Update CARLA Ambassador to use XMLRPC Client

[paulbourelly999]

PR Details

Description

Add logic to CARLA Ambassador to use XMLRPC Client to dynamically create sensor and retrieve detections. More specifically: the CARLA Ambassador will now create a CARLA XML RPC Client on startup. Its configuration parameters (constructor arguments) will be loaded from the carla_config.json configuration file for the CARLA Ambassador. This is currently limited to carlaCDASimAdapterUrl which tells the XMLRPC client where the XMLRPC server is hosted.
Next the CARLA Ambassador now listens for Detector Registration Interactions which are triggered by the Infrastructure Ambassador in response to infrastructure registration attempts that include sensors. When receiving a Detector Registration Interaction, the CARLA Ambassador will tell the CARLA XML RPC Client to make a create_sensor request for each detector registration interaction to create the sensors in CARLA. On each timestep, which should be at 100 ms intervals, the CARLA Ambassador will now also call get_detections for every successful create_sensor attempt. This means that all the created sensor in CARLA will have their detections polled at the same interval as the CARLA Ambassador runs processTimeAdvanceGrant. The detections retrieved from the CARLA CDA Sim Adapter via the XMLRPC client will be serialized into DetectedObject(s) from json and triggered as interactions for other listening Ambassadors, mainly the infrastructure ambassador.

Related Jira Key

CDAR-209

Related Issue

#211

Motivation and Context

Add CARLA Sensor pipeline for creating sensors and getting detections for CARMA-Streets

How Has This Been Tested?

Unit testing

Types of changes

• Defect fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that cause existing functionality to change)

Checklist:

• I have added any new packages to the sonar-scanner.properties file
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
  CARMA Contributing Guide
• I have added tests to cover my changes.
• All new and existing tests passed

[paulbourelly999]

@kjrush Do you have any information why were are requesting time advance like this with a continuously incremented counter? If you have any information about executedTimes and why its used in our requestAdvanceTime.

[kjrush]

I did a quick skim of the rest of this PR, but so far focused on this.

I don't really see what purpose this executed times has, to be honest. It might just be entirely unnecessary. For the record, it doesn't increment infinitely. It's actually reset later on in the code inside the receiveInteraction(SimulationStepResponse) method. The interactions being received there seem to be generated whenever SUMO provides a new TraCI update, so it should be frequently, so this should never go above a small value, maybe 10 at most.

But even 10 doesn't make much sense, considering this requestAdvanceTime arg is in milliseconds, and there's no multiplicative factor applied to this executedTimes value (unlike carlaConfig.updateInterval above), so it's small enough it probably doesn't actually do anything. I imagine it was implemented like this with the goal that if we don't have any fresh data from sumo, we should wait longer to delay the CARLA updates until we do have fresh data. But I'm not sure that's needed and it seems unlikely this is actually accomplishing that.

I think you were right to be questioning about this line, but in the end I'm not sure it matters one way or the other. I'd be in favor of just removing it, but keeping this line in our mental bookmarks in case we run into issues with the ambassador. If we hit those issues we'll have this top of mind to re-investigate.

[sonarcloud]

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0 Bugs
0 Vulnerabilities
0 Security Hotspots
2 Code Smells

77.5% Coverage
0.0% Duplication

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