Alexey Ozhigov's profile - activity

The problem is that if you have a launch file with several nodes, all of which perform some processing of fixed set data of predefined size, all of the nodes should know when the processing task they are running for is finished so that all the nodes terminate. Yes, I am now doing kill by PID.

Hi,

I have a launch file that starts several nodes, one of which processes a video file and publishes messages to topics, on per video frame basis. Other nodes listen to those topics and process the received messages. I would like to run this launch file in a script with different video files passed as launch file parameters. The issue is that the listening nodes do not know when the publisher node terminates, and thus roslaunch does not return since listening nodes are still running even though there are going to be no data published on the topics.

I can think of setting timers in the listening nodes and signal_shutdown(.) them if time lapse since last received message exceeds some predefined threshold, but I suppose there may be better solutions. I cannot send shutdown signal from one node to terminate another node within ROS API, right? What options (other than timer) do I have in order to implement that architecture in ROS?

tfoote's explanation makes perfect sense to me. I would say the doc. is quite vague on the purpose of ROS_HOME: On ROS/EnvironmentVariables page it says: By default, ROS writes data to ~/.ros. This location can be changed by setting ROS_HOME. No such phrasing as ROS tools, just ROS.

I have put $HOME as an example, but the idea is to set it to $(find <package_name>), so that nodes launched from the file create files w.r.t. location of the package containing that launch file. Exporting ROS_HOME outside launch file from bash would of course be one of the options, but I would like to be able to use env tag, since ROS documentation on ROS_HOME says it should work as expected, at least as I expect it to work.

Hi!

I want to have a current directory for my node different than ~/.ros, so that when I create files in my node providing only local file name, they are saved relevant to my given $ROS_HOME. I tried the following launch file:

<?xml version="1.0"?>
<launch>
   <env name="ROS_HOME" value="/home/alex" />
   <node name="test" type="test.py" pkg="simple_pcl" output="screen"/>
</launch>

But the file I am creating still appears in ~/.ros. Here is the node source:

#!/usr/bin/python

import os

if __name__ == '__main__':
    os.system('touch test_file')

I also tried setting ROS_HOME inside node entry:

<?xml version="1.0"?>
<launch>
  <node name="test" type="test.py" pkg="simple_pcl" output="screen">
    <env name="ROS_HOME" value="/home/alex" />
  </node>
</launch>

also without success. What do you think is the problem?