Can Ardent nodes talk to Bouncy nodes?

According to the release notes for Bouncy and observed behavior, it does not use partitions anymore for namespaces.

From https://github.com/ros2/ros2/wiki/Release-Bouncy-Bolson:

The ROS topic names containing namespaces are mapped to DDS topics including their namespaces. DDS partitions are not being used anymore for this.

Is there any backwards compatibility?

Asked by calvertdw on 2018-08-16 18:30:29 UTC

Comments

My experiments with docker ardent-basic and bouncy-basic fail, but bouncy-basic containers can talk to each other.

Asked by calvertdw on 2018-08-16 18:31:43 UTC

Do you have a specific use case why you need to mix both releases? If there anything which works for you with the Ardent release but not for the Bouncy release? Otherwise you should be able to just move forward to Bouncy.

Asked by Dirk Thomas on 2018-08-17 00:19:42 UTC

Bouncy does not work on 16.04 and we have robots on both 16.04 and 18.04. This is a problem because it is hard to switch between bouncy and ardent on our development computers. The robots on 16.04 require "certified" software (i.e. slow moving code with little to no maintenance personnel)

Asked by calvertdw on 2018-08-20 10:20:03 UTC

From the Bouncy release page, building Bouncy from source on 16.04 is supported, but binary packages aren't being provided.

Asked by mjcarroll on 2018-08-20 10:27:39 UTC

@calvertdw can you provide more details about what bouncy nodes dont work for you in Xenial?

AFAIK all bouncy ROS 2 packages work on both platforms. The few exceptions are: cartographer and cv_bridge. A xenial build of the bouncy release is available at ...

Asked by marguedas on 2018-08-20 11:57:51 UTC

... https://github.com/ros2/ros2/releases/download/release-bouncy-20180720/ros2-bouncy-linux-xenial-x86_64.tar.bz2

Asked by marguedas on 2018-08-20 11:58:08 UTC

I missed that bouncy was supported on 16.04, so I did not have any nodes that weren't working. Thank you.

Asked by calvertdw on 2018-08-20 14:58:08 UTC

Answers

If the topic name doesn't contain a namespace it should be compatible between Ardent and Bouncy.

If the topic name does contain a namespace it won't be compatible between Ardent and Bouncy (assuming the RMW impl. in Ardent was mapping the namespace to a DDS partition which was e.g. the case for the default RMW impl. FastRTPS). Technically in this case the protocol is different and there not compatible.

Asked by Dirk Thomas on 2018-08-17 00:19:43 UTC