FLASK-MULTI-TIER-APP

This guide explains the steps to set up a MySQL database inside a Docker container, create a table, insert sample data, and use a Flask application to access and display the data.

Step-by-Step Explanation

Step 1: Run a MySQL Docker Container

docker run -itd --name os1 -e MYSQL_ROOT_PASSWORD=redhat -e MYSQL_DATABASE=db -e MYSQL_USER=faizan -e MYSQL_PASSWORD=redhat mysql

• docker run: Run a new container.
• -itd: Start the container in interactive mode (-i), attach a terminal (-t), and run in detached mode (-d).
• --name os1: Assign the name os1 to the container.
• -e MYSQL_ROOT_PASSWORD=redhat: Set the root password for MySQL as redhat.
• -e MYSQL_DATABASE=db: Create a database named db inside MySQL.
• -e MYSQL_USER=faizan: Create a MySQL user named faizan.
• -e MYSQL_PASSWORD=redhat: Set the password for user faizan as redhat.
• mysql: Use the official MySQL image.

Step 2: Access the Container

docker exec -it os1 bash

• docker exec: Run a command inside a running container.
• -it os1 bash: Open an interactive bash shell in the os1 container.

Step 3: Access MySQL

mysql -u faizan -p redhat

• mysql: Launch the MySQL client.
• -u faizan: Log in as user faizan.
• -p redhat: Provide the password redhat for user faizan.

Step 4: Create a Table and Insert Data

show databases;
use db;
create table students (id int(5), name char(200), city char(10));
insert into students values (1, "faizan","pune");

• show databases;: List all available databases.
• use db;: Switch to the db database.
• create table students (...);: Create a table named students with columns id, name, and city.
• insert into students values (...);: Insert a row with values 1, "faizan", and "pune" into the students table.

Step 5: Exit the Container

exit

• Exit the MySQL client and the container shell.

Step 6 : Inspect Container for IP Address

docker inspect os1

• Retrieves the container details, including its IP address. This IP will be used in the Python application.

Step 7: Modify the Python Application

vim app.py

• Opens the app.py file in the Vim editor.
• Updates the IP address in the application to match the MySQL container's IP.

Step 8: Build a Flask Application Docker Image

docker build -t mypyos1 .

• docker build: Build a Docker image.
• -t mypyos1: Tag the image as mypyos1.
• .: Use the Dockerfile in the current directory to build the image.

Step 9: Run the Flask Application

docker run -it mypos1

• docker run: Start a container from the mypos1 image.
• -it: Run in interactive mode with a terminal attached.

Step 10: Access the Flask Application

Open a web browser and navigate to:

http://<container_ip>:5000/data

Replace <container_ip> with the IP address of the container.

This will display the data fetched from the students table in the MySQL database.

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Required Files

Dockerfile

Ensure the Dockerfile includes the necessary instructions to set up Flask and connect to the MySQL database.

Flask Application Code (app.py)

The Flask app should connect to the MySQL database and define a route /data to fetch and display the students table data.

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Example Output

When you access http://<container_ip>:5000/data, you should see:

[
    {
        "id": 1,
        "name": "faizan",
        "city": "pune"
    }
]