Capture sessions

A session is a trial: several systems started together, recorded, and stopped together, with an id that every system reports.

$ ros2 mocap4r2 record --session walk01                  # all systems
$ ros2 mocap4r2 record optitrack_driver --session walk02 --topics /odom /imu

record starts the systems with the session id (and fails without recording if one of them cannot start), records with rosbag2 every topic they announce plus /tf, /tf_static, /mocap4r2/systems, /diagnostics and the extra --topics, and on Ctrl-C stops the bag and the systems. The bag directory gets a mocap4r2_session.yaml with the session, the start and end times and, for each system, its type, frame, rate and topics.

Other devices in a session

Any device can join the sessions as an auxiliary system: it is started and stopped with the mocap systems and its topics are recorded with them.

emg_recorder:
  ros__parameters:
    topics:
      - emg/raw:std_msgs/msg/Float64MultiArray
      - emg/status

$ ros2 launch mocap4r2_control auxiliar.launch.yaml params_file:=emg.yaml

From C++, derive from mocap4r2_control::MocapSystemNode to react to the start and stop of each session (on_control_start/on_control_stop receive the session id).