Compose

Table of contents

1. File Format
2. What The Parser Enforces
3. Current Runtime Semantics
4. Commands
5. Ordering

---

Jerboa compose is a small, project-local stack format implemented in internal/compose/.

File Format

version: "1"

services:
  api:
    image: api:latest
    memory: 256M
    cpus: 1
    depends_on: [db]
    networks: [app]
    ip: 10.100.0.10
    environment:
      - PORT=8080
    ports:
      - "8080:8080"
    volumes:
      - data:/var/data
    health_check: "http:8080:/healthz"
    restart: "on-failure:5"

networks:
  app:
    driver: bridge
    subnet: 10.100.0.0/24

volumes:
  data:
    size: 1G

What The Parser Enforces

• version, if present, must be "1"
• at least one service is required
• every service must define image
• depends_on targets must exist
• referenced networks must exist in the top-level networks map
• referenced named volumes must exist in the top-level volumes map

Current Runtime Semantics

• only the first network in networks: is actually wired to a service instance
• services reach each other by service name over the daemon’s guest DNS (e.g. a web service connects to db:5432); see Service Discovery
• ip: pins a service to a static address on its network; without it the daemon’s IPAM allocates one. Name resolution works either way, so ip: is only needed when a fixed address is required
• top-level volumes are auto-created during compose up
• top-level networks are auto-created during compose up
• compose down --volumes removes only volumes created by that stack
• stacks are tracked by a local state file named .jerboa-compose-state.json next to the compose file

Commands

jerboa compose up stack.yaml
jerboa compose ps stack.yaml
jerboa compose logs stack.yaml api
jerboa compose down stack.yaml --volumes

Current limits:

• compose logs is snapshot-only
• there is no compose logs -f

Ordering

Startup order is computed with topological sort from depends_on.

Shutdown order is the reverse of the recorded startup ordering.