Could we expose a better interface than a list of constants? Why does the code need to know about this?

@dnephin Hmmm... The reason the code is here is that you can build from any valid Docker remote location, https://docs.docker.com/reference/api/docker_remote_api_v1.20/#build-image-from-a-dockerfile

Looking at the Docker compose docs doesn't seem like this is possible. Is there a specific reason you aren't allowed to do a Docker build from a remote location? By remote I mean the definition of the remote param on POST /build

No reason, there's an PR to add that support (that needs more work), but I don't know if anyone is actively working on it.

There's been very little demand for it, so it hasn't been a priority.

Sorry, my earlier question was, why does code external to libcompose need this constant

@dnephin The reason why is that you can supply a custom Builder. So currently we use libcompose in a server side context. In that context we don't want to allow builds that reference the disk. So we only allow remote builds if libcompose is ran in a server side context.

@ibuildthecloud Using it on rancher-compose right ?

I'm wondering something though, should it be there (in libcompose) or in docker/docker ? I would think in docker/docker in a non-internal package (like the api one that should be there at some point or in a pkg — but I'm not that sure about pkg).

In docker/docker would be preferred and that is where I copied the list to begin with. Let me look from where. I imagine it was private.

@ibuildthecloud @dnephin I think we should fill an issue for make this better and merge this one as it breaks current codes, wdyt ? (the actual list feels weird at it would mean git@github.com:vdemeester/libcompose is a valid git+ssh remote but vincent@myhost:src/docker/libcompose would not 😓 — but that's outside the scope of this PR).

@ibuildthecloud isn't it in pkg/urlutil (https://github.com/docker/docker/blob/master/pkg/urlutil/urlutil.go#L11) ?

Ya, I'm ok merging this, it shouldn't hurt anything

Created #95, so LGTM 🐺