🚀 Flask + PostgreSQL + Docker CRUD REST API

A simple CRUD REST API built using Flask and PostgreSQL, containerized using Docker.
This project demonstrates building, running, and testing backend APIs with database integration.

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📂 Project Structure

flask-postgres-crud/
├── Dockerfile # Dockerfile to containerize the Flask app
├── app.py # Main Flask application
├── database/ # PostgreSQL database setup scripts
|     └── Dockerfile  # Dockerfile to the containerizeto postgresql
├── requirements.txt # Python dependencies
├── venv/ # Python virtual environment
└── README.md

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⚡ Features

• Create, Read, Update, Delete (CRUD) operations
• RESTful API design
• PostgreSQL database integration
• Docker containerized (easy deployment)

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🛠 Tech Stack

• Backend: Python 3.11, Flask 2.3.2
• Database: PostgreSQL 15
• Containerization: Docker

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📦 Setup & Run

Clone Repo

git clone https://github.com/samarthgarde/Flask-Postgres-CRUD-API.git
cd Flask-Postgres-CRUD-API

Virtual environment set and activate it

python3 -m venv venv
source venv/bin/activate

Create network

docker network create mynetwork

Create volume

docker volume create pgdata

Build & Run my-webapp container

docker build -t flask-app .
docker run -d --name my-python-container --network mynetwork -e DATABASE_URL=postgresql://postgres:postgres@my_postgres:5432/cruddb -p 5000:5000 flask-app

Build & Run postgres:15 container

cd database/
docker build -t postgres:15 .
docker run -d --name my_postgres --network mynetwork -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=password -e POSTGRES_DB=cruddb -v pgdata:/var/lib/postgresql/data -p 5432:5432 postgres:15

Check live logs

docker logs my-postgres -f
docker logs my-python-container -f

Network Check

docker network ls
docker network inspect mynetwork

Environment Variable Check (DATABASE_URL)

docker exec -it my-python-container env | grep DATABASE_URL

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Test APIs using Postman / Curl / Browser (for GET requests)

Test "Get all students" (GET)

• URL:http://localhost:5001/students
• Method: GET

curl http://localhost:5001/students

Test "Add student" (POST)

• URL: http://localhost:5001/students
• Method: POST
• Body (JSON):

{
  "firstname": "samarth",
  "lastname": "garde",
  "birthdate": "2000-01-01",
  "email": "samarthgarde@example.com",
  "enrolled_date": "2025-09-30"
}

• Using curl:

curl -X POST http://localhost:5001/students \
-H "Content-Type: application/json" \
-d '{"firstname":"samarth",garde":"Doe","birthdate":"2000-01-01","email":"samarthgarde@example.com","enrolled_date":"2025-09-30"}'

Test "Get single student" (GET)

• URL: http://localhost:5001/students/1
• Method: GET

curl http://localhost:5001/students/1

Test "Add item" (POST)

• URL: http://localhost:5001/items
• Body (JSON):

{
  "name": "Book",
  "description": "Python Programming Book"
}

• usage with curl:

curl -X POST http://localhost:5001/items \
-H "Content-Type: application/json" \
-d '{"name":"Laptop","description":"Gaming laptop"}'

• Get all items

curl http://localhost:5001/items/1

• Update an item

{"id":1,"name":"Laptop Pro","description":"High-end gaming laptop"}

• Delete an item

curl -X DELETE http://localhost:5001/items/1

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Using psql in terminal (Postgres CLI)

Step 1: Access Postgres container

docker exec -it my_postgres psql -U postgres -d cruddb

Step 2: Show tables

\dt

Step 3: Select data in a table format

SELECT * FROM students;
SELECT * FROM items;

step 4: To exit psql

\q

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Using a GUI tool

• pgAdmin (official, free)

• Steps:

• 1.Add a new server

• Right-click Servers → Create → Server…

• General tab:

• Name: MyDockerPostgres (any name)

• Connection tab:

• Host name/address: localhost

• Port: 5432

• Username: postgres

• Password: postgres

• Save Password: check the box

• Click Save.

• Verify connection

• Expand Servers → MyDockerPostgres → Databases → cruddb→ Schemas → public → Tables

• You should see your tables: students and items.

View data in table format

• Right-click table (e.g., students) → View/Edit Data → All Rows
• pgAdmin shows data in a spreadsheet-like format.
• You can edit, delete, or insert rows directly in pgAdmin.
• Also, you can run custom SQL queries in Query Tool (Tools → Query Tool)

SELECT * FROM students;
SELECT * FROM items;

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🎯 Objective

This project is intended to:

• Teach Flask + PostgreSQL integration
• Demonstrate CRUD operations with REST API
• Provide practical Docker containerization experience

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👨‍💻 Author

Made with ❤️ Samarth Garde