Creating Runner Plugins

The runner API is designed to be extensible, so that specific runners can be created on a per provider basis. Another feature that can be implemented is cross-runner communication, which could allow capabilities to be combined at runtime to perform more complex tasks. This could overcome limitations in robot programming in which there is a common need for extensive pre-definition of tasks.

Inheritance

A runner is a plugin that inherits from the capabilities2_runner::RunnerBase class. The RunnerBase class is a pure virtual class that defines the interface for a runner. The RunnerBase class has the following methods:

1. start - starts the runner

1. stop - stops the runner

1. trigger - triggers the runner

Multiple classes are provided to inherit from, depending on the type of runner you want to create. A notable example is the capabilities2_runner::ActionRunner class, which is used to create runners that run actions.

Export with Pluginlib

The runner should be exported as a plugin using the PLUGINLIB_EXPORT_CLASS macro.

#include <capabilities2_runner/runner_base.hpp>
#include <pluginlib/class_list_macros.hpp>
 
...
 
PLUGINLIB_EXPORT_CLASS(capabilities2_runner::MyRunner, capabilities2_runner::RunnerBase)

Expose with plugins.xml

The runner should be exposed as a plugin in the plugins.xml file.

<library path="capabilities2_runner">
    <class type="capabilities2_runner::MyRunner" base_class_type="capabilities2_runner::RunnerBase">
        <description>
            A plugin that provides a  my-runner to test capabilities2
        </description>
    </class>
</library>

plugin.xml needs to be included in the CMakeLists.txt.

pluginlib_export_plugin_description_file(${PROJECT_NAME} plugins.xml)