docker plugin UX prototype

Proposal/Spec

Requirements

• Bash
• jq

Setup

• Put ./docker-plugin in your PATH
• Run docker-plugin to display usage

Differences from proposal

• Plugin containers are not hidden from docker ps
• All options of docker ps are available to docker-plugin ls
• Plugin containers are named in the format plugin.<image-basename>
• Overriding name without plugin. prefix will break docker-plugin ls
• No handshake performed, but _handshake env is set to "yes" or "no"
• During upgrade, docker pull failure is ignored to allow local images