[core] Don't try to monitor zipped files

[dayshah]

Why are these changes needed?

Some users may implement their own log rotation on autoscaler event files. If zipping the files during rotation, the event agent will still try to read zipped files and raise an exception causing that file monitor to fail. We try to open the files every 0.1 seconds. We only need to look for new events in .log files that are actively being written to.

This pr prevents opening and looking for changes in zipped files. There will be no further changes in these files, so we don't need to monitor them. This can lead to exceptions like

Exception: Read event file failed: /tmp/ray/session_2025-04-30_09-40-39_975641_2270/logs/events/event_AUTOSCALER.log.2.gz
    raise Exception(f"Read event file failed: {file}") from e
File "/home/ray/anaconda3/lib/python3.12/site-packages/ray/dashboard/modules/event/event_utils.py", line 176, in 
_read_monitor_file

Related issue number

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[israbbani]

Lol so many questions:

• How was this discovered?
• Which component is monitoring these files and why?

[dayshah]

Lol so many questions:

• How was this discovered?
• Which component is monitoring these files and why?

added some extra context, discovered by looking at some user dashboard logs from a long running cluster

[jjyao]

As discussed, let's also mention the long term fix here.

[dayshah]

As discussed, let's also mention the long term fix here.

@edoakes @israbbani @MengjinYan Long term we'll kill this event agent / head entirely with the new observability stack, and Ray will stop writing events to files. Any events should follow a similar path to the new task events. An rpc with events should be sent to the gcs from the component emitting the events and the events will eventually get persisted in some storage, users can plug-in their own storage to persist.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had any activity for 14 days. It will be closed in another 14 days if no further activity occurs. Thank you for your contributions.

You can always ask for help on our discussion forum or Ray's public slack channel.

If you'd like to keep this open, just leave any comment, and the stale label will be removed.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had any activity for 14 days. It will be closed in another 14 days if no further activity occurs. Thank you for your contributions.

You can always ask for help on our discussion forum or Ray's public slack channel.

If you'd like to keep this open, just leave any comment, and the stale label will be removed.

[dayshah]

@edoakes