Method registerSlave

src/master/master.cpp:6217–6294

void Master::registerSlave(
    const UPID& from,
    RegisterSlaveMessage&& registerSlaveMessage)
{
  ++metrics->messages_register_slave;

  if (authenticating.contains(from)) {
    LOG(INFO) << "Queuing up registration request from " << from
              << " because authentication is still in progress";

    authenticating[from]
      .onReady(defer(self(),
                     &Self::registerSlave,
                     from,
                     std::move(registerSlaveMessage)));
    return;
  }

  if (flags.authenticate_agents && !authenticated.contains(from)) {
    // This could happen if another authentication request came
    // through before we are here or if a slave tried to register
    // without authentication.
    LOG(WARNING) << "Refusing registration of agent at " << from
                 << " because it is not authenticated";
    return;
  }

  Option<Error> error =
    validation::master::message::registerSlave(registerSlaveMessage);

  if (error.isSome()) {
    LOG(WARNING) << "Dropping registration of agent at " << from
                 << " because it sent an invalid registration: "
                 << error->message;

    return;
  }

  if (slaves.registering.contains(from)) {
    LOG(INFO) << "Ignoring register agent message from " << from
              << " (" << registerSlaveMessage.slave().hostname()
              << ") as registration is already in progress";

    return;
  }

  LOG(INFO) << "Received register agent message from " << from
            << " (" << registerSlaveMessage.slave().hostname() << ")";

  slaves.registering.insert(from);

  // Update all resources passed by the agent to `POST_RESERVATION_REFINEMENT`
  // format. We do this as early as possible so that we only use a single
  // format inside master, and downgrade again if necessary when they leave the
  // master (e.g. when writing to the registry).
  upgradeResources(&registerSlaveMessage);

  // Note that the principal may be empty if authentication is not