Keep Secrets and Junk out of the Build Context

Labs have no container engine, so nothing is built or started: your files are checked by reading them, the way a reviewer or a CI linter would. docker-compose config (to validate Compose files) and hadolint (a Dockerfile linter) are installed.

Building /home/student/projects/chat-relay sends 1.2 GB to the builder, and the image was found to contain the .env file with production secrets.

Task

Create /home/student/projects/chat-relay/.dockerignore so that the build context excludes:

• the .git folder and node_modules (wherever it is)
• every .env file and every *.pem key, in any folder, except .env.example
• every *.log file in any folder, and the coverage/ folder

and still includes everything else: the source, package.json, package-lock.json, Dockerfile and .env.example.