Support for Docker Unix socket.

[pviotti]

Hello!

It appears that the support for connections to the Docker Unix socket (which is the default socket in plain Docker installs) is not implemented.
Specifically, it crashes on nkdocker_app:start() when trying to read the DOCKER_HOST variable ( nkdocker_app.erl ) if it's something different from tcp://....

I was wondering: why is this not supported? Would it be difficult to add support for it?

Thanks in advance!

[pviotti]

Uh, I see: Erlang does not have a built-in support for Unix sockets...
This other project used an external tool to make up for this lack.
In any case, that would be a nice feature to have.

[kalta]

The socat solution is not very elegant but easy. I will probably add it.