High-level system overview

Requirements

• Java 11+
• Maven 3+
• Docker / docker-compose
• node/npm

API

Build

./mvnw clean package

Tests

Unit tests:

./mvnw test

Integration tests:

./mvnw integration-test

Test code coverage

To enable code coverage, simply enable the code-coverage Maven profile:

[...] -Pcode-coverage

./mvnw clean verify -Pcode-coverage

Code formatting

Code formatting is made using Spotless through its Maven plugin: https://github.com/diffplug/spotless/tree/main/plugin-maven It is automatically run at the process-sources, given the dev Maven profile is enabled (by default).

Development workflow

To spin up a development environment (MongoDB / RabbitMQ):

docker-compose up -d db broker

Run / deploy

Hosts setup

Edit your hosts file (/etc/hosts):

127.0.0.1 broker.localhost
127.0.0.1 api.localhost

Start containers

1. Build the users-management-api Docker image (in the users-management-api directory):

./mvnw clean package

Set the APP_USER_CREATION_IP_CHECK_ENABLED environment variable to false to disable IP check on user creation (docker-compose.yml)

2. Build the users-management-ui Docker image (in the users-management-ui directory):

npm install && npm run build-prod && npm run docker:build

3. Run

docker-compose up -d

This docker-compose.yml file starts 5 containers:

• Traefik proxy
• REST API server
• MongoDB
• RabbitMQ broker
• UI

4. Access the UI at http://localhost

5. Access the API documentation at http://api.localhost/swagger-ui.html

You can access the RabbitMQ dashboard at http://broker.localhost

API documentation

You can view Swagger-based API documentation at the following URL: http://localhost:8080/swagger-ui/index.html?configUrl=/v3/api-docs/swagger-config

Or http://api.localhost/swagger-ui/index.html?configUrl=/v3/api-docs/swagger-config if you are running the API through its Docker container.

Metrics

This application exposes some business metrics:

• Number of successful user creations: /actuator/metrics/users.creation.success
• Number of unsuccessful user creations: /actuator/metrics/users.creation.failure

Architecture

This project follows the screaming architecture: package by feature / functional area / bounded context

Advantages:

• Its structure is easy to read (screaming architecture, tells what it does), easy to search for a given use case
• Favors low coupling and high cohesion (bounded context): could easily be migrated to microservices later
• Allows working in parallel: each developer can work on its own feature; no merge conflicts
• SRP (Single Responsibility Principle): updating one feature doesn't interfere with other classes: minors regressions risks

Disadvantages:

• Can be complex/difficult at first glance (a lot of packages/classes)
• Lot of mapping / adapters: can be seen as a lot of duplication, however, it permits high isolation

Tests

Architecture tests are implemented by ArchUnit (see ArchitectureTests and CodingRulesTests)

Mapping strategy

Due to its architecture, this project extensively uses mapping through layers with MapStruct. As it's a simple CRUD project, mapping might have been skipped as it needs a lot of boilerplate code.

Such a mapping strategy can bring the following advantages:

• SRP (Single Responsibility Principle): a class should only have one reason to change
• No single entity class containing ORM/JSON/XML annotations
• Clean domain object

Database choice

MongoDB

As there is only one entity involved in this small application, there is no need to use a relational DB.

• Schema can easily evolve
• High throughput

UI

1. Set proper API URL in src/app/services/user.service.ts file (l.4) depending on your run configuration (http://localhost:8080 or http://api.localhost using Docker)

2. Build Angular application:

npm install && npm run build-prod

3. Don't forget to set the APP_USER_CREATION_IP_CHECK_ENABLED environment variable to false if you want to disable IP check on user creation (docker-compose.yml)

4. Build users-management-ui Docker image (you can also let docker-compose build it by adding the --build flag to the docker-compose up command):

npm run docker:build

5. Run:

docker-compose up -d

Go to http://localhost