Docker support to wharf-cmd-worker

[applejag]

Inspired by RFC-0025: wharf-cmd provisioning

Depends on:

• Create component: wharf-cmd-worker #12

Requirements

• Ability to copy repository into new temporary directory, one copy per build step.

• Ability to generate build ID. Needs to not collide with previous build IDs via ~/.local/share/wharf/wharf-cmd/last-build-id.txt / %APPDATA%/wharf/wharf-cmd/last-build-id.txt file with simple file-based locking.

• Ability to create a new Docker container per build step containing:

  • Volume mounting copy of repository into container
  • labels:
    • app=wharf-cmd-worker-step
    • wharf.iver.com/managed-by=wharf-cmd
    • wharf.iver.com/instance=local
    • wharf.iver.com/build-ref=123
    • wharf.iver.com/project-id=456
    • wharf.iver.com/stage-id=789
    • wharf.iver.com/step-id=789

• Ability to list Docker containers for containers with labels:

  • wharf.iver.com/managed-by=wharf-cmd
  • wharf.iver.com/instance=local
  • wharf.iver.com/build-ref=*

• Ability to delete Docker containers based on their ID, and error if they don't have the following labels:

  • wharf.iver.com/managed-by=wharf-cmd
  • wharf.iver.com/instance=local
  • wharf.iver.com/build-ref=*

• All this by communicating via the Docker socket: https://docs.docker.com/engine/reference/commandline/dockerd/#bind-docker-to-another-hostport-or-a-unix-socket (and not by using the docker CLI)

  • unix:///var/run/docker.sock on Linux
  • tcp://127.0.0.1:2376 on Windows
  • or what's in the DOCKER_HOST environment variable

• Change step types to create Docker containers with the correct image and commands.

Out of scope (don't focus on this yet)

• Create a new Docker image with local repository to not need to duplicate repo files for each container. This is optimization that's left for later.