Entries posted in April 2009

I work with log files a lot.

Most of the logfiles I work with are in a standard format of some kind, and most often they are rotated upon a daily basis. (Examples include syslog, qpsmtpd, and Apache logfiles.)

I wish there were a general purpose way to say "grep time-range pattern logfile".

Right now, for example, I've just deployed some changes upon a cluster of hosts. Now I want to see only messages that refer to a particular area of the codebase only those that occurred after 23:00 - which is when I did the commit/push/pull dance.

I've written a quick hack - tgrep (time-grep) - which allows simple before/equal/after/range grepping :

# show matching lines after 23:00PM
tgrep \>23:00:00 -i subject /var/log/qpsmtpd/qpsmtpd.log

# show matching lines in the interval 23:00PM 23:15PM
tgrep 23:00:00-23:15:00 -i -r subject /var/log/qpsmtpd/

If there is a common way of doing this "properly" then I'd love to be educated, failing that take it if it is useful (moreutils?)

ObFilm: Chasing Amy

Tags: random hacks, tgrep, utilities | 8 comments

I'd forgotten how sexy, useful, and great mod_perl is.

I've recently been struggling with a friend's CGI-based site, and after a minor effort we made it run with Apache::PerlRun:

Apache::PerlRun gives you the benefit of preloaded Perl and its modules. This module's handler emulates the CGI environment, allowing programmers to write scripts that run under CGI or mod_perl without any change

Because the site code wasn't very clean we had to make a lot of changes to get it working under Apache::Registry.

Apache::Registry is the Apache module allowing you to run CGI scripts very fast under mod_perl, by compiling all scripts once and then caching them in memory.

But the payoff is very noticeable - the site is now blazingly fast!

At some point I should write a guide to doing basic things with mod_perl. Mostly I guess the challenge is that you can write toy applications in moments, but to demonstrate how useful it is you need to apply it to something the reader is familiar with. Or demonstrate why the effort is worthwhile, given that it ties you to the Apache + mod_perl platform.

Any links to existing guides, or suggestions on how to approach the guide-writing in a beginner-friendly but still useful fashion are welcome.

(For what its worth I mostly write web applications using CGI::Application & jQuery these days.)

ObFilm: Pretty In Pink

Tags: cgi::application, jquery, mod_perl | 4 comments