Policies for docker

[sadams-evi]

Can I craft policies for docker images ?
I would like to implement the following policy in regula.
Is it possible for me to write a similar policy using regula, or will I need to build my own user libraries to implement this policy ?

package builtin.dockerfile.DS002

import data.lib.docker

# get_user returns all the usernames from
# the USER command.
get_user[username] {
	user := docker.user[_]
	username := user.Value[_]
}

# fail_user_count is true if there is no USER command.
fail_user_count {
	count(get_user) < 1
}

# fail_last_user_root is true if the last USER command
# value is "root"
fail_last_user_root[lastUser] {
	users := [user | user := docker.user[_]; true]
	lastUser := users[count(users) - 1]
	lastUser.Value[0] == "root"
}

deny[res] {
	fail_user_count
	msg := "Specify at least 1 USER command in Dockerfile with non-root user as argument"
	res := result.new(msg, {})
}

deny[res] {
	cmd := fail_last_user_root[_]
	msg := "Last USER command in Dockerfile should not be 'root'"
	res := result.new(msg, cmd)
}