Nubank

This is an interview exercise for Nubank

Pre-requisites

In order to execute this project you need to install:

Docker compose

Run project

Move into it
```
$ cd nubank
```
Build with docker
```
$ docker-compose build
```

Up all containers

$ docker-compose run nubank ruby main.rb < operations

Where operations is a file containing JSON lines with account/transactions info as follows:

{ "account": { "activeCard": true, "availableLimit": 10 } }
{ "transaction": { "merchant": "Burger King1", "amount": 2, "time": "2019-02-13T10:05:01.000Z" } }
{ "transaction": { "merchant": "Burger King2", "amount": 2, "time": "2019-02-13T10:05:02.000Z" } }
{ "transaction": { "merchant": "Burger King3", "amount": 2, "time": "2019-02-13T10:05:03.000Z" } }
{ "transaction": { "merchant": "Burger King4", "amount": 2, "time": "2019-02-13T10:05:04.000Z" } }

Run specs

   $ docker-compose run nubank bundle exec rspec

Design choices

- Docker, for portability and ease of deployment
- Ruby, it allows you to build things quickly and reliably
- Rspec, the de facto ruby test suite for integration and unit testing

Overall architecture

- main, the entrypoint that reads from STDIN
  - authorizer, the one on charge to keep track of the account and execute 
    each line of information
    - processors, each kind of entity is attended by a particular processor, 
      making it extensible
      - models, the detected entities in the business logic
      - validators, the business rules, each rule is attended by a particular 
        validator, making it extensible if new rules are coming
      - serializers, the responsibles to format the entities for the STDOUT

yovasx2 / nubank