Antevenio's DDD Example App

This is a pet project for DDD and Clean/Hexagonal architecture concepts.

Index

1. Introduction
2. Domain/ Application / Infrastructure
3. Project setup
4. Services
5. Composer / Unit Tests
6. HTTP UI
7. Console UI
8. Metrics

Introduction

We are trying to find our own way to create apps. Some parts are based on awesome DDD examples that we have recently found on Github: dddinphp, jorge07/symfony-4-es-cqrs-boilerplate, CodelyTV/cqrs-ddd-php-example, and many others

Domain / Application / Infrastructure

Domain

With very simple Domain:

User(id, email) can be read and created.

Implemented concepts:

• Entities, ValueObjects, DomainEvents, Exceptions and Repositories.
• Model Validation with Assert
• UID generated with ramsey/uuid

Application

Actions: CreateUserAction and GetUserAction

• Action/Command Bus with Tactician and PDO transactional middleware.
• Event Store and Event Notifier with Prooph (PDO)
• Publishing Domain Events in a Rabbitmq Topic Exchange

Infrastructure

• UI
  • Http Handlers with Slim Framework
  • Console Commands with Symfony Console
• PSR's:
  • PSR-2 Coding Style Guide (codesniffer in composer.json)
  • PSR-3 LoggerInterface (implemented with Monolog)
  • PSR-4 Autoloader (autoload/autoload-dev in composer.json)
  • PSR-7 HTTP Messages (with Slim)
  • PSR-11 Container Interface (with Slim built-in container)
  • PSR-15 Http Handlers and Middlewares
• Metric's services implemented with Prometheus Client.
• Http Error Handler following API Problem specification.
• Environment config with zend-config
• Development environment with Docker

Project setup

1. Install docker
2. Clone this repo:

   git clone https://github.com/jbarroso/ddd-example 
   cd ddd-example

3. Start development environment with docker-compose

   export UID && docker-compose up -d

Services

• Access to the mysql database

  docker-compose exec mysql mysql -u myuser -psecret example

• Access to Rabbitmq (guest/guest) http://localhost:15672
• Access to Prometheus http://localhost:9090
• Access to Grafana (admin/admin) http://localhost:3000

Composer / Unit tests

Install dependencies (they are already installed with docker-compose up)

docker-compose run php composer install 

Check coding style and run unit tests (phpunit)

docker-compose run php composer check 

HTTP UI

Say hello world!

curl -v -X GET "http://localhost/hello"

Create a user

curl -v -X "POST" "http://localhost/user"  -H "Content-Type: application/json" -H "Accept: 1.0" -d '{"email":"[email protected]"}'

Get a user

curl -v -X GET "http://localhost/user?id=1958964c-724e-11e9-80e9-0242ac120004"

Console UI

List all available commands

docker-compose run php bin/console

Say hello world!

docker-compose run php bin/console hello-world

Get a user

docker-compose run php bin/console get-user 1958964c-724e-11e9-80e9-0242ac120004

Notify events to Rabbitmq exchange:

docker-compose run php bin/console notify-events

Start a Rabbitmq consumer listening to all events. For each event it will write a log entry in logs/app.log and also it will publis a counter metric with the event name in Prometheus.

docker-compose run php bin/console all-events-consumer

Start a Rabbitmq consumer listening to UserWasCreated event. It will write a log entry in logs/app.log.

docker-compose run php bin/console user-was-created-consumer

Metrics

Following Prometheus concepts we have: counters, gauges and histograms.

• The application exposes a /metrics endpoint for Prometheus and for testing porpouse it will update and publish a counter (example_some_counter), a gauge (example_some_gauge) and an histogram (example_some_histogram).
• Also we have a middleware to messure HTTP Request duration (LatencyMiddleware). It will publish example_request_duration_seconds histogram.
• AllEventsConsumer will increase a counter wit the event name (example_UserWasRead and example_UserWasCreated).
• And finally we have configured with Docker a Rabbitmq Prometheus exporter that you can consume in Grafana with this dashboard: Rabbitmq Graphana dashboard.