How to run yarplogger and modules in one single application without yarprun

[pattacini]

If you have just one PC - no cluster then - and want to launch everything in one single application, the template below might come in handy:

<application>
  <name>Great application with yarplogger and without yarprun</name>

  <module>
      <name>yarplogger</name>
      <parameters>--start</parameters>
      <node>localhost</node>
  </module>

  <module>
      <name>module</name>
      <dependencies>
         <port timeout="10">/yarplogger</port>
      </dependencies>
      <environment>YARP_FORWARD_LOG_ENABLE=1</environment>
      <node>localhost</node>
  </module>
</application>

Closing remarks

• We rely on localhost broker, given that we don't have to deal with a cluster, hence there's no need for yarprun.
• yarplogger becomes already operative (notice the --start option), so we don't even need to click on the start button within the GUI.
• The module is launched only when the port /yarplogger is alive on the network (we enforce a 10 s timeout though). Thereby, we make sure that yarplogger is running in order not to miss any precious printout that will be yielded at module startup.
• The module runs with a special environment variable that tells Yarp to redirect printouts toward yarplogger. (Note that, when we rely on yarprun launched with --log option, we don't need to do that.)

Now you're only one click away from your experiment.

[pattacini]

And if you aim not to miss any printout even when you shut down the whole application, just specify the yarplogger's option --no_stop.