RRDp - Attach RRDtool from within a perl script via a set of pipes;
RRDp::start path to RRDtool executable
RRDp::cmd rrdtool commandline
$answer = RRD::read
$status = RRD::end
$RRDp::user, $RRDp::sys, $RRDp::real, $RRDp::error_mode, $RRDp::error
With this module you can safely communicate with the RRDtool.
After every RRDp::cmd you have to issue an RRDp::read command to get RRDtools answer to your command. The answer is returned as a pointer, in order to speed things up. If the last command did not return any data, RRDp::read will return an undefined variable.
If you import the PERFORMANCE variables into your namespace, you can access RRDtool's internal performance measurements.
pass commands on to RRDtool. Check the RRDtool documentation for more info on the RRDtool commands.
Note: Due to design limitations, RRDp::cmd does not support the
graph - command - use
graphv - instead.
these variables will contain totals of the user time, system time and real time as seen by RRDtool. User time is the time RRDtool is running, System time is the time spend in system calls and real time is the total time RRDtool has been running.
The difference between user + system and real is the time spent waiting for things like the hard disk and new input from the Perl script.
If you set the variable $RRDp::error_mode to the value 'catch' before you run RRDp::read a potential ERROR message will not cause the program to abort but will be returned in this variable. If no error occurs the variable will be empty.
$RRDp::error_mode = 'catch'; RRDp::cmd qw(info file.rrd); print $RRDp::error if $RRDp::error;
use RRDp; RRDp::start "/usr/local/bin/rrdtool"; RRDp::cmd qw(create demo.rrd --step 100 DS:in:GAUGE:100:U:U RRA:AVERAGE:0.5:1:10); $answer = RRDp::read; print $$answer; ($usertime,$systemtime,$realtime) = ($RRDp::user,$RRDp::sys,$RRDp::real);
For more information on how to use RRDtool, check the manpages.
Tobias Oetiker <email@example.com>