How to replay CAN bus logs

Replay recorded CAN bus messages, with no CAN bus adapter needed, to test dashboards, rules, and custom components without live CAN bus data, or to debug a component configuration against a recording. The CAN Data Log Replayer replays log files that were recorded earlier in Profinity. For how to record a log, refer to Log / replay CAN bus messages.

Before you start, you need:

• Profinity running.
• A recorded CAN bus log file. It comes from the CAN File Logger or the CAN SFTP Logger (refer to CAN file and SFTP loggers), or it is the example_log.csv supplied with Profinity. SFTP is the Secure Shell (SSH) File Transfer Protocol. Logs from InfluxDB or Prometheus cannot be replayed, so use a File or SFTP logger to record logs for later replay.
• The Replay CAN logs permission (refer to Roles and permissions), which provides the CAN LOG REPLAY side-menu entry and also turns on View CAN data.
• A profile whose components match the recording. Only components whose CAN addresses match the logged messages receive data. example_log.csv carries the CAN traffic of the Example Profile's components, so load the Example Profile first (refer to the Quick start guide).

Replay a log

Replay mixes with live traffic

Profinity processes replayed messages as if it had received them from the bus. Tags, dashboards, rules, and alerts react to them alongside any live traffic from a connected adapter. Disconnect the adapter, or isolate the live hardware from the bus, before you replay a log. Otherwise the live and replayed values compete.

The replayer lists only the can_bus_logs/replay/ folder in the artefacts directory, which sits in a different place on each platform. To replay a log:

1. Select CAN UTILITIES in the side menu, then CAN LOG REPLAY. The CAN Data Log Replayer opens and lists the available log files.
2. If the log file is not listed, for example a file recorded earlier or on another Profinity instance, add it in one of two ways:
   • Copy it into the can_bus_logs/replay/ folder.
   • Use the Upload CAN Log files control and select the file.

The file then appears in the list. 3. Select the log file in the list, then select Play. Replayed messages appear in the CAN Activity panel, which How to send and receive CAN bus messages describes. Components receive the messages, dashboards update, and the slider shows the position in the log.

An uploaded file must have a .csv or .txt extension, otherwise the upload is refused with "Your file must have an extension of .txt or .csv". The upload is also refused if a log with the same name already exists, so delete the existing log first or rename the new one.

CAN Data Log Replayer

Control the replay

While a replay plays, the position slider moves through the log. You can drag the slider at any time, including during playback. If you release the handle during playback, the replay jumps to that point and continues playing. If the replay is paused or stopped, the handle sets the position that Play resumes from. Pause suspends the replay, and Play resumes it. Stop ends the replay, and Loop replays the log continuously. The trashcan icon deletes a log file from the list, which is separate from controlling a replay.

If nothing happens

Only a CAN message log recorded by a File or SFTP logger can be replayed, so an uploaded file of another kind does not play. If the CAN LOG REPLAY entry is missing from the side menu, the signed-in user lacks the Replay CAN logs permission. If the replay runs but the dashboards stay empty, no component in the active profile listens to the replayed CAN IDs. Load the profile that the log was recorded against. Recorded tag values are replayed separately with TAG LOG REPLAY, described in Replay a tag log.

To check a Custom Component against its CAN database (DBC) file with recorded messages, refer to Using a Custom Component.