Flask App with MySQL Docker Setup

This is a simple Flask application that interacts with a MySQL database. The app allows users to submit messages, which are then stored in the database and displayed on the frontend.

Prerequisites

Before you begin, make sure you have the following installed:

• Docker
• Git (optional, for cloning the repository)

Setup

1. Clone the Repository

Clone this repository to your local machine (if you haven't already)

git clone https://github.com/your-username/your-repo-name.git

Navigate to the project directory:

cd your-repo-name

2. Configure Environment Variables

Create a .env file in the project directory to store your MySQL environment variables:

touch .env

Open the .env file and add your MySQL configuration:

MYSQL_HOST=mysql
MYSQL_USER=your_username
MYSQL_PASSWORD=your_password
MYSQL_DB=your_database

3. Docker Compose Setup

Start the containers using Docker Compose:

docker-compose up --build

4. Access the Flask App

Once the containers are up and running, access the application in your web browser:

• Frontend: http://localhost
• Backend: http://localhost:5000

5. Create the Messages Table

Use a MySQL client or tool (e.g., phpMyAdmin) to execute the following SQL commands and create the messages table in your MySQL database:

CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    message TEXT
);

6. Interact with the App

1. Visit http://localhost to see the frontend where you can submit new messages using the form.
2. Visit http://localhost:5000/insert_sql to insert a message directly into the messages table via an SQL query.

Cleaning Up

To stop and remove the Docker containers, press Ctrl+C in the terminal where the containers are running, or use the following command:

docker-compose down

Run the Application Without Docker Compose

1. Build the Docker Image

First, create a Docker image from the Dockerfile:

docker build -t flaskapp .

2. Create Docker Network

Create a custom network for the containers to communicate with each other:

docker network create twotier

3. Run the Containers

i) MySQL Container

Run the MySQL container on the custom network:

docker run -d \
    --name mysql \
    -v mysql-data:/var/lib/mysql \
    --network=twotier \
    -e MYSQL_DATABASE=mydb \
    -e MYSQL_ROOT_PASSWORD=admin \
    -p 3306:3306 \
    mysql:5.7

ii) Backend (Flask) Container

Run the Flask backend container, linking it to the same network:

docker run -d \
    --name flaskapp \
    --network=twotier \
    -e MYSQL_HOST=mysql \
    -e MYSQL_USER=root \
    -e MYSQL_PASSWORD=admin \
    -e MYSQL_DB=mydb \
    -p 5000:5000 \
    flaskapp:latest

Notes

• Make sure to replace the placeholders (your_username, your_password, your_database) with your actual MySQL configuration in the .env file.
• This setup is a basic demonstration. For production environments, follow best practices for security and performance.
• Be cautious when executing SQL queries directly. Validate and sanitize user inputs to prevent vulnerabilities like SQL injection.
• If you encounter issues, check Docker logs and error messages for troubleshooting.

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