Inside compose.yaml

Aisyah wrote the shop’s compose.yaml. It looks like a wall of words. Find the three dishes first.

Build the same file yourself. Add the three dishes. Give db its locker. Watch compose.yaml grow, block by block.

1services: {}

Each dish has a few keys. Sort them by what they do.

The locker is named twice: on the dish, and at the bottom. What if you delete the bottom block?

  db:
    image: postgres:18-alpine
    volumes:
      - db-data:/var/lib/postgresql

volumes:
  db-data:

~/kedai-kancil $ docker compose up -d[+] up 5/5 ✔ Network kedai-kancil_default Created                                     0.1s ✔ Volume kedai-kancil_db-data  Created                                     0.0s ✔ Container kedai-kancil-web-1 Started                                     0.3s ✔ Container kedai-kancil-api-1 Started                                     0.3s ✔ Container kedai-kancil-db-1  Started                                     0.3s~/kedai-kancil $ docker compose exec web wget -qO- http://api:3000{"ok":true,"shop":"Kedai Kancil"}

This file has no networks: block. Compose still made one phone line, kedai-kancil_default. Every dish calls another by its serviceservice: One dish in the set meal, like web or db. Compose makes its containers and names them after it. name, like api.

Dry run first. Ask Compose to print the final file, without starting anything.

You can now read every block of a compose.yaml.