notes.md

1. Fork this repo into your GitHub Account and clone

Legacy application: How to Setup and Run (The "Painful" Way)

To demonstrate Factor 5 (Build/Release/Run) violations, you should perform these steps manually in front of the audience (or explain that you had to do them).

Step 1: Create a venv

. .venv/bin/activate

Step 2: Install Dependencies

pip install -r requirements_legacy.txt
# or
pip install Flask

Step 3: Manual Folder Creation (The Trap)

To run the application: python3 legacy-app.py In a 12-factor app, the app creates what it needs or uses external services. In this legacy app, if you run python legacy_app.py, it might fail or behave weirdly if permissions aren't right, or you have to "prep" the server. Failure: No logs, uploads, and counter directories.

Check the output in the browser

Violations

- 2: Dependencies not requirements.txt used
- 3: Hard coded secrets
- 4: The Database is coupled to the Application Code
- 5: manual and single build, run, release process
- 6: State is stored in files
- 7: Hard coded port
- 8: Unable spwan concurrent processes, the parallel app will be stand alone (have their own state)
- 9: It is not disposable as the state and logs are in the server itself
- 10: Depends on the provided environment
- 11: Logs in file
- 12: Need to SSH into the server, cannot configure anything from remote

In the Modern application

Step 1: Run the docker compose

docker compose up -d

Check the output in the browser

Step 2: Scaling

    docker-compose up -d --scale web=3 

Can be expanded to

• Docker volumes to store uploaded files so that if the container crashes the data is safe
• Can include ci/cd pipline for build/release/run
• Can also introduce any admin-process