🔄 Flask is a popular micro web framework written in Python.
🔄 Simplicity and Ease of Use: It has a gentle learning curve and is quick to get started with, even for beginners.
🔄 Great for APIs and Microservices
🔄 Flexibility & Lightweight
Perform +, −, ×, ÷ operations
Flask web interface
Docker and Docker Compose setup
Structure
flask-calculator/
├── app/
│ ├── __init__.py
│ ├── routes.py
│ ├── templates/
│ │ └── calculator.html
│ └── static/
│ └── style.css
├── requirements.txt
├── Dockerfile
├── docker-compose.yml
└── run.py
app/init.py
from flask import Flask
def create_app():
app = Flask(__name__)
from app.routes import main
app.register_blueprint(main)
return app
app/routes.py
from flask import Blueprint, render_template, request
main = Blueprint('main', __name__)
@main.route("/", methods=["GET", "POST"])
def calculator():
result = None
error = None
if request.method == "POST":
try:
num1 = float(request.form['num1'])
num2 = float(request.form['num2'])
operation = request.form['operation']
if operation == 'add':
result = num1 + num2
elif operation == 'subtract':
result = num1 - num2
elif operation == 'multiply':
result = num1 * num2
elif operation == 'divide':
if num2 != 0:
result = num1 / num2
else:
error = "Division by zero."
except ValueError:
error = "Invalid input."
return render_template("calculator.html", result=result, error=error)
app/templates/calculator.html
<!DOCTYPE html>
<html>
<head>
<title>Calculator</title>
</head>
<body>
<h1>Flask Calculator</h1>
<form method="post">
<input name="num1" placeholder="First number">
<input name="num2" placeholder="Second number">
<select name="operation">
<option value="add">+</option>
<option value="subtract">−</option>
<option value="multiply">×</option>
<option value="divide">÷</option>
</select>
<button type="submit">Calculate</button>
</form>
{% if result is not none %}
<p>Result: {{ result }}</p>
{% elif error %}
<p style="color:red">{{ error }}</p>
{% endif %}
</body>
</html>
run.py
from app import create_app
app = create_app()
if __name__ == "__main__":
app.run(debug=True, host="0.0.0.0")
requirements.txt
Flask==3.0.0
Dockerfile
FROM python:3.11-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
CMD ["python", "run.py"]
docker-compose.yml
version: '3.8'
services:
web:
build: .
ports:
- "5000:5000"
docker-compose build
docker-compose up