in lib/omnibus/build_system_metadata/buildkite.rb [116:126]
def to_hash
ret = {}
ret[:ami_id] = ami_id if ami_id != "unknown"
ret[:hostname] = hostname if hostname != "unknown"
ret[:is_docker_build] = is_docker_build if is_docker_build
ret[:docker_version] = docker_version if docker_version
ret[:docker_image] = docker_image if docker_image
ret[:omnibus_version] = omnibus_version
ret
end