Building a Dynamic Gold Carding Module with Nest.js Microservices, NATS, Postgres & Docker

This repository comprises four essential services:

• api-gateway
• gold-card-microservice
• payer-microservice
• provider-microservice

Getting Started

Setting up this project locally on your system is straightforward with Docker.

1. Clone this repository and ensure you install each project's dependencies by executing npm run install.

2. Confirm Docker is operational, then run docker compose up --build -d to construct the container, images, and fetch the Postgres and NATS image from Docker.

3. This dockerfile includes Initialization Scripts for setting up pg_cron and scheduling the monthly auto approval check job. You can configure the job in /init-db/003-cron-job.sql.

4. Ensure all services are up and running. The API Gateway Server operates on port 3000.

5. Restore the backup database (dump_before_cron_14.sql.gz), containing the database schema and data.

Application Structure

HTTP API Gateway

This service utilizes both HTTP and NATS as sources to listen to requests. Serving as the entry point to the entire platform, it forwards requests by publishing a message to the NATS server, which then distributes it to its subscribers. All HTTP API endpoints are defined within this project.

Provider Microservice

This microservice features a createCptApproval event handler published to NATS and consumable by the GoldCard service. It facilitates the creation of a provider, CPT-code record, and their storage in the database.

Payer Microservice

Responsible for creating payer records and saving them to the database.

GoldCard Microservice

This microservice consumes the createCptApproval event, evaluates it using rules defined by the payer, and emits the CPT approval status to the provider. It also inserts records for gold-criteria-rules, provider-cpt-metrics, goldcard-evaluation-results, goldcard-eligibility, and provider-card-level, saving them to the database.