Repo2docker: support .binder instead of binder as config directory

[rabernat]

I would like to use the path.binder/ rather than binder/ for my repo configuration. I read the docs but couldn't figure out if it is supported to change the config path. I tried it and I think it did not work.

[betatim]

Currently not supported.

[choldgraf]

hey @rabernat - could you explain more why you want to use .binder instead of binder/?

[jhamman]

I'm +1 on a change like this. It would be nice to have the option to "hide" the binder directory from the user. I think this is less of an issue for the Binder use case but for uses of repo2docker outside of Binder, the binder directory can be distracting. I think the use case @rabernat and I are are both thinking of is when we use repo2docker to build custom images for our JupyterHub deployments.

[betatim]

I think supporting both .binder and binder could be interesting and worth exploring with a PR.

What kind of feedback do you get from users when they are confused/distracted by this? One good thing about it being explicit is that it makes it (more) obvious how the environment was crafted and how to recreate it yourself at home.

[choldgraf]

it sounds like @jhamman is imagining this in the context of jupyterhub rather than binderhub (e.g. using a github repo to define the environment + files, but not necessarily in the context of a reproducible analysis etc)

[betatim]

One solution to "my users are confused" is to add a postBuild line that does rm -rf binder/ to remove all traces of how the repo was created :) You could also add that to an appendix for your repo2docker run so that you don't have to put it in each repo.

[consideRatio]

It is very typical, for example .circleci etc, that build configuration stuff is in hidden files and folders. Since it has been done with the nonhidden binder folder up until now, i also think a pr to support both would make sense.

[choldgraf]

I'm +1 on supporting a hidden folder called .binder

[jhamman]

I've opened PR #653 to add support for the .binder directory.