module Google::Auth::JsonKeyReader

def read_json_key json_key_io
  json_key = MultiJson.load json_key_io.read
  raise "missing client_email" unless json_key.key? "client_email"
  raise "missing private_key" unless json_key.key? "private_key"
  [
    json_key["private_key"],
    json_key["client_email"],
    json_key["project_id"],
    json_key["quota_project_id"]
  ]
end