Requires core to be open just to examine bag file

[dirk-thomas]

From @DLu on August 12, 2015 18:11

I believe with rxbag you could just open bag files to examine them without a core. However, rqt_bag requires a core, even without trying to publish anything.

Copied from original issue: ros-visualization/rqt_common_plugins#332

[dirk-thomas]

In rqt the type of a plugin determines if it requires a ROS node or not. The infrastructure currently does not allow to start as non-ROS-node-plugin and then request a ROS node afterwards. Therefore it is currently not possible to implement the requested feature in a single plugin.

I would be possible though to refactor rqt_bag into two plugins: one which does not allow to publish and one with the current functionality. Not a nice approach though.

[DLu]

I primarily use rqt_bag to see the timeline of a bagfile and inspect the contents. I rarely use it for playing back the messages. Other people's mileage may vary.

I think the ideal solution would be a command line flag that specifies whether you will want to publish or not. I'm unclear if that would still require two plugins.