Bank Application

API de saque e transferência

Install Dependencies

pip install -r requirements.txt

For more information on pip requirements, files check the documentation

Database

Model

Setup

# Create a migration repository
flask db init

# Generate migration
flask db migrate

# Apply migration
flask db upgrade

For manually creating a customer:

from app import db
from app.models import Customer, Transaction

# Create Customer 1
c1 = Customer(name="Alexandre", account="12345", cpf="12345678900")
db.session.add(c1)
db.session.commit()

# Add funds to play with transactions and withdraw
transaction = Transaction(
    type="Deposit",
    to_customer_id=c1.id,
    amount=100000,
  )

db.session.add(transaction)
db.session.commit()

# Create Customer 2
c2 = Customer(name="Tester", account="12344", cpf="12345678901")
db.session.add(c2)
db.session.commit()

Run app

# Create the virtual environment
python3 -m venv venv

# Install Dependencies
pip install -r requirements.txt

# Run Flask
flask run

Manual testing the app

Balance

curl "http://127.0.0.1:5000/balance/1"

Withdraw

curl -X "POST" "http://127.0.0.1:5000/withdraw" \
     -H 'Content-Type: application/json; charset=utf-8' \
     -d $'{
  "from_customer_id": "1"
  "amount": "100",
}'

Transfer

curl -X "POST" "http://127.0.0.1:5000/transfer" \
     -H 'Content-Type: application/json; charset=utf-8' \
     -d $'{
  "from_customer_id": "1"
  "to_customer_id": "2",
  "amount": "100",
}'

Future implementations

• Customer authentication. You can currently POST to the API and add any transactions without validating that you are the customer creating the transaction.
• Improve Customer model with more required data
• Migrate from SQLite to PostgreSQL
• Migrate to Cloud Provider

Proposed Serverless Architecture

This is an oversimplification of the architecture:

• Use Route53 to define the DNS.
• API Gateway to create the internet accessible API endpoints or create a VPC for internal use
• Lambdas to run the Flask API
• Amazon RDS to store the transactions
• Amazon Cognito to store user credentials and provide authentication
• AWS CloudTrail for audit and compliance
• We would also use AWS CloudWatch for logs

Documentation

• Flask
• Flask-SQLAlchemy
• SQLAlchemy Migrate