kumomta/simple_policy.lua

-- Called to validate the helo and/or ehlo domain
on("smtp_server_ehlo", function(domain)
  print("ehlo domain is", domain)
end)

-- Called to validate the sender
on("smtp_server_mail_from", function(sender)
  print("sender", tostring(sender))
end)

-- Called to validate a recipient
on("smtp_server_mail_rcpt_to", function(rcpt)
  print("rcpt", tostring(rcpt))
end)

-- Called once the body has been received
on("smtp_server_message_received", function(msg)
  print("id", msg:id(), "sender", tostring(msg:sender()))

  -- set/get metadata fields
  msg:set_meta("foo", "bar")
  print("meta foo is", msg:get_meta("foo"))
end)