Introduction

We proposed the FMSA (FHIR-based Microservice Architecture), a new open-source software architecture designed for medical informatics systems. And we developed this architecture to address the current lack of standardized microservice solutions in healthcare information systems.

Architecture

Development Steps

• If using the HTTP to expose FMSA, copying the docker-compose-http.yml to the docker-compose.yml file.
• Complete the docker compose environment building.
• Complete the api_gateway development and features including login, register, OAuth2 and rate time limit.
• Complete the PA implementation guide about scenario 1.

Docker Compose

• Running the docker compose up --build to run the FMSA.

Docker Stack Deployment

• Before running the docker stack deploy command, it should ensure the local Docker image has been built.
• If they're not deployed, it should run the docker compose build command firstly.
• If presenting Error response from daemon: This node is not a swarm manager. message, it should run the docker swarm init.
• If the FMSA is running via the docker compose up command, it should use the docker compose down.
• Running docker stack deploy -c docker-compose-stack-deploy.yml fmsa command to deploy the Docker stack.

The docker-compose-stack-deploy.yml is only for testing Docker Stack deployment

Development server

• The worker server is deployed in the PureVoltage (KVM-based VPS)
  • CPU: 4 cores
  • RAM: 16GB
  • HDD: QEMU HARDDISK 200GB
• The FMSA is deployed in the ColoCrossing (A dedicated server)
  • CPU: Intel(R) Xeon(R) CPU E3-1271 v3
  • RAM: 16GB
  • HDD: Samsung SSD 850 EVO 1TB

References

The proof of concept paper is as follows:

• C.-S. Li, S.-P. Ma, and T.-H. Lin, "FMSA: A Universal Microservice Architecture Based on FHIR Medical Informatics Standard," 2025 Second International Conference on Artificial Intelligence for Medicine, Health and Care (AIxMHC), pp. 42–49, Oct. 2025.

1. HAPI FHIR server installation and usage

• https://confluence.hl7.org/display/FHIR/Open+Source+Implementations

• https://confluence.hl7.org/display/FHIR/SMART+on+FHIR+server+implementations

• https://medium.com/impelsys/0f12c0cbbfdd

• https://medblocks.com/blog/terminologies-in-fhir#how-to-set-up-snomed-ct-on-hapi-fhir--8

• https://medblocks.com/blog/how-to-enable-fhir-profile-validation-with-hapi-fhir-jpa-server

• https://hapifhir.io/hapi-fhir/docs/v/7.6.0/tools/hapi_fhir_cli.html

  • https://hapifhir.io/hapi-fhir/docs/tools/hapi_fhir_cli.html

2. microservice scalability

• https://milaan.hashnode.dev/scaling-docker-containers-with-nginx-a-guide-to-reverse-proxy-and-load-balancing

3. Docker container hardware metrics

• https://gcore.com/learning/sysdig-what-it-is-and-how-to-use-it
• https://gcore.com/learning/troubleshooting-containers-with-sysdig-inspect
• https://www.cnblogs.com/apink/p/15767687.html
• https://onairotich.medium.com/understand-container-metrics-and-why-they-matter-9e88434ca62a

4. KeyCloak admin API

• https://medium.com/@imsanthiyag/44beb9011f7d
• https://www.stefaanlippens.net/keycloak-programmatically-create-clients-and-users.html
  • Tested versions are 21.0.2, 22.0.5 and 23.0.7.
• https://stackoverflow.com/questions/75776236/keycloak-session-and-token-timeouts

5. Upload file with FastAPI

• https://stackoverflow.com/questions/63048825/how-to-upload-file-using-fastapi

6. Docker stack deployment approach

• https://stackoverflow.com/questions/58666953

Troubleshooting

1. FHIR server hostname setting (Tomcat issue)

• The character [_] is never valid in a domain name
• https://blog.csdn.net/janet1100/article/details/121639158
• https://silcoet.ntunhs.edu.tw/FHIRSampleCode/Manual/HAPI%20FHIR%20Server_Linux.pdf

2. FHIR server upload-terminology issues

• hapifhir/hapi-fhir#3276
• hapifhir/hapi-fhir#4715