How to: View Human-Readable Timestamps in qmail Logs
====================================================

InterWorx uses ``qmail`` to provide SMTP services. ``qmail`` provides logging
in ``/var/log/send`` and ``/var/log/smtp`` for system administrators who would like to see information regarding
the sending and receiving of email. ``qmail`` uses TAI64N timestamps on each line of its
logs. They appear like so:

.. code-block::

   @40000000600db35c0c07e714

The ``tai64nlocal`` command can be used to convert TAI64N 
timestamps to a human-readable format. More information can be found here:
`<http://cr.yp.to/daemontools/tai64nlocal.html>`__. 

This tool is installed by default alongside InterWorx.

.. contents::

To Convert TAI64N Timestamps
----------------------------

This command works by reading lines straight from stdin. In order to use it,
it necessary to pipe the lines to convert into tai64nlocal. A simple example
is:

.. code-block::

   [root@iw7 smtp]# echo @40000000600db35c0c07e714 | tai64nlocal
   2021-01-24 12:50:10.201844500

It may necessary, in the course of system administration, to see these
human-readable timestamps in ``/var/log/smtp/current``. Normally, this log
will appear like so:

.. code-block::

   [root@server ~]# cat /var/log/smtp/current
   @40000000600dab2f0f7636bc tcpserver: status: 0/20
   @40000000600db35c0bcdc05c tcpserver: status: 1/20
   @40000000600db35c0c07e714 tcpserver: pid 7189 from 127.0.0.1
   @40000000600db35c0c07eee4 tcpserver: ok 7189 iw7.com:::ffff:127.0.0.1:25 :::ffff:127.0.0.1::47407
   @40000000600db35c1291f994 tcpserver: end 7189 status 256
   @40000000600db35c12920164 tcpserver: status: 0/20
   @40000000600db55b2aedd094 tcpserver: status: 1/20
   @40000000600db55b2b1814e4 tcpserver: pid 10593 from 127.0.0.1
   @40000000600db55b2b1818cc tcpserver: ok 10593 iw7.com:::ffff:127.0.0.1:25 :::ffff:127.0.0.1::47699
   @40000000600db55b2ec2544c tcpserver: end 10593 status 256

Piping this output into ``tai64nlocal`` allows for the human-readable
timestamps to replace the TAI64N timestamps:

.. code-block::

   [root@server ~]# cat /var/log/smtp/current | tai64nlocal
   2021-01-24 12:15:17.259405500 tcpserver: status: 0/20
   2021-01-24 12:50:10.198033500 tcpserver: status: 1/20
   2021-01-24 12:50:10.201844500 tcpserver: pid 7189 from 127.0.0.1
   2021-01-24 12:50:10.201846500 tcpserver: ok 7189 iw7.com:::ffff:127.0.0.1:25 :::ffff:127.0.0.1::47407
   2021-01-24 12:50:10.311556500 tcpserver: end 7189 status 256
   2021-01-24 12:50:10.311558500 tcpserver: status: 0/20
   2021-01-24 12:58:41.720228500 tcpserver: status: 1/20
   2021-01-24 12:58:41.722998500 tcpserver: pid 10593 from 127.0.0.1
   2021-01-24 12:58:41.722999500 tcpserver: ok 10593 iw7.com:::ffff:127.0.0.1:25 :::ffff:127.0.0.1::47699
   2021-01-24 12:58:41.784487500 tcpserver: end 10593 status 256

Using ``tai64nlocal`` With Other Commands
-----------------------------------------

``tai64nlocal`` can be combined with other commands for greater flexibility.

- To convert timestamps before opening a file in vim:

   .. code-block::

      vim /var/log/send/current | tai64nlocal

- To grep for a specific pattern in a file and return the output with converted timestamps:

   .. code-block::

      grep [pattern] [file] | tai64nlocal