Meet the Product Catalog

The service you'll be hardening is a small Express REST API that returns a catalog of (very important) Docker merchandise. Let's get it running before you change anything, so you have a known-good baseline.

👀 Step 1: Explore the project

Take a look at the application entry point and the Dockerfile that builds it:

Open src/server.js — the API. Note it's hard-coded to port 3000.
Open Dockerfile — a single-stage build on node:22-slim, running as root.

cat Dockerfile

This is a typical starting point: a general-purpose base image, npm install, and a CMD. It works — but it isn't minimal and it isn't hardened.

🏗️ Step 2: Build the image

Build the catalog and tag it product-catalog:baseline so you can compare against it later.

docker build -t product-catalog:baseline .

🚀 Step 3: Run it

docker run -d --rm --name catalog -p 8090:3000 product-catalog:baseline

Note

The app listens on port 3000 inside the container, but the lab environment already uses some host ports (3000 and 8085) so you publish it on host port 8090 (-p 8090:3000) and reach it at localhost:8090. If 8090 is busy too, pick another free port (e.g. 9095) and use it consistently for the run command and URLs below.

Give it a second to boot, then check it's healthy:

curl -s http://localhost:8090/health

You should get back {"status":"ok",...}.

🛒 Step 4: Open the catalog

Open the running app in your browser at http://localhost:8090.

You can also hit the JSON API directly:

curl -s http://localhost:8090/products | head -c 400; echo

📏 Step 5: Note the baseline size

docker images product-catalog:baseline

Jot that number down — you'll watch it shrink dramatically once you adopt a Docker Hardened Image.

🧹 Step 6: Stop the container

docker stop catalog

The app works and you have a baseline. Now let's see what happens when a well-meaning change goes wrong. ➡️