Nigel McNie

This has always bugged me (scroll right to see the whole thing):

[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84] [WAR] 7d (lib/web.php:916) Undefined variable: message, referer: http://mahara-test/admin/extensions/test.php?
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84] Call stack (most recent first):, referer: http://mahara-test/admin/extensions/test.php?
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84]   * log_message("Undefined variable: message", 8, true, true, "/home/nigel/src/mahara-test/htdocs/lib/web.php", 916) at /home/nigel/src/mahara-test/htdocs/lib/errors.php:446, referer: http://mahara-test/admin/extensions/test.php?
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84]   * error(8, "Undefined variable: message", "/home/nigel/src/mahara-test/htdocs/lib/web.php", 916, array(size 2)) at /home/nigel/src/mahara-test/htdocs/lib/web.php:916, referer: http://mahara-test/admin/extensions/test.php?
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84]   * json_reply(false) at /home/nigel/src/mahara-test/htdocs/admin/extensions/test.json.php:22, referer: http://mahara-test/admin/extensions/test.php?
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84] , referer: http://mahara-test/admin/extensions/test.php?

I like using log files to display messages instead of the screen, but somewhere along the way somebody decided that the 'referer' (sic) was needed in the logs too, and that makes them totally unreadable.

Here's my fix, when tailing a log file:

nigel@mahara-test:~$ sudo tail -f /var/log/apache2/mahara-test.error.log | perl -pe 's/, referer:.*//'

And, instantly:

[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84] [WAR] 7d (lib/web.php:916) Undefined variable: message
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84] Call stack (most recent first):
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84]   * log_message("Undefined variable: message", 8, true, true, "/home/nigel/src/mahara-test/htdocs/lib/web.php", 916) at /home/nigel/src/mahara-test/htdocs/lib/errors.php:446
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84]   * error(8, "Undefined variable: message", "/home/nigel/src/mahara-test/htdocs/lib/web.php", 916, array(size 2)) at /home/nigel/src/mahara-test/htdocs/lib/web.php:916
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84]   * json_reply(false) at /home/nigel/src/mahara-test/htdocs/admin/extensions/test.json.php:22
[Tue Apr 20 01:06:47 2010] [error] [client 192.168.5.84]

Much better! But we can do better again:

nigel@mahara-test:~$ sudo tail -f /var/log/apache2/mahara-test.error.log | perl -pe 's/\[error\]\s+\[client.*?\]\s+//; s/, referer:.*//'

And we end up with:

[Tue Apr 20 01:06:47 2010] [WAR] 7d (lib/web.php:916) Undefined variable: message
[Tue Apr 20 01:06:47 2010] Call stack (most recent first):
[Tue Apr 20 01:06:47 2010]   * log_message("Undefined variable: message", 8, true, true, "/home/nigel/src/mahara-test/htdocs/lib/web.php", 916) at /home/nigel/src/mahara-test/htdocs/lib/errors.php:446
[Tue Apr 20 01:06:47 2010]   * error(8, "Undefined variable: message", "/home/nigel/src/mahara-test/htdocs/lib/web.php", 916, array(size 2)) at /home/nigel/src/mahara-test/htdocs/lib/web.php:916
[Tue Apr 20 01:06:47 2010]   * json_reply(false) at /home/nigel/src/mahara-test/htdocs/admin/extensions/test.json.php:22
[Tue Apr 20 01:06:47 2010]

Hooray! Readable PHP log files.

You don't want to have to remember to type all of that, so for best results, put it in a script, chmod +x and you have:

nigel@mahara-test:~$ sudo tail -f /var/log/apache2/mahara-test.error.log | phptail

You could even combine it with Monkeytail to make viewing the logs even easier ;).

I've trawled through the PHP codebase looking for where it adds the referer in a vain attempt to change it, or provide a patch to make it a configuration option. Sadly, I never found it. If anyone finds out, please let me know!

Thanks to Martyn for the original idea, and assisting with the arcane perl stuff.

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