Invalid service name. Valid characters are [a-zA-Z0-9]

[pdehaan]

Steps to reproduce:

Try and validate the following YAML business:

db:
    image: postgres:9.3

frontend_watcher:
    extends:
        file: docker-compose-base.yml
        service: frontend-watcher

server:
    extends:
        file: docker-compose-base.yml
        service: server
    links:
        - db
        - frontend_watcher

Actual results:

"Invalid service name. Valid characters are [a-zA-Z0-9]"

Expected results:

It should probably allow hyphens and underscores. I haven't been able to find an official spec on container naming yet, but this is the closest I've gotten:

docker/compose ./compose/config/validation.py:40:

VALID_NAME_CHARS = '[a-zA-Z0-9\._\-]'

[pdehaan]

Actually, this is probably a dupe of CenturyLinkLabs/lorry#45 and this is an API issue.