The goal of this project is to test, play and make experiments with various ways of using the graphql-java engine in a Spring Boot app. The simulated role of the service under test is a "domain aggregator", "frontend backend" or "gateway" - a service that calls downstream apis and processes their response in order to prepare and serve a unified model for an upstream website or report render.

The service under test it used to get all data that is required to print multiple reports (ranging in granularity) of a company car.

The Fleet Manager keeps data about cars in the fleet, The HR Database holds personal information of the assigned drivers and the integration with the Police Register provides us with some insight on the driving style and skill of the employees.

flowchart LR;
    graphql[graphql<br>service];
    start((client)) -- "carByLicencePlate()" --> graphql
    subgraph downstream
        fm["Fleet Manager"];
        hrdb["HR Database"];
        pr["Police Register"];
    end
    graphql--"GET /vehicles"-->fm;
    graphql--"GET /employees/:id"-->hrdb;
    graphql--"GET /driving-fines"-->pr;

The servcie is structured as a multi module gradle project:

• graphqltestbench:api - Graphql schema and exposed POJOs
• graphqltestbench:service - the service or domain layer: business logic, dtos to map downstream services responses, etc. Things that can be shared in each of the controller/application/graphql layer implementations.
• graphqltestbench:blockingservlet, graphqltestbench:asyncservlet, etc - different implementations of the graphql layer. These modules depend on the others and have main executable classes.

Other directories conain configuration for tools that are useful for testing

• ./downstream/ - a small node app - mocked implementation of the downstream service.
• ./artillery/ - load testing scenarios
• ./elk/ - docker compose config for an elk stack, is set up to consume logs from the service under test and the downsteam mock.
• ./prometheus/ - docker compose config for Prometheus and Grafana. Automatically scrape metrics from the service under test. Can also visualise Artillery's test resuts.

• to run the service: a java 17 jdk (with some small changes, the code should also compile to java 11)
• to run mocked downstream services & load testing tools: node + npm
• to run visualisation tools for logs and metrics: docker & docker-compose
• (optional) to run "handy commands": make

1. install Artillery for load testing:

   npm install -g artillery

2. launch ELK stack (Kibana on port 5601):

   cd ./elk && docker-compose up

3. launch Prometheus/Grafana (Grafana on port 3001):

   cd ./prometheus && docker-compose up

1. Launch downstream services: make run_downstream
2. Launch one of implementations: