When trying to install snapcraft with snap install snapcraft --classic --edge I get the error error: cannot communicate with server: Post http://localhost/v2/snaps/snapcraft: dial unix /run/snapd.socket: connect: no such file or directory I can install it fine on my local computer.
snapd is not supported in docker, hence snapcraft cannot be directly installed. I am working on a docker container that includes snapcraft from each channel and will soon be pulished on docker hub for your convenience.
When do you think that will be done?
Here is a hack i wrote a while ago until @sergiusens has it ready in a proper way 
(See the README.md, there is an example using the snapcraft snap to build other snaps (hint: TMPDIR=. is mandatory for the moment))