User guide / Diagnostics and logging

Levels and startup controls

Development reference · View source

The default records warnings and errors, so a first unexpected failure does not need reproducing, while routine operation writes no high-volume trace.

--log PATH chooses an explicit file.

• Failing to use it is a startup error, because silently writing elsewhere would make the capture misleading.
• A path already owned by another running Runyte process is refused after a two-second handover window. Choose another path, or let the first process exit.

An unwritable default file only degrades logging: editing continues, a persistent host still serves, and the failure appears on stderr, as a notification, and in :service-health. If a file stops accepting writes after startup, editing continues and one warning is kept in :notifications, with the standing failure in :service-health.

Persistent hosts fix verbosity and destination at host startup.

• --serve, --session-restart, and the launch that creates a missing host pass them on.
• Attaching to a running host does not change its logger. -v or --log there reports that the session kept its own configuration.
• Restart to change it:

runyte --session-restart -vv     # the only way to change a running host's logging

A normal restart refuses unsaved work: save first, or decide explicitly on --force. There is no runtime log-level command and no protocol message for logging.