Helm in Practice

mkdir -p $HOME/todowithdb-app/app

cat << 'EOF' > $HOME/todowithdb-app/app/app.py
import os
from flask import Flask, jsonify, request
import psycopg2
from psycopg2.extras import RealDictCursor

app = Flask(__name__)

# Database configuration from environment variables
# These will be injected by Kubernetes from our Helm values
DB_HOST = os.environ.get("DB_HOST", "localhost")
DB_PORT = int(os.environ.get("DB_PORT", "5432"))
DB_NAME = os.environ.get("DB_NAME", "todo_db")
DB_USER = os.environ.get("DB_USER", "todo_user")
DB_PASSWORD = os.environ.get("DB_PASSWORD", "todo_password")


def get_db_connection():
    """
    Create a new PostgreSQL connection.
    In production, you might use a connection pool or PgBouncer,
    but this simple approach works well for learning.
    """
    conn = psycopg2.connect(
        host=DB_HOST,
        port=DB_PORT,
        dbname=DB_NAME,
        user=DB_USER,
        password=DB_PASSWORD,
    )
    return conn


def init_db():
    """
    Initialize the database schema.
    Creates the tasks table if it doesn't exist.
    In production, use a migration tool like Alembic.
    """
    conn = get_db_connection()
    try:
        with conn.cursor() as cursor:
            cursor.execute(
                """
                CREATE TABLE IF NOT EXISTS tasks (
                    id SERIAL PRIMARY KEY,
                    title TEXT NOT NULL,
                    description TEXT NOT NULL
                );
                """
            )
        conn.commit()
    finally:
        conn.close()


@app.route("/health", methods=["GET"])
def health_check():
    """Simple health check endpoint for Kubernetes probes."""
    return jsonify({"status": "healthy"})


@app.route("/tasks", methods=["GET"])
def get_tasks():
    """Return all tasks as JSON."""
    conn