ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange

Attention: Answers.ros.org is deprecated as of August the 11th, 2023. Please visit robotics.stackexchange.com to ask a new question. This site will remain online in read-only mode during the transition and into the foreseeable future. Selected questions and answers have been migrated, and redirects have been put in place to direct users to the corresponding questions on Robotics Stack Exchange. Additional details are available here.

2

[rospy] Disable message queue

asked 2013-04-09 23:20:25 -0600

flag of Czech Republic

801 ●47 ●57 ●67

Hi,

I have a some computation that takes a while connected to topic. I wan't that next message for computation is as fresh as possible. I have tried setting the queue to zero which results in error and setting it to one doest much help.

sub = rospy.Subscriber("~input",i nput_cb, queue_size = 1)

Test output:

[INFO] [WallTime: 1365585376.358492] msg is 0.2299852 s old!
[INFO] [WallTime: 1365585377.532643] msg is 1.3721399 s old!
[INFO] [WallTime: 1365585378.706446] msg is 1.4059465 s old!
[INFO] [WallTime: 1365585379.863709] msg is 2.5273464 s old!
[INFO] [WallTime: 1365585383.380832] msg is 2.5602341 s old!
[INFO] [WallTime: 1365585385.704427] msg is 2.5397372 s old!
[INFO] [WallTime: 1365585386.877181] msg is 2.5365553 s old!

edit retag flag offensive close merge delete

2 Answers

Sort by » oldest newest most voted

0

answered 2013-04-10 01:28:57 -0600

Martin Günther

flag of Germany

11816 ●82 ●159 ●198 https://www.dfki.de/en...

I'm not sure what's wrong with that code, but you can achieve what you want to do by using rospy.wait_for_message instead of a Subscriber.

edit flag offensive delete link

1

answered 2013-04-12 06:00:42 -0600

flag of United States of America

58457 ●128 ●550 ●526 http://www.ros.org/

Your delay may be coming from the publisher queue as well. You should make sure that it is small/size 1 too.

edit flag offensive delete link

Comments

What if your publisher is a python node? There is no queue size parameter for publishers in rospy.

juancamilog ( 2013-08-13 20:00:34 -0600 )edit

Question Tools

Stats

Asked: 2013-04-09 23:20:25 -0600

Seen: 813 times

Last updated: Apr 12 '13

Related questions

ROS Answers is licensed under Creative Commons Attribution 3.0 Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.

Powered by Askbot version 0.10.2