Unsupported RMW implementation in ROS2

Question

I am trying to build my overlay workspace with RTI Connext. For that, I set the environment variable as export RMW_IMPLEMENTATION = rmw_connext_cpp. While building the overlay workspace, I receive a build error as `

The RMW implementation has been specified as 'rmw_connext_cpp' through the
environment variable 'RMW_IMPLEMENTATION', however it is not in the list of
supported rmw implementations, which was specified when the
'rmw_implementation' package was built.

I was going through this documentation and thus tried to use the --force-cmake-configure flag while building. But the same problem persists.

So I removed the build and the install folder and tried to build again but with the same error.

What am I doing wrong ?

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Originally posted by aks on ROS Answers with karma: 667 on 2018-06-20

Post score: 0

Answer 1

If your underlay workspace doesn't support Connext you can't simply enable it in your overlay. The recommended way would be to build ROS 2 (all of it) from source.

You could probably get away with an overlay but that workspace must contain all packages which are influenced by the available rmw implementation. That would include the rmw_connext (all pkgs of the repo), the pkgs rosidl_typesupport_c(pp), rmw_implementation as well as any package containing messages / services. (Maybe I am forgetting some so building all of ROS 2 from source is certainly the safer bet.)

Btw. the upcoming Bouncy release (~ next week) will provide support Connext built-in. So there is no need to rebuild anything "in the underlay".

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Originally posted by Dirk Thomas with karma: 16276 on 2018-06-20

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by aks on 2018-06-20:
Thanks for the information. Do you mean that Bouncy will have Connext as bundled DDS i.e. set as default instead of fastrttps ?

Comment by Dirk Thomas on 2018-06-20:
Yes and no. Bouncy will ship prebuilt binaries supporting FastRTPS, Connext, and OpenSplice. FastRTPS is still the default rmw implementation.

Comment by Dirk Thomas on 2018-06-20:
The goal is that when installing the Debian packages only FastRTPS will be pulled in automatically. The user can install additional Debian packages to add Connext and/or OpenSplice support.

Comment by uthinu on 2018-09-06:
I have built Bouncy from source, but it seems that it does not support Connext as well. How can I configure/check ROS2 so that it builds all RMW included?

Comment by Dirk Thomas on 2018-09-06:
You need to have Connect installed and sourced when building from source. If you need further information please consider to open a separate question.