" Two-Tier Flask App Deployment with Docker"

🚀 Setting Up a Two-Tier Flask App on Docker 🚀

Before we dive into the exciting journey of setting up a two-tier Flask app using Docker, let's make sure you have everything you need. Follow these preliminary steps to ensure a smooth setup:

Prerequisites:

Basic Knowledge of Docker: Before we begin, make sure you have a basic understanding of Docker concepts. If you're new to Docker, consider going through the official documentation.
Docker Installed: Ensure Docker is installed on your machine. If not, you can follow the installation instructions on the official Docker website.
Git Installed: We'll be cloning a GitHub repository, so ensure Git is installed. If not, you can download and install Git from git.com.
Docker Hub Account: To push your custom Flask app image, you'll need a Docker Hub account. If you don't have one, sign up at hub.docker.com.

Now that we have the prerequisites covered, let's dive into the detailed steps of setting up our two-tier Flask app with Docker. Buckle up and let's get started!

👉 Note: If you already have the prerequisites in place, feel free to skip ahead to the main steps in the next section.

🔧 Install Docker:

COPY

COPY
```
  sudo apt update
  sudo apt install docker.io
```
This ensures that your system is updated and Docker is installed.
🐳 Check Docker Processes:

COPY

COPY
```
  docker ps
```
Verify that Docker is running and displaying any active containers.
🌀 Clone the Two-Tier Flask App Repository:

COPY

COPY
```
  git clone https://github.com/ganesh4400/two-tier-flask-app.git
  cd two-tier-flask-app/
```
Clone the Flask app repository and navigate to the project directory.

✏️ Edit Dockerfile:

COPY

  FROM python:3.9-slim

  WORKDIR /app

  RUN apt-get update -y \
          && apt-get upgrade -y \
          && apt-get install -y gcc default-libmysqlclient-dev pkg-config \
          && rm -rf /var/lib/apt/lists/*

  COPY requirements.txt .

  RUN pip install mysqlclient
  RUN pip install -r requirements.txt

  COPY . .

  CMD ["python","app.py"]

Create a Dockerfile to build the image for your Flask app, ensuring the necessary dependencies are installed.

🏗️ Build Docker Image:

COPY

COPY
```
  docker build . -t flaskapp
```
Build a Docker image for your Flask app based on the Dockerfile.
🖼️ List Docker Images:

COPY

COPY
```
  docker images
```
View the list of Docker images to ensure your 'flaskapp' image is successfully created.
🌐 Create Docker Network & Inspect Network:

COPY

COPY
```
  docker network create twotier
  docker network ls
  docker network inspect twotier
```
Create a Docker network for communication between containers.

🚢 Run MySQL Container:

COPY

  docker run -d -p 3306:3306 --network=twotier -e MYSQL_DATABASE=myDb -e MYSQL_USER=admin -e MYSQL_PASSWORD=admin -e MYSQL_ROOT_PASSWORD=admin --name=mysql mysql:5.7

Start a MySQL container with specified environment variables.

🚀 Run Flask App Container:

COPY

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

Launch the Flask app container with connections to the MySQL container.

🚦 Check Running Containers & Network between containers:

COPY

COPY
```
docker ps
docker network inspect twotier
```
Ensure both containers are running and connected in the 'twotier' network.
🔑 Login to Docker Hub:

COPY

COPY
```
docker login
# Enter your ID & Password
```
Log in to Docker Hub to push your custom Flask app image.
🏷️ Tag and Push Flask App Image to DockerHub:

COPY

COPY
```
docker tag flaskapp:latest dockerhubid/flaskapp:latest
docker images
docker push dockerhubid/flaskapp:latest
```
Tag your image and push it to your Docker Hub repository.
🛠️ Access Container Shell :

COPY

COPY
```
docker exec -it <container_id> bash
```
Access the shell of your container. We use this to access our database container to do below configurations.

Set Up Database and Table:

COPY

mysql -u root -p
# Enter your Password
use myDb;     # Select database
CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    message TEXT
);
#create tables in database

You can verify app is running by hitting below url in the browser

URL: server_ip:5000

📝 Install Docker Compose and Edit Docker Compose Configuration:

COPY

COPY
```
apt install docker-compose
vi docker-compose.yml
```
If you don't want to run two separate commands to run each containers we can use docker-compose to run both. Use a text editor to create or modify the Docker Compose configuration file.

📝 Edit Docker Compose Configuration:

COPY

version: '3'
services:
  backend:
    image: dockerhubid/flaskapp:latest
    ports:
      - "5000:5000"
    environment:
       MYSQL_HOST: "mysql"
       MYSQL_USER: "admin"
       MYSQL_PASSWORD: "admin"
       MYSQL_DB: "myDb"
    depends_on:
      - mysql
  mysql:
    image: mysql:5.7
    environment:
       MYSQL_DATABASE: "myDb"
       MYSQL_USER: "admin"
       MYSQL_PASSWORD: "admin"
       MYSQL_ROOT_PASSWORD: "admin"
    ports:
      - "3306:3306"
    volumes:
      - ./message.sql:/docker-entrypoint-initdb.d/message.sql
      - mysql-data:/var/lib/mysql
volumes:
  mysql-data:

Use this Docker Compose configuration to define both services (MySQL and Flask app) and their dependencies.

🚀 Launch Docker Compose:

COPY

COPY
```
docker-compose up -d
```
Start the Docker Compose services in detached mode. Docker Compose reads the configuration from docker-compose.yml and orchestrates the deployment.
🛑 Stop Docker Compose:

COPY

COPY
```
docker-compose down
```
Stop and remove the Docker Compose services.

Congratulations! You've successfully set up a two-tier Flask app on Docker with detailed steps for each stage. Feel free to explore, modify, and share your experiences with others in community. Happy coding! 🚀🐳

🚀 Connect with Me:

If you found this tutorial helpful or have any questions, feel free to connect with me on LinkedIn and GitHub. I'm always excited to engage with the developer community!

Edit this textLinkedIn 🌐
GitHub 🐱

Feel free to explore more of my projects and articles. Your feedback is valuable, and I'm here to assist you on your coding journey.