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ROS Bag Recording

ROS bags are the primary method for recording data during robot operation. They capture ROS 2 topics for later analysis, debugging, and algorithm development.

Managed Recording

AirStack manages recording with the bag_recorder_pid package: launch the stack with RECORD_BAGS=true to start the recorder node, then toggle recording via its bag_record/set_recording_status topic (std_msgs/Bool, in the robot namespace). See the Logging overview for the full workflow.

Configuration

Topic Selection

Choose topics based on mission objectives. The recorder's config file (selected with LOG_CONFIG, in logging_bringup/config/, default log.yaml) groups topics into named sections; relative topic names are prefixed with the robot namespace:

Minimal set (state and commands): 

sections:
  state:
    mcap_qos: mcap_qos.yaml
    args: []
    topics:
      - odometry_conversion/odometry
      - global_plan
      - trajectory_controller/trajectory_segment_to_add

Full set (everything for debugging — record all topics except an exclude list): 

sections:
  everything:
    mcap_qos: mcap_qos.yaml
    args: []
    exclude:
      - /tf
      - /tf_static

Section args are passed through to ros2 bag record, so storage limits like -b 4000000000 (split at ~4 GB) or --max-cache-size go there — see the shipped log.yaml for a working example.

Storage Locations

Development (Docker)

  • Bags stored in mounted volume: robot/bags/ (mounted at /bags in the container)
  • Persists across container restarts

Hardware Deployment

  • Jetson (l4t profile): ${BAG_STORAGE_PATH} on the device (default /media/airlab/Storage/airstack_collection) is mounted at /bags
  • The recorder's target directory is its output_dir parameter (set in logging.launch.xml, default /bags)

Manual Recording and Playback

For one-off captures the standard CLI works as usual inside the robot container — see the ROS 2 bag documentation for the full reference:

ros2 bag record /robot_1/odometry_conversion/odometry /robot_1/global_plan
ros2 bag play path/to/bagfile
ros2 bag info path/to/bagfile

Topics are namespaced by robot name (/robot_1/... with the default robot name map).

To extract specific topics into a new bag, use ros2 bag convert with an output spec: 

ros2 bag convert -i input_bag -o out_spec.yaml


# out_spec.yaml
output_bags:
  - uri: output_bag
    topics: [/robot_1/odometry_conversion/odometry, /robot_1/global_plan]

Integration with Data Offloading

For transferring bags from robot to a storage server, see the Data Offloading Guide.

See Also