vboxapi.go provides a simple rest api that mimicks the Node.js project vboxmanage-rest-api for only the bits Kraken needs.
$ vboxapi -h
Usage of vboxapi:
-base string
base URL for api (default "/vboxmanage")
-ip string
ip to listen on (default "127.0.0.1")
-port uint
port to listen on (default 8269)
-v verbose messages
-vbm string
full path to vboxmanage command (default "/usr/local/bin/vboxmanage")