Log rotation in Mac OSX
Clark Wilkins
2022.03.19
<p>I have recently started exploring log rotation to better handle some of the Amazon EC2 servers I am using. As part of the learning project, I wanted to do some log rotation in my sandbox environment, where I have some Node/Express APIs doing a <u>lot</u> of logging.</p>

<p>I was surprised, at first, to find there is no <tt>logrotate</tt> binary, but a bit of investigation turned valuable links <a href = "https://serverfault.com/questions/352942/equivalent-of-logrotate-on-osx" target = "_blank">here</a> and <a href = "https://www.real-world-systems.com/docs/newsyslog.1.html" target = "_blank">here</a>.</p>

<p>For my sandbox, I need to rotate logfiles in a local directory, triggered when the file size reaches 100KB, keeping the last two archived logs, running at midnight. This is what it looks like:</p>

<tt>sh-3.2# cat /private/etc/newsyslog.d/clark.conf
# logfilename          				[owner:group]   mode 	count 	size 	when<br />  
/Users/clark/logs/messagine-api-errors.log      clark:staff     644     2       100	$D0<br />
/Users/clark/logs/messagine-api-errors.log	clark:staff	644	2	100	$D0<br />
/Users/clark/logs/messagine-api-output.log      clark:staff     644     2       100	$D0<br />
/Users/clark/logs/messagine-react-errors.log    clark:staff     644     2       100	$D0<br />
/Users/clark/logs/messagine-react-output.log    clark:staff     644     2       100	$D0<br />
/Users/clark/logs/simplexable-api-errors.log    clark:staff     644     2       100	$D0<br />
/Users/clark/logs/simplexable-api-output.log    clark:staff     644     2       100	$D0<br />
/Users/clark/logs/topical-api-errors.log        clark:staff     644     2       100	$D0<br />
/Users/clark/logs/topical-api-output.log        clark:staff     644     2       100	$D0<br />
/Users/clark/logs/topical-react-errors.log      clark:staff     644     2       100	$D0<br />
/Users/clark/logs/topical-react-output.log      clark:staff     644     2       100	$D0</tt>

<p>Once this is setup, there's nothing more to do. Thanks to the sources cited above.</p>