows for rapid iteration and deployment of O3 SPA applications.

Alternatively, for those who prefer to distribute their own Docker containers, a Dockerfile can be created to build upon the base O3 SPA frontend image. This Dockerfile would essentially remove the default frontend files and copy your customized frontend build into the image, creating a self-contained and distributable application package. Both methods highlight the flexibility and ease of deployment offered by Docker in conjunction with O3 SPA.

Future Enhancements for O3 SPA Customization

While the current improvements in O3 SPA deployment and modularity are substantial, further refinements are planned to enhance the developer experience and streamline customization workflows. The focus is on making these new features more accessible and user-friendly through enhancements in the SDK (Software Development Kit). Specifically, future development efforts will target:

• Extending the distro.properties file to include specifications for the frontend artifact version. This enhancement will enable the SDK to use the specified version as a foundation when building the frontend, ensuring version consistency and simplifying dependency management.
• Updating the SDK to generate Docker images based on the newer, optimized Docker images for O3 SPA. This transition will ensure that developers benefit from the latest improvements and best practices in containerization and deployment.
• Expanding the build-distro command within the SDK to support overriding existing distributions. This functionality will empower developers to easily customize and extend existing O3 SPA distributions, further promoting modularity and simplifying the development lifecycle.

These future steps are aimed at solidifying O3 SPA as a truly extensible and customizable web application platform, making it easier for implementations to tailor the application to their specific needs while benefiting from the robust and evolving core of O3 SPA.