[ros-users] trigger goal from inside actionlib server

Blaise Gassend blaise at willowgarage.com
Mon Oct 18 19:35:39 UTC 2010


Where is your triggerGoalInternallyCallback being called from? If it
is being called from ROS on the same queue that your ActionServer is
using then I would expect this code to deadlock. Indeed, ROS would be
waiting for triggerGoalInternallyCallback to return before calling
subsequent callbacks, and those callbacks are necessary for the action
to get carried out.

Blaise

On Mon, Oct 18, 2010 at 12:27 PM, Axelrod, Benjamin <baxelrod at irobot.com> wrote:
> Thanks.  I did try to create a client inside the server.  For some reason I
> thought it didn’t work. But maybe I messed something up.  I think it would
> hang when I called tempclient.waitForServer().
>
>
>
> Vijay: I don’t want the server to be active on a null goal.  I do want a
> goal.  I want to provide the goal from inside the client.  This is to
> simplify testing and debugging.
>
>
>
> This is the pattern I am looking for:
>
>
>
> void MyActionServer::goalCallback()
>
> {
>
>     // accept goal from client
>
>     goal_ = *server_.acceptNewGoal();
>
>     this->performAction(goal_);
>
> }
>
>
>
> void MyActionServer::triggerGoalInternallyCallback()
>
> {
>
>     // create a goal for internal testing
>
>     MyActionServerGoal tempGoal;
>
>     tempGoal.foo = “bar”;
>
>     this->performAction(tempGoal);
>
> }
>
>
>
> However, I have no performAction() method.  And because the service routine
> uses a timer, and relies on the server being active, it is not so easy to
> split out.
>
>
>
> So, ideally, I would have this:
>
>
>
> void MyActionServer::triggerGoalInternallyCallback()
>
> {
>
>     // create a goal for internal testing
>
>     MyActionServerGoal tempGoal;
>
>     tempGoal.foo = “bar”;
>
>     this->server_->setGoal(tempGoal);
>
> }
>
>
>
> Which would then trigger the MyActionServer::goalCallback().
>
>
>
>
>
>
>
> From: ros-users-bounces at code.ros.org [mailto:ros-users-bounces at code.ros.org]
> On Behalf Of Vijay Pradeep
> Sent: Monday, October 18, 2010 1:21 PM
> To: User discussions
> Subject: Re: [ros-users] trigger goal from inside actionlib server
>
>
>
> Hi Ben,
>
> If this is what you want to do, I would go with Blaise's suggestion and send
> a goal using the action client with no callbacks registered.
>
> However, I'm not really sure why you would want to have the
> SimpleActionServer be active on null goal.  Understanding your use case
> would help us get a feel for exactly what functionality you need.
>
> Vijay
>
> On Mon, Oct 18, 2010 at 9:44 AM, Blaise Gassend <blaise at willowgarage.com>
> wrote:
>
> Hi Ben,
>
> On Mon, Oct 18, 2010 at 9:06 AM, Axelrod, Benjamin <baxelrod at irobot.com>
> wrote:
>> I have an actionlib server and I would like to be able to trigger its own
>> goal.  I don’t need any callbacks for goal accepted, feedback, or even
>> result.  I just want to manually set the server to be active.  Is this
>> possible?  I can’t figure out a way to do this.
>
> Why don't you use a SimpleActionClient to set the goal? If you don't
> specify the callbacks when setting you call sendGoal, those callbacks
> default to being null. Is that not what you want?
>
> http://www.ros.org/doc/api/actionlib/html/classactionlib_1_1SimpleActionClient.html#ae6a2e6904495e7c20c59e96af0d86801
>
>> It might be nice if  actionlib::SimpleActionServer::acceptNewGoal() was
>> overloaded to accept a goal parameter.  That would set the server active,
>> but with NULL callbacks.
>
> Is there a strong reason for wanting to do this without explicitly
> having a client?
>
> Blaise
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>
>
> --
> Vijay Pradeep
> Systems Engineer
> Willow Garage, Inc.
> vpradeep at willowgarage.com
>
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>
>



More information about the ros-users mailing list