How to Recreate This Project Step by Step

1. Create a new folder called coderco-challenge.

2. Inside that folder, create these files:

   • count.py – Flask app that talks to Redis
   • Dockerfile – builds the Python image
   • docker-compose.yml – defines the web and redis services
   • requirements.txt – lists Python dependencies

3. Install Docker Desktop and make sure the Docker engine is running.

4. Open the folder in VS Code.

5. Build and start everything with Docker Compose:

   docker compose up --build

6. Once both containers are running, open:

   • http://localhost:5002/ → welcome page
   • http://localhost:5002/count → visit counter backed by Redis

7. Stop and clean up the containers when you’re done:

   docker compose down -v

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Common Pitfalls (and How to Avoid Them)

1. Python indentation errors

   If a function in count.py isn’t indented correctly, the container will crash on start.

   • Tip: make sure each function body is indented with 4 spaces under the def line.

2. App file in the wrong place

   Docker needs to find count.py inside the same folder as the Dockerfile and docker-compose.yml.

   • Tip: confirm the structure looks like:

     coderco-challenge/
     ├─ count.py
     ├─ Dockerfile
     ├─ docker-compose.yml
     ├─ requirements.txt

3. Docker engine not running

   If docker compose up hangs or fails immediately, Docker Desktop might not be running.

   • Tip: open Docker Desktop first and check that it says “Engine running” before using the terminal.