Export pprz messages into OpenDDS format

podhrmic commented 6 years ago

OpenDDS is an open source implementation of Publisher-Subscriber communication service (more info here http://opendds.org/).

This PR adds an option to generate OpenDDS compatible IDL format from messages.xml.

More information and an example of OpenDDS<-->Pprzlink communication will follow, but I am seeking some early feedback on the Python implementation. Plus this works as is.

gautierhattenberger commented 6 years ago

as a side note, where and how are you using this OpenDDS ?

podhrmic commented 6 years ago

I have to interface paparazzi with a system that uses OpenDDS - imagine a mission computer . The details are still in the working, but I wanted to share what I have so far.

flixr commented 6 years ago

Without looking at the details, this is not really OpenDDS specific, right? It should work for any DDS compliant implementation... so this should probably be reflected in the naming i.e. PROTOCOL_DDS vs PROTOCOL_OPENDDS.

Also is it a spec on the DDS or RTPS (RealTimePublishSubscribe) level?

podhrmic commented 6 years ago

Good point - any system that understands IDL format can in theory use it.

From FAQ:

Starting with version 3.1, OpenDDS contains an implementation of the RTPS (Real Time Publish-Subscribe) specification required for interoperability.

Does that answer your question?

podhrmic commented 6 years ago

For bookkeeping purposes, I am describing here what needs to happen to make this actually useful.

Generated code

[x] From Messages.xml generate $MSG_CLASS_NAME.idl for each class. Already done.
[x] Generate type support for each class from the IDL file. Already done.
[ ] For each message generate DataReaderListener.h/.cpp that handles properly message variables (mostly for logging purposes).
[ ] Optional: figure out better type mappings than the current ones (i.e. char[] -> ?)

Topics

The suggested topics follow the message class names:

Telemetry
Datalink
etc...

Application code

In order to make a useful application (such as OpenDDs - Pprzlink translator), the following is needed (for a simple "link" application):

[ ] main.cpp with a reader and a writer for each message in given topic
[ ] Reader: gets OpenDDS message and writes pprz message on ivy bus
[ ] Writer: binds to ivy messages, once a new message is received, parse & write it to OpenDDS

OpenUAS commented 3 years ago

Integrating DDS would be welcomed, maybe I shoud add it to the "list" ;)

paparazzi / pprzlink