=================
Logging subsystem
=================

There are three types of message tracing that may be enabled in the OPC-UA server:

  * Debugging messages
  * Information messages
  * Error messages


All information is by default sent to the `trace function <../doc/?url=lua.html#_G_trace>`_. You may override the message tracing as follows:

.. code-block:: lua

  local ua = require("opcua.api")
  -- Debug messages
  ua.log.dbg = function(msg)
    print(sock.gettime(), "[DBG] ", msg)
  end

  -- Information messages
  ua.log.inf = function(msg)
    print(sock.gettime(), "[INF]", msg)
  end

  -- Errors highlighted with red color on POSIX terminals
  ua.log.err = function(msg)
    print(sock.gettime(), "\27[31m[ERR]\27[39m", msg)
  end