Is it possible to depend on either brew's docker or Docker for Mac?

[dserodio]

We have an internal tool that depends on Docker, and we created a formula for it. Currently, it depends_on "docker". I'd like to improve it to support either brew's docker package (/usr/local/opt/docker) or Docker for Mac (/usr/local/bin/docker -> /Applications/Docker.app/Contents/Resources/bin/docker). Is this possible?

Thanks in advance

[gromgit]

As far as I know, alternate dependencies are not supported, for the same reason brew install options in core formulae were removed: The CI cost to test all possible combinations gets ridiculous really fast.

If this is an internal-only formula, and you want brew to manage the dependencies for you, pick the formula or the cask and be done with it. If you absolutely positively must support both, then I suggest having your tool do the dependency management, e.g. check for /usr/local/bin/docker and prompt the user to choose which one to brew install if it's missing.

And if you plan to submit it to Homebrew core at some point, I'd stick with depends_on "docker".

[carlocab]

I think there was some old functionality that's now been removed (for homebrew-core, at least) related to depending on osxfuse or something that might help you here. I tried to track down the PRs where this was discussed, but couldn't find them. I distinctly remember it involved a user asking about how to do something similar with their own borgbackup formula that they maintain in their own tap.

[gromgit]

The end result of that is this: https://github.com/borgbackup/homebrew-tap/blob/master/Formula/borgbackup-fuse.rb

I guess it should be possible to write a custom Requirement that implements "alternate dependencies", though that won't be accepted on Homebrew core.

[carlocab]

Yes, that's the one. Thanks!

[dserodio]

Awesome, thanks! This internal tool is proprietary at the moment so we won't submit this formula to Homebrew core in the near future

[dserodio]

@nidr0x this would be a great improvement for cliditas' Homebrew formula when you have some spare time 😄