Note: This tutorial assumes that you have completed the previous tutorials: Advertising and Pulling.
(!) Please ask about problems and questions regarding this tutorial on answers.ros.org. Don't forget to include in your question the link to this page, the versions of your OS & ROS, and also add appropriate tags.

Writing Gateway Launchers

Description: Tips on writing launchers that incorporate a gateway into your ros master.

Keywords: rocon, gateway

Tutorial Level: INTERMEDIATE

Tips

There are some key features that are typical to most gateway launchers:

  • Public Args: exposing variables to users who'd like to modify behaviour from their own launcher

  • Firewalling: blocking anything coming into your robot

  • Default Flips/Pulls: setting a few regular expression rules to define flips/pulls that you want activated by default (saves alot of service calling).

  • Hub Whitelists/Blacklists: be selective about where your gateway interacts on the lan.

Example

The following is a launcher used by the rocon_app_manager and demonstrates all of the above features.

<launch>
  <arg name="gateway_name" default="gateway"/>
  <!-- Polling period for multimaster advertising/flipping -->
  <arg name="gateway_watch_loop_period" default="5"/>
  <!-- semi-colon separated hub names/regex patterns -->
  <arg name="hub_whitelist" default=""/>
  <node pkg="rocon_gateway" type="gateway.py" name="gateway">
    <rosparam command="load" file="$(find rocon_gateway)/param/default.yaml" />
    <rosparam command="load" file="$(find rocon_gateway)/param/default_blacklist.yaml" />
    <rosparam command="load" file="$(find rocon_app_manager)/param/app_manager_advertisements.yaml" />
    <rosparam command="load" file="$(find rocon_app_manager)/param/app_manager_flips.yaml" />
    <!-- The paired hub, if available -->
    <rosparam param="hub_uri">http://localhost:6380</rosparam>
    <param name="name" value="$(arg gateway_name)"/>
    <!-- Nothing comes in! -->
    <rosparam param="firewall">true</rosparam>
    <param name="watch_loop_period" value="$(arg gateway_watch_loop_period)"/>
    <param name="hub_whitelist" value="$(arg hub_whitelist)"/>
  </node>
</launch>

Wiki: rocon_gateway_tutorials/Tutorials/hydro/Writing Gateway Launchers (last edited 2013-08-26 16:29:52 by DanielStonier)