Method authenticate

src/slave/slave.cpp:1544–1608

void Slave::authenticate(Duration minTimeout, Duration maxTimeout)
{
  authenticated = false;

  if (master.isNone()) {
    return;
  }

  if (authenticating.isSome()) {
    // Authentication is in progress. Try to cancel it.
    // Note that it is possible that 'authenticating' is ready
    // and the dispatch to '_authenticate' is enqueued when we
    // are here, making the 'discard' here a no-op. This is ok
    // because we set 'reauthenticate' here which enforces a retry
    // in '_authenticate'.
    Future<bool> authenticating_ = authenticating.get();
    authenticating_.discard();
    reauthenticate = true;
    return;
  }

  LOG(INFO) << "Authenticating with master " << master.get();

  // Ensure there is a link to the master before we start
  // communicating with it.
  link(master.get());

  CHECK(authenticatee == nullptr);

  if (authenticateeName == DEFAULT_AUTHENTICATEE) {
    LOG(INFO) << "Using default CRAM-MD5 authenticatee";
    authenticatee = new cram_md5::CRAMMD5Authenticatee();
  }

  if (authenticatee == nullptr) {
    Try<Authenticatee*> module =
      modules::ModuleManager::create<Authenticatee>(authenticateeName);
    if (module.isError()) {
      EXIT(EXIT_FAILURE)
        << "Could not create authenticatee module '"
        << authenticateeName << "': " << module.error();
    }
    LOG(INFO) << "Using '" << authenticateeName << "' authenticatee";
    authenticatee = module.get();
  }

  CHECK_SOME(credential);

  // We pick a random duration between `minTimeout` and `maxTimeout`.
  Duration timeout =
    minTimeout + (maxTimeout - minTimeout) * ((double)os::random() / RAND_MAX);

  authenticating =
    authenticatee->authenticate(master.get(), self(), credential.get())
      .onAny(defer(self(), &Self::_authenticate, minTimeout, maxTimeout))
      .after(timeout, [](Future<bool> future) {
        // NOTE: Discarded future results in a retry in '_authenticate()'.
        // This is a no-op if the future is already ready.