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Changes the filtering configuration for the diagnostic log.

KumoMTA uses the tracing-subscriber Rust crate to provide diagnostic logging. This can be configured via the KUMOD_LOG environment to set the logging for the process when it first starts up, but can also be adjusted via your policy file by calling kumo.set_diagnostic_log_filter if you wish.

The default log filter that is set at startup is kumod=info which causes all informational logging from the kumod crate (the main KumoMTA server process) to be logged.

If you want more verbose diagnostics, you might consider changing it from inside your init event handler:

kumo.on('init', function()
  kumo.set_diagnostic_log_filter 'kumod=debug'

The filter syntax is quite powerful, allowing you set different levels for different crates. The full set of filter directives are explained here.