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kumo.log_warn(ARGS)

Since: Version 2025.03.19-1d3f1f67

The functionality described in this section requires version 2025.03.19-1d3f1f67 of KumoMTA, or a more recent version.

Logs the series of ARGS to the diagnostic log at WARN level. This works similarly to the print function except that it is routed via the diagnostic logging system, which might be set to filter out the event via the set_diagnostic_log_filter.

The purpose of this function is to log meaningful information from your policy scripts for diagnostic purposes.

-- I am a file named unix.lua
-- The next line is line number 3
kumo.log_warn('Logging something', true, false, 42, { 1, 2, 3 })

Will produce something like this in your diagnostic log:

2025-03-07T00:08:20.071516Z WARN  main lua: ./unix.lua:3: Logging something true false 42 table: 0x7199e11bda40

The main string there is the thread name. You can see that the calling source file and line number are automatically included in the diagnostic record. The arguments are converted to strings via the equivalent of the lua tostring() function and output as part of the diagnostic.