Introduction

This is the result of my study on Microservices. It is an online shopping system and the details are here: https://ayhanavci.xyz/projects/Microservices/.

Implemented Concepts

• Microservices pattern
• CQRS
• Event Bus
• Event Store
• Database per Service
• Event Broker Pattern
• Saga - Choreography
• Reverse Proxy
• RESTful services

User Stories

Template: As a [ USER ] I want to [ ACTION ] So that [ REASONING ]

User Personas:

1. Customer
2. Product Manager

Features:

1. View Products
2. Shop
3. View Order Status
4. View User Profile
5. Get Invoice
6. Modify products, prices, stocks
7. Modify user credits

User Story	Acceptance Criteria
As a customer, I want to browse for products so that I can place an order.	View product categories View Products Ability to order each product Get an Invoice
As a customer, I want to view my past orders so that it guides my future purposes.	View orders. Display order status, product info, order date
As a customer, I want to view my profile information so that I can make adjustments.	View user information and credit Edit name, password, email
As a product manager, I want to add/edit/delete products so that customers can buy them	View/Add/Edit/Delete products. Names, prices, suppliers, units in stock
As a product manager, I want to view all customer order states so that I can assist if needed	View all orders and their states history in the system
As a product manager, I want to edit customer credit so that they can purchase products	View all users and their credit Edit credits

Modules

I used Python with Flask often because it is arguably one of the fastest and cleanest ways to prototype anything. I would implement everything in Python if I didn't want to introduce some variety. For Event Store, I used two docker containers. SDK to build for Linux, Runtime for deployment.

Module	Category	Programming Language	Sdk	Docker
ECommerce Website	Consumer	Python	Flask	python:alpine
Manager Website	Consumer	Python	Flask	python:alpine
Native Android Application	Consumer	Java	Android SDK	-
Accounting Database	Database	-	-	couchdb:latest
Customer Database	Database	-	-	redis:alpine
Event Store Database	Database	-	-	mongo mongo-express
Order Database	Database	-	-	postgres:alpine
Event Bus	Support Tool	-	-	rabbitmq:management
Event Store	Support Tool	C#	.NET Core 2.1	dotnet:2.1-sdk-alpine dotnet:2.1-aspnetcore-runtime-alpine
Reverse Proxy	Support Tool	-	-	nginx:alpine
Accounting Web Service	Web Service	Javascript	Node	node:alpine
Customer Web Service	Web Service	Python	Flask	python:alpine
Order Web Service	Web Service	Java	JDK-Jersey	maven:3.6-jdk-8-alpine
Product Web Service	Web Service	Python	Flask	python:alpine

Api by service;

Customer (Python)	Order Service(Java)	Product Service(Python)	Accounting Service(JS)
login-user	place-order	get-products	get-revenue
add-user	get-orders	get-all-products
update-user		get-product-details
get-user		add-new-product
get-all-users		update-product
get-credit		delete-product
set-credit		get-categories
		add-new-category
		update-category
		delete-category

Communication Topography

As follows;

Order Saga

The only Saga sample. Occurs when user places an order request for a product. Not all rollbacks are implemented. It looks messy but what happens here is: Customer places an order, If the customer has enough credit for the product price and if the product is in stock, the order succeeds.

Running the Project

All modules are prepared for Docker Compose. You need to create Docker networks written inside docker compose files, then run the compose files. The classic option is running compose from terminal. You need to repeat the following process for each module.

1. Open a terminal. Change directory to the module
2. Type docker-compose up

That's it. Everything should install inside its own container and run in there. Aside from Docker itself, you don't need to explicitly install anything else.

Only couchDB requires the following command after it starts:

curl -X PUT http://accounting_usr:[email protected]:5984/_users

Both websites run on ports 5001 and 5002 both of which you can edit from their yml files. On Android project, you need to open the settings (upper right corner) inside the app and change the IP / Host of the reverse proxy server.

Licence

MIT

Author

Ayhan AVCI 2018

[email protected]

ayhanavci.xyz