Race conditions in YARP Plugins

[jgvictores]

This issue is a follow-up on #47 (comment).

Regarding the use of the main() function of OpenRAVE plugins, it is stated that "Robots might not necessarily be set before this function call". Current state:

• We mostly want main() for CLI support, where this race condition does not happen, such as:

openrave /usr/local/share/teo-openrave-models/openrave/teo/teo.robot.xml --module OpenraveYarpPluginLoader "open --device controlboardwrapper2 --subdevice YarpOpenraveControlboard --robotIndex 0 --allManipulators"

• This race condition does always occur via openrave.py. This is bad, but not terrible as we can always load the plugins via scripts as in the examples. Example of failure:

openrave.py -i /usr/local/share/teo-openrave-models/openrave/teo/teo.robot.xml --module OpenraveYarpPluginLoader "open --device controlboardwrapper2 --subdevice YarpOpenraveControlboard --robotIndex 0 --allManipulators"

[jgvictores]

The priority of this issue is low, because:

• Failure has not been observed in the CLI use case.
• There is a workaround for Python, which is loading the plugin within the Python script.

[jgvictores]

Careful with what is described here:

Via CLI, OpenRAVE::SensorBase::CC_PowerOn has no apparent effect. This is bad...

[jgvictores]

Via CLI, OpenRAVE::SensorBase::CC_PowerOn has no apparent effect. This is bad...

Not only via OpenraveYarpPluginLoader: all OpenRAVE::SensorBase::CC_PowerOn via CLI.

[jgvictores]

No results with (locking env has no effect, and ret is 1 both on fail and success):

{
    OpenRAVE::EnvironmentMutex::scoped_lock lock(penv->GetMutex()); // lock environment
    int ret = sensorBasePtr->Configure(OpenRAVE::SensorBase::CC_PowerOn, true);
    CD_DEBUG("CC_PowerOn: %d\n", ret);
 }

[jgvictores]

Note that https://github.com/rdiankov/openrave/blob/v0.9.0/src/cppexamples/orshowsensors.cpp does actually work.

[jgvictores]

openrave.py -i /usr/local/share/teo-openrave-models/openrave/teo/teo.robot.xml --module OpenraveYarpPluginLoader "open --device controlboardwrapper2 --subdevice YarpOpenraveControlboard --robotIndex 0 --allManipulators"

We can avoid the "robot" vs "plugin" race condition via new syntax which loads the env first within the plugin (#99 (comment)): openrave.py -i --module OpenraveYarpPluginLoader "env openrave/teo/teo.robot.xml open --device controlboardwrapper2 --subdevice YarpOpenraveControlboard --robotIndex 0 --allManipulators"

[jgvictores]

Leaving this issue open to research on OpenRAVE::SensorBase::CC_PowerOn, which (hopefully) may be due to something as simple as not starting the simulation.

[jgvictores]

Mostly solved via e3dfd77.

Still, via yarpdev:

1. Sometimes collision ODE is not set -> force it via the GUI.
2. Sometimes simulation does not start (can occur in large environments) -> force it via the GUI (make sure Options > Simulation checked)

Therefore, the OpenraveYarpPluginLoader approach (perma) is preferred, via CLI and/or Python.

[jgvictores]

• Sometimes collision ODE is not set -> force it via the GUI.

Fixed via 3e387ec (--collision was not being treated, now it is).

2. Sometimes simulation does not start (can occur in large environments) -> force it via the GUI (make sure Options > Simulation checked)

It wasn't large environments and race conditions. It was the RGBD without Depth example, fixed via 033a5d0

Closing issue!