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"Attempting to accept the next goal when a new goal is not available"

asked 2017-08-04 12:23:10 -0600

Canni gravatar image

updated 2017-08-05 00:22:41 -0600

NEngelhard gravatar image

Hello! I'm trying to perform an action-client/action-server structure using a callback structure.

So it just has to read info from the goal and publish messages on a turtlesim topic.

When I run this node (either before or after I created the client) every time the server receives a Goal I get this:

[ INFO] [1501865084.462187784]: Server Created    
[ INFO] [1501865086.638608252]: I'm in goalCB() and I'm receiving a new Goal
[ERROR] [1501865086.638780375]: Attempting to accept the next goal when a new goal is not available

This is my code (which btw for now does nothing, I just wanted to see if everything worked)

class polygonAction
polygonAction(std::string name) : 
    as(nh_, name, false),

//register the goal and feeback callbacks
as.registerGoalCallback(boost::bind(&polygonAction::goalCB, this));
as.registerPreemptCallback(boost::bind(&polygonAction::preemptCB, this));
ROS_INFO("Server Created");

//Stuff for turtlesim we don't care




  void goalCB()
    ROS_INFO("I'm in goalCB() and I'm receiving a new Goal");
    goal_length = as.acceptNewGoal()->length;
    goal_sides = as.acceptNewGoal()->sides;
    ROS_INFO("Received %d sides and %d lenght", goal_sides, goal_length);


  void preemptCB()
    ROS_INFO("%s: Preempted", action_name_.c_str());
    // set the action state to preempted

  //Stuff for turtlesim we are not interested in 


  ros::NodeHandle nh_;
  actionlib::SimpleActionServer<es_1::polygonAction> as;
  std::string action_name_;
  int goal_sides, goal_length, sides_count;
  es_1::polygonFeedback feedback_;
  es_1::polygonResult result_;
  ros::Publisher pub;
  ros::Subscriber sub;


int main(int argc, char** argv)
  ros::init(argc, argv, "polygon_action_server");

  polygonAction polygon("polygon");


  return 0;


Any ideas?

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It's better to include only the important information in your question. This question is only about the mechanics of an action server, the turtle-sim or your polygon are not relevant but just a distraction.

NEngelhard gravatar image NEngelhard  ( 2017-08-04 14:26:04 -0600 )edit

Yeah sorry, but they were only few lines and they had comments above so i just copied and pasted my code

Canni gravatar image Canni  ( 2017-08-04 17:45:35 -0600 )edit

I modified the code ;)

Canni gravatar image Canni  ( 2017-08-04 17:55:54 -0600 )edit

1 Answer

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answered 2017-08-04 14:24:47 -0600

NEngelhard gravatar image

You can only accept a new goal once, but you have two calls of as.acceptNewGoal(). so just call it once to get a pointer to the current goal. You can check the implementation here.

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RIGHT! Thank you so much! Now I'm trying to get my goal in that goalCB but I don't know how to instantiate it ahahah I'm a total noob in ROS so thank you for your advices!

Canni gravatar image Canni  ( 2017-08-04 17:53:08 -0600 )edit

Ok done! Thank you so much!

Canni gravatar image Canni  ( 2017-08-04 18:00:39 -0600 )edit

How did you get around this? I just fixed the same error, also being a total noob

TheMilkman92 gravatar image TheMilkman92  ( 2021-04-14 22:26:52 -0600 )edit

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Asked: 2017-08-04 12:23:10 -0600

Seen: 806 times

Last updated: Aug 05 '17