How to generate a graph from compose.yaml

Imagine you have a very big compose.yaml file with a lot of services and dependencies.

You also have multiple exposed ports.

You'd like to have an at-a-glance view of services, dependencies and open ports. Is this possible? Yes! https://github.com/compose-viz/compose-viz does the magic for us.

Here's what compose-viz generates from a Joomla compose.yaml:

Reproduce it yourself​

For the demo, please start a Linux shell and run mkdir -p /tmp/compose-viz && cd $_ to create a folder called compose-viz in your Linux temporary folder and jump in it.

Please create a new file called compose.yaml with this simplified content:

services:
  joomla:
    image: joomla
    ports:
      - 8080:80?
    depends_on:?
      - joomladb

  joomladb:
    image: postgres:16.0-alpine?

Let the magic happen and run docker run --rm -it -u $(id -u):$(id -g) -v $(pwd):/in wst24365888/compose-viz compose.yaml — you'll get the image shown above.

A more complex example​

Replace the content of the compose.yaml with this one:

services:

  redis:
    image: redis:alpine
    ports:
      - "6379"?
    networks:
      - frontend
    deploy:
      replicas: 2?
      update_config:
        parallelism: 2?
        delay: 10s
      restart_policy:
        condition: on-failure

  db:
    image: postgres:9.4
    volumes:
      - db-data:/var/lib/postgresql/data?
    networks:
      - backend
    deploy:
      placement:
        constraints: [ node.role == manager ]?
  vote:
    image: dockersamples/examplevotingapp_vote:before
    ports:
      - 5000:80?
    networks:
      - frontend
    depends_on:?
      - redis
    deploy:
      replicas: 2
      update_config:
        parallelism: 2
      restart_policy:
        condition: on-failure
  result:
    image: dockersamples/examplevotingapp_result:before
    ports:
      - 5001:80
    networks:
      - backend
    depends_on:
      - db
    deploy:
      replicas: 1
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure

  worker:
    image: dockersamples/examplevotingapp_worker
    networks:
      - frontend
      - backend
    deploy:
      mode: replicated?
      replicas: 1
      labels: [ APP=VOTING ]?
      restart_policy:
        condition: on-failure
        delay: 10s?
        max_attempts: 3?
        window: 120s?
      placement:
        constraints: [ node.role == manager ]

  visualizer:
    image: dockersamples/visualizer
    ports:
      - "8080:8080"
    stop_grace_period: 1m30s?
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock?
    deploy:
      placement:
        constraints: [ node.role == manager ]

networks:
  frontend:
  backend:

volumes:
  db-data:

And the image here below will be generated by the tool:

Here, we can see:

• We've four exposed ports: 5001, 5000, 6379 and 8080.
• Port 8080 is linked to a visualizer web service; that service is using a volume pointing to /var/run/docker.sock
• Ports 5000 and 5001 are referring to services called vote and result. Since the internal port is port 80, we know that these ports are web interfaces.
• The vote service (port 5000) is using a redis service; accessible using port 6379.
• The result service (port 5001) is linked to a Postgres service called db and having persistent data (since we have a Docker volume called db-data).
• And so on.

Such a visualization tool greatly simplifies the understanding of a Docker architecture.

compose-viz gives you one fixed rendering. If you want to control exactly what the diagram shows, Documentation as Code - Transform Your Infrastructure into Beautiful Diagrams with Python and Mermaid parses the same compose.yaml with a Python script you own, and Docker - Diagrams as code lists a dozen other diagram-as-code tools.

Docker config​

If like me you're using a lot of .yml files by running Docker and/or using environment variables in it; just run docker compose config to ask Docker to render (on the screen only) what it calls Parse, resolve and render compose file in canonical format i.e. it will merge all your .yml in one string and resolve variables.

Copy/paste the screen output in a temporary file and use this tool on that file.