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RRDp(3) User Contributed Perl Documentation RRDp(3)
NAME
RRDp - Attach RRDtool from within a perl script via a set of pipes;
SYNOPSIS
use RRDp
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
DESCRIPTION
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.
use RRDp
Load the RRDp::pipe module.
RRDp::start path to RRDtool executable
start RRDtool. The argument must be the path to the RRDtool executable
RRDp::cmd rrdtool commandline
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.
$answer = RRDp::read
read RRDtool's response to your command. Note that the $answer variable will only
contain a pointer to the returned data. The reason for this is, that RRDtool can
potentially return quite excessive amounts of data and we don't want to copy this
around in memory. So when you want to access the contents of $answer you have to
use $$answer which dereferences the variable.
$status = RRDp::end
terminates RRDtool and returns RRDtool's status ...
$RRDp::user, $RRDp::sys, $RRDp::real
these variables will contain totals of the user time, system time and real time as
seen by RRDtool. User time is the time RRDtool is running, System time is the
time spend in system calls and real time is the total time RRDtool has been
running.
The difference between user + system and real is the time spent waiting for things
like the hard disk and new input from the Perl script.
$RRDp::error_mode and $RRDp::error
If you set the variable $RRDp::error_mode to the value 'catch' before you run
RRDp::read a potential ERROR message will not cause the program to abort but will
be returned in this variable. If no error occurs the variable will be empty.
$RRDp::error_mode = 'catch';
RRDp::cmd qw(info file.rrd);
print $RRDp::error if $RRDp::error;
EXAMPLE
use RRDp;
RRDp::start "/usr/local/bin/rrdtool";
RRDp::cmd qw(create demo.rrd --step 100
DS:in:GAUGE:100:U:U
RRA:AVERAGE:0.5:1:10);
$answer = RRDp::read;
print $$answer;
($usertime,$systemtime,$realtime) = ($RRDp::user,$RRDp::sys,$RRDp::real);
SEE ALSO
For more information on how to use RRDtool, check the manpages.
AUTHOR
Tobias Oetiker <tobi AT oetiker.ch>
perl v5.16.3 2015-11-20 RRDp(3)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2024-11-21 08:10 @3.145.103.169 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)