Run the foreman on the client.

def ProcessMessage(self, message):
    """Run the foreman on the client."""
    # Only accept authenticated messages
    if (message.auth_state !=
        rdf_flows.GrrMessage.AuthorizationState.AUTHENTICATED):
      return

    now = time.time()

    # Maintain a cache of the foreman
    with self.lock:
      if (self.foreman_cache is None or
          now > self.foreman_cache.age + self.cache_refresh_time):
        self.foreman_cache = aff4.FACTORY.Open(
            "aff4:/foreman", mode="rw", token=self.token)
        self.foreman_cache.age = now

    if message.source:
      self.foreman_cache.AssignTasksToClient(message.source.Basename())