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')
  project_id = json_key['project_id']
  [json_key['private_key'], json_key['client_email'], project_id]
end