Overview

This section will cover the approaches to implement and deploy the different FHIR resources and profiles as service.

Note

WSO2 Healthcare Solution offers two distinct solutions (Ballerina and Micro Integrator) each tailored to different architectural preferences. For systems that favor the Enterprise Service Bus (ESB) pattern, the Micro Integrator, enhanced with FHIR accelerators, can be utilized.
On the other hand, Ballerina, a programming language specifically designed for integrations, is ideal for implementing FHIR integrations structured as microservices.

BallerinaMicro Integrator

In this implementation pattern, each FHIR resource and profile is represented as an individual service (microservice). A separate Ballerina service will represent a FHIR Resource API. To implement FHIR APIs that support FHIR profiles, it's essential to provide endpoints that client applications can use to interact with your FHIR resources (for creating, reading, updating, deleting, and searching).

To streamline the setup of these APIs, we can use the Ballerina Health CLI Tool to generate the necessary API templates for a FHIR Facade. FHIR API developers can then write the business logic in the generated templates. The Health Tool is versatile and can be used to generate templates for various FHIR specifications such as base resources, USCore, AUBase etc.

Here's an example of how to utilize the Health Tool to generate USCore API templates

1. Start by cloning the example artifacts of particular FHIR profile and extracting them to a preferred location. This includes the ig-uscore/definitions directory, which includes the definition files of the FHIR specification.

2. For instance you can find all the latest version of US Core profiles here.

3. Navigate to the cloned directory and run the following command to generate the templates,

bal health fhir -m template -o genereated_outputs --org-name healthcare_samples --dependent-package ballerinax/health.fhir.r4.uscore501 ig-uscore/definitions

Explanaton

• -m [mode] - For this instance mode should be template
• -o [output directory] - Location of the generated Ballerina artifacts. If this path is not specified, the output will be written to the same directory from which the command is run.
• --org-name - Organization name of the Ballerina package/template to be generated.
• --dependent-package - Fully qualified name of the published Ballerina package containing IG resources (eg: <org>/<package>). This option can be used to generate templates specifically for the resources in the given IG. The package name part of this value will be added as a prefix to the template name. The dependent package should be prior generated and pushed to the ballerina central.

Notes

You can find all the core packages of different fhir profiles in the Ballerina central.

For instance:

• FHIR base resources
• US Core
• AU Base

If you want to generate packages for any custom profiles you can use Ballerina health package generation tool.

Notes

• While generating the templates, you can use --included-profile or --excluded-profile to include and exclude whaterver profiles you want.

1. After you have generated the templates, you should implement the business logic to fetch and process required data. Because, by default these templates do not have any business logic.

2. To run the service as a standalone server, execute the below command.

   bal run 
   

In this implementation pattern, each FHIR resource and profile is represented as an API. To implement the FHIR APIs, you will be able to use the relevant OAS definition of the FHIR resource. The OAS definition can be used to create FHIR APIs in the integration project.

Here's an example of how to create a FHIR API using the OAS definition of a FHIR resource.

1. Create a MI project using the MI VSCode plugin by following the guide on Creating a New Integration Project.

2. Create a REST API using the OAS definition of the FHIR resource. You can find the OAS definition of the FHIR resources from this location and download the relevant OAS definition.

3. There will be relevant endpoints in the OAS definition for creating, reading, updating, deleting, and searching the FHIR resources. You can use these created resources to start the implementation for FHIR interactions.