Evaluation task for Modus Create

Backend/server made as Evaluation task for Modus Create.

• application allow to manage your budget
• make monetary transactions asincome or an expense
• allow to consult the balance resulting from your financial transactions
• application support multiple users

Getting Started

Prerequisites

What things you need to install the software and how to install them

• Docker - Container Management. Version: 19.03+ and Docker Compose Version: 1.25+
• Maven - Dependency Management
• Java - OpenJDK 8 or similar OracleJDK 8

Installing

A step by step series of examples that tell you how to get a env running

Go to:

cd %project_parent_directory%/app

Execute

./build.sh

It will build project, run all tests

Running

Go to:

cd %project_parent_directory%/app

Execute

To start app:

./run.sh start

It will run all needed environment

To start infrastructure-only:

./run.sh start-infrastructure

Now you can play with code, run microservices from IDE, build tests etc.

To stop app:

./run.sh stop

To remove/cleanup app run

./run.sh remove

Using

Go to:

cd %project_parent_directory%/app

Usage commands:

Get help

./app.sh -h

Register new user

./app.sh -l %wanted_login% -p %wanted_password% -r

Login/Authorize (you will receive JWT token that needed for making transactions and getting balance)

./app.sh -l %your_login% -p %your_password% -a

Make income transaction (-i key) (value for -m parameter should be positive INTEGER).

./app.sh -j %your jwt token from auth% -m %wanted monetary INT value% -i -t

Make expense transaction (-e key) (value for -m parameter should be positive INTEGER). You can have negative balance if you expense too much ;)

./app.sh -j %your jwt token from auth% -m %wanted monetary INT value% -e -t

Check your balance

./app.sh -j %your jwt token from auth% -b

List of parameters:

• -h help flag. Without value
• -r register flag. Allow you to register. Without value. Should goes in the end of command
• -l login flag. Should goes with your login
• -p password flag. Should goes with your password
• -a authorization flag. Allow you to get jwt token. Without value. Should goes in the end of command
• -t transaction flag. Allow you to make income/expense transaction. Without value. Should goes in the end of command
• -j jwt flag. Should goes with your token (received via login)
• -m monetary flag. Should goes with Integer value (whether you want to add income/expense to your account)
• -i income flag. Define your transaction as income. Without value
• -e expense flag. Define your transaction as expense. Without value
• -b balance flag. Allow you to take a look at your balance. Without value. Should goes in the end of command
• -u url flag. if you need to define custom url in format: http://localhost:8010 (without slash in the end) with any other command

Architecture

Application Architecture implements Microservice choreography pattern and CQRS pattern

Application consist from 4 microservices:

• gateway - responsible for RestAPI and route queries to other services
• users - registration/login
• financial-transactions - keep financial transactions historically
• financial-balance - calculate balance, based on transactions and allow to retrieve it

To prevent additional AWS configuration, and be more atomic in running and vendor-free, following 3rd party (architecture) components was chosen

DB

PostgreSQL

Message Broker

RabbitMQ

Containerization

Docker (with docker-compose)

Known Technical Debt

• Way more code should be covered with unit and integration tests
• Service inside gateway should not notify different queues for making single transaction. Some sort of topic (when all consumers read single message) should be implemented
• for real clustering - docker compose can't be applicable as solution. Docker swarm or Kubernetes should be chosen instead
• Balance calculates asynchronously. Race condition might happen and balance might be inaccurate

Environments, was tested

Application was run only on MacOs. Should works fine under Linux

Authors

• Ihor Tsinko - email

License

This project is licensed under MIT License - all details in LICENSE.md file