varshithchand/flask-backend repository overview

🚀 Flask PostgreSQL Docker Setup

This repository provides a production-ready Flask backend application running with Gunicorn and connected to PostgreSQL using Docker networking.

It is designed for clean deployment, easy scalability, and DevOps-friendly workflows.

---

🐳 1. Pull Required Images

docker pull postgres:15
docker pull varshithchand/flask-app

---

🌐 2. Create Docker Network

docker network create mynetwork

---

🗄️ 3. Run PostgreSQL Container

docker run -d --name postgres_db
--network mynetwork
-e POSTGRES_USER=postgres
-e POSTGRES_PASSWORD=password
-e POSTGRES_DB=mydb
-p 5432:5432 postgres:15

---

🚀 4. Run Flask Application (Gunicorn)

docker run -d --name flask_app
--network mynetwork
-p 5000:5000 varshithchand/flask-app

---

🌐 5. Access Application

http://localhost:5000⁠

---

📡 API Endpoints

GET /users
→ Fetch all users

POST /users
→ Add new user

DELETE /users/
→ Delete user

---

⚙️ Database Configuration (IMPORTANT)

Your Flask app uses:

postgresql://postgres:password@postgres_db:5432/mydb

✔ postgres_db → container name
✔ same Docker network required

---

🧠 How It Works

• PostgreSQL runs in postgres_db container
• Flask runs in flask_app container using Gunicorn
• Both containers communicate via mynetwork
• Flask connects using container hostname (NOT localhost)

---

🛑 Stop & Remove Containers

docker stop flask_app postgres_db
docker rm flask_app postgres_db

---

🔥 Full Reset (Clean Setup)

docker rm -f flask_app postgres_db
docker volume prune -f
docker network rm mynetwork

---

⚠️ Common Issues & Fixes

❌ Container exits immediately
👉 Check logs:
docker logs flask_app

❌ Database connection error
✔ Ensure:

• Correct hostname → postgres_db
• Same network → mynetwork

❌ Port already in use
👉 Use different port:
docker run -d -p 5001:5000 ...

---

🚀 Recommended Next Step

Use Docker Compose for better setup:

docker-compose up --build

✔ Auto networking
✔ Dependency handling
✔ Cleaner workflow

---

👨‍💻 Author
Varshith Chand
Aspiring DevOps Engineer 🚀give an option to copy paste the commands