Scala Course Project 2020 - Skyeng platform

Сервис для изучения иностранных языков типа skyeng.ru

Ролевая модель: клиенты, преподаватели, администраторы

• Назначение уроков для клиентов
• Биллинг для клиентов и преподавателей

Service for learning foreign languages like skyeng.ru

Role model: clients, educators, administrators

• Assigning Clients Lessons
• Billing for clients and teachers

Architecture

Technology Stack

In the project given we will try to work with TypeLevel stack and see whether is it going to be possible to keep it as close to practices of FP programming. We are using:

• Http4s - as a web server
• Flyway - db migration service
• Doobie - for db access
• Circe - JSON serialisation
• Cats - FP data structures
• Circe Config - for app config
• Scala Check - for property based testing
• PostgreSQL - as a main database
• Tagless Final: For the core domain

Onion Architectural Pattern:

The project is being made following up Onion Architectural design principles. Using this approach we are decoupling our application modules into separate parts:

We are combining DDD with Onion together through following mechanisms:

Domain package. We tried to keep by dividing our modules in reasonable way. We use Services as straight forward interface to our domain. You can see quite a lot of boiler plate related to CRUD operations. We tried to keep one to one mapping between our Services and Endpoints.

In the domain module you will find following concepts:

1. Service - serves. Use cases that work with other domain conpets to realise your use-cases
2. Repository - ways to access to the data.
3. Models - stuff like classes, lessons, Student Profile and many many more... All the behaviour comes using Validation and Services

Modules:

• Controllers: Handle the logic of the incoming requests to our endpoints
• Domain: Module where we describe the core business logic. It consists of following:
  • Authentication - helps with authentication
  • Courses - course back-end logics, with related entities
  • Payment - payment service
  • Results - helper module, consists of entities which needed to evaluate Students' performance
  • Schedule - scheduling service that helps to students to choose the Classes
  • Users - has user, teacher, student services
• Infrastructure: contains the HTTP endpoints that we surface via http4s. You will also typically see JSON things in here via circe
• Configuration: contains the JDBC code, implementations of our Repositories. We have 2 implementations, an in-memory version as well as a doobie version.

The config package The config package could be considered infrastructure, as it has nothing to do with the domain. We use Circe Config to load configuration objects when the application starts up. circe config Provides a neat mapping of config file to case classes for us, so we really do not have to do any code.

DataBase scheme:

You can observe the scheme in the following link

Branch creation policy

1. Create Issue as following: SCP-###: Issue Title
2. Create Branch in issue as following: scp-###-issue-title

How to run?

Run following bash scripts to run the server application:

1. Built the project:

sbt docker:publishLocal

Once app is loaded, run second step to run the app:

docker-compose up -d --build

then

docker-compose logs -f

Testing

Application preruns the written into test package tests on gitlab CI/CD

In the test module of the applicaiton we are running tests basing on the

Application tests cover the endpoints behaviour of the application. It consists of typical command to see whether the services function as supposed to be.

All tests related to the endpoints that app provides to manipulate with the services.

User manual

For the better experience you should download the Postman to make following request.

Please, make sure that you have running server.

API to import into Postman: API

Sample requests

Desc	Verb	Route
Create user	POST	/user
Find user under certain ID	GET	/user/{id}
Delete user from the system	DELETE	/user/{id}
Create Course	POST	/course
Get course under certain ID	GET	/course/{id}