> For the complete documentation index, see [llms.txt](https://carec.gitbook.io/carec-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://carec.gitbook.io/carec-docs/documentation/simulation/rosbag2-recording-and-replay.md).

# rosbag2 Recording and Replay

Bag files connect simulation, field observations, and repeatable debugging. Define topic profiles so contributors record enough evidence without capturing unnecessary personal data.

| Profile    | Typical content                                          | Purpose                             |
| ---------- | -------------------------------------------------------- | ----------------------------------- |
| Core       | Commands, modes, safety state, TF, odometry, diagnostics | Always-on regression evidence       |
| Navigation | Core plus maps, costmaps, plans, controller outputs      | Planner/controller analysis         |
| Perception | Core plus selected sensor streams and detections         | Perception debugging                |
| Full lab   | All approved topics                                      | Time-bounded controlled experiments |

## Recording metadata

Record CAREC commit, container image, parameter hashes, calibration version, world/scenario ID, seed, operator, test purpose, start/end time, and privacy classification next to the bag.

## Replay rules

* Use simulated time consistently and verify all replayed nodes subscribe to `/clock`.
* Do not replay actuator commands into hardware.
* Isolate replay namespaces or disable live drivers.
* Check QoS compatibility and document topics that cannot be replayed faithfully.
* Evaluate the same assertions used by live simulation when possible.

{% hint style="danger" %}
Images, audio, location, and user interaction may contain sensitive data. Collect the minimum necessary, control access, document consent and retention, and redact before public issue reports.
{% endhint %}


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