Docker Integration - RTFM First

When integrating a third-party Docker image (RAGFlow, Traefik, PostgreSQL, Redis, n8n, etc.), read the official configuration BEFORE writing any docker-compose line.

Why

Docker images are rarely self-contained. They often depend on:

• Configuration files mounted as volumes (nginx, traefik, etc.)
• Specific environment variables
• Init or entrypoint scripts
• Internal ports different from what you assume
• Service dependencies (healthchecks, startup order)

Never assume. Always verify.

Mandatory Checklist

Before writing a service in docker-compose.yml:

1. Read the Official docker-compose

# Find the project's official docker-compose.yml
# On GitHub: docker/, deploy/, or repo root

Identify:

• Mounted volumes: which config files are externalized?
• Exposed ports: what is the main entry port vs internal ports?
• Environment variables: which ones are required?
• Healthcheck: how does the service verify its health?
• Dependencies: depends_on with condition: service_healthy?
• Command/entrypoint: is the default CMD sufficient?

2. Inspect the Image if Needed

# View EXPOSE ports, CMD, ENTRYPOINT, volumes
docker inspect <image>:<tag>

# View running processes inside the container
docker exec <container> ps aux

# Check actually open ports
docker exec <container> bash -c 'for port in 80 443 8080 3000; do \
  (echo >/dev/tcp/localhost/$port) 2>/dev/null && echo "Port $port OPEN" \
  || echo "Port $port closed"; done'

3. Understand the Internal Architecture

Some images run multiple internal processes (e.g., RAGFlow = nginx + Python API + workers). Key questions:

• Which process serves the HTTP entry point?
• Is there an internal reverse proxy (nginx, caddy)?
• Is the documented port the proxy port or the application port?

Anti-Patterns

Anti-pattern	Consequence
Assuming the port without checking	Traefik routes to the wrong service (404)
Ignoring config volumes	Service starts with default config ("Welcome to nginx!")
Copying an example without reading	Missing files, undefined variables
Guessing memory limits	Silent OOM kills
Not reading the Dockerfile/entrypoint	Misunderstanding the internal architecture

Concrete Example: RAGFlow

The infiniflow/ragflow image requires 3 nginx files mounted as volumes:

volumes:
  - ./nginx/ragflow.conf:/etc/nginx/conf.d/ragflow.conf
  - ./nginx/proxy.conf:/etc/nginx/proxy.conf
  - ./nginx/nginx.conf:/etc/nginx/nginx.conf

Without them, nginx serves its default page instead of the RAGFlow UI. The entry port is 80 (nginx), not 9380 (internal Python API).