Microservices implementation

This repository contains an example implementation of microservices for a fictional lending company. I created this in 2018 when I was discussing as a potential employment to showcase what can be done with Java, Sprint-boot and GraphQL.

As the code has been written in 2018 it doesn't use up-to-date dependencies but I share this in case it can be useful to someone.

Project structure

• the microservices directory contains a Spring-boot starter that configures common things used by all other microservices (like logging format, automatic propagation of authentication JWT token via Feign client, JSON parser configuration) and also a Gradle plugin (used by all microservices' build.gradle to setup common matters).
• the scoring-service directory contains a microservice that checks if a person can be given a loan or not (very simple implementation that checks if the monthly income is higher than a threshold).
• the user-service directory contains a service that manages user credentials. This is the service that contains the most documented code and APIs.
• the lending-service microservice manages the user lending account (currently only basic actions like withdraw and deposit) and uses scoring-service during the account opening procedure.
• frontend-service is a backend-for-frontend implementation that exposes data to the UI and also manages user sessions. It talks directly to user-service and lending-service and exposes a GraphQL interface.
• ui contains a React project for the web site.
• generator-microservice is a Yeoman generator that creates new microservice projects ready to be run.

Service dependencies

Requirements

• a Redis instance run on port 6379 (see the script inside docker/redis to start one in docker).
• a Zipkin instance run on port 9411 (see the script inside docker/zipkin to start one in docker).
• an environment variable MICROSERVICES_REPO_PATH pointing to a directory in the local file system where to host an artifact repository.