Allow URL in `services[].build.dockerfile` too

[victorstanciu]

Description

services[].build accepts a URL to a remote Dockerfile since #2430. It would be great if services.build[].dockerfile worked the same way, so that other subkeys of build could be specified (like args).

[ndeloof]

URL support applies to context attribute, not to the dockerfile one, which is defined as a path relative to the context root:

services:
  demo:
    build:
      context: github.com/docker/compose

I'm closing this issue as "already implemented"

[victorstanciu]

@ndeloof thank you for checking into this so quickly, but are you sure that's the case? I can pass in a URL to the build parameter and Compose fetches the Dockerfile for me:

This is the Compose file I used:

version: '3.7'
services:
    nginx:
        build: https://raw.githubusercontent.com/nginxinc/docker-nginx/master/mainline/alpine/Dockerfile

[ndeloof]

build: <path> is just a short notation for

build:
   context: <path>

[victorstanciu]

@ndeloof Got it now, thanks a lot!