shutdown_logging

kumo.on('shutdown_logging', function() end)

Since: Version 2025.10.06-5ec871ab

The functionality described in this section requires version 2025.10.06-5ec871ab of KumoMTA, or a more recent version.

Called by kumod as part of shutdown, just prior to shutting down all loggers.

The intended use case is for you to be able to close any mpsc queues that you might have defined in your policy, which in turn allows for a more graceful shutdown:

local kumo = require 'kumo'

kumo.on('init', function()
  kumo.spawn_task {
    event_name = 'logger',
    args = {},
  }
end)

kumo.on('logger', function(args)
  local q = kumo.mpsc.define 'queue'
  while true do
    local batch = q:recv_many(100)
    if not batch then
      print 'logger loop done; shutting down'
      return
    end
  end
end)

kumo.on('shutdown_logging', function()
  local q = kumo.mpsc.define 'queue'
  q:close()
end)