Flask App with MySQL Docker Setup

This is a simple Flask app 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

Clone this repository (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
```
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

Usage

Start the containers using Docker Compose:
```
docker-compose up --build
```
Access the Flask app in your web browser:
- Frontend: http://localhost
- Backend: http://localhost:5000
Create the messages table in your MySQL database:
- Use a MySQL client or tool (e.g., phpMyAdmin) to execute the following SQL commands:
```
CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    message TEXT
);
```
Interact with the app:
- Visit http://localhost to see the frontend. You can submit new messages using the form.
- 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

To run this two-tier application using without docker-compose

First create a docker image from Dockerfile

docker build -t flaskapp .

Now, make sure that you have created a network using following command

docker network create twotier

Attach both the containers in the same network, so that they can communicate with each other

i) MySQL container

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 container

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 placeholders (e.g., your_username, your_password, your_database) with your actual MySQL configuration.
This is a basic setup for demonstration purposes. In a production environment, you should 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.