Please document build_args_from_env

[yutannihilation]

After struggling to use a secret as build-time envvar, I found undocumented parameter build_args_from_env. This seems very helpful. Can you add a brief description here?

http://plugins.drone.io/drone-plugins/drone-docker/

(I'm happy to create a PR for this, but I don't find the source of the doc...)

[vaddenz]

+1 too!

And for those who don't know how to use:

steps:
  - name: build-image
    image: plugins/docker
    environment:
      TOKEN:
        from_secret: one_of_the_tokens
    settings:
      build_args_from_env:
        - TOKEN

or have a look at PR 140

[tboerger]

Please provide a PR to https://github.com/drone/drone-plugin-index/blob/master/content/drone-plugins/drone-docker/index.md for adding information about it.

[yutannihilation]

Thanks, will do!

[yutannihilation]

@Leboudin Thanks for the nice example! Can I use it in my PR?

[vaddenz]

@Leboudin Thanks for the nice example! Can I use it in my PR?

Sure!

[yutannihilation]

Thanks 👍