Method fetched

src/master/detector/zookeeper.cpp:189–266

void ZooKeeperMasterDetectorProcess::fetched(
    const Group::Membership& membership,
    const Future<Option<string>>& data)
{
  CHECK(!data.isDiscarded());

  if (data.isFailed()) {
    leader = None();
    failPromises(&promises, data.failure());
    return;
  } else if (data->isNone()) {
    // Membership is gone before we can read its data.
    leader = None();
    setPromises(&promises, leader);
    return;
  }

  // Parse the data based on the membership label and cache the
  // leader for subsequent requests.
  Option<string> label = membership.label();
  if (label.isNone()) {
    // If we are here it means some masters are still creating znodes
    // with the old format.
    UPID pid = UPID(data->get());
    LOG(WARNING) << "Leading master " << pid << " has data in old format";
    leader = mesos::internal::protobuf::createMasterInfo(pid);
  } else if (label.isSome() &&
             label.get() == internal::master::MASTER_INFO_LABEL) {
    MasterInfo info;
    if (!info.ParseFromString(data->get())) {
      leader = None();
      failPromises(&promises,
          "Failed to parse data into MasterInfo");
      return;
    }
    LOG(WARNING) << "Leading master " << info.pid()
                 << " is using a Protobuf binary format when registering with "
                 << "ZooKeeper (" << label.get() << "): this will be deprecated"
                 << " as of Mesos 0.24 (see MESOS-2340)";
    leader = info;
  } else if (label.isSome() &&
             label.get() == internal::master::MASTER_INFO_JSON_LABEL) {
    Try<JSON::Object> object = JSON::parse<JSON::Object>(data->get());

    if (object.isError()) {
      leader = None();
      failPromises(
          &promises,
          "Failed to parse data into valid JSON: " + object.error());
      return;
    }

    Try<mesos::MasterInfo> info =
      ::protobuf::parse<mesos::MasterInfo>(object.get());

    if (info.isError()) {
      leader = None();
      failPromises(