Stumped with select->can_readby w1r3d (Initiate)
|on Aug 03, 2012 at 19:05 UTC||Need Help??|
w1r3d has asked for the
wisdom of the Perl Monks concerning the following question:
I've been trying to figure out how select->can_read works, and if it's even what's causing my frustration.
I currently have a cron job that runs nightly on a bunch of machines and sends the results via syslog to a central log server. On the log server, there's a script (script1.pl) that reads the syslog messages file and looks for certain keywords, then copies the messages out to different log files. For this example, I'll call one of those log files sub.log.
There's yet another script (script2.pl) that tails sub.log and all the other logs written by script1.pl, again looking for more specific keywords. If it finds a match, then it writes the message out to another log file (reduced.log).
The problem I'm seeing is that while everything gets successfully copied by script1.pl to sub.log, not everything gets copied to reduced.log - at least not right away.
The way script1.pl works is by doing:
script2.pl, however, works by doing something like:
What ends up happening is that let's say that 15 lines get written to sub.log (I can verify this by tailing it from the terminal) and 5 of those match the keyword I'm looking for, only two of the lines will actually get written to reduced.log (the number "two" is made up, I haven't figured out a pattern yet). If I run a test script to write 15 additional lines to sub.log, now I will get the remaining 3 lines from the previous run in reduced.log, plus *some* from the latest run. So, my reduced.log file is never up to date with the data that's in sub.log, and if for whatever reason the script dies, then I "lose" that data.
At first I thought the problem had to do with the flushing of the buffer so I added autoflush to pretty much all the filehandles, to no avail. It seems as if the select is getting all the data, I'm just not processing it correctly or something :/
Thanks in advance!