rrds(1)
NAME
RRDs - Access rrdtool as a shared module
SYNOPSIS
use RRDs; RRDs::error RRDs::last ... RRDs::info ... RRDs::create ... RRDs::update ... RRDs::graph ... RRDs::fetch ... RRDs::tune ... RRDs::times(start, end)
DESCRIPTION
Calling Sequence
- This module accesses rrdtool functionality directly from
within perl. The arguments to the functions listed in the
SYNOPSIS are explained in the regular rrdtool documenta
tion. The commandline call - rrdtool update mydemo.rrd --template in:out N:12:13
- gets turned into
RRDs::update ("mydemo.rrd", "--template", "in:out",- "N:12:13");
- Note that
--template=in:out- is also valid.
- The RRDs::times function takes two parameters: a "start"
and "end" time. These should be specified in the AT-STYLE TIME SPECIFICATION format used by rrdtool. See the rrd fetch documentation for a detailed explanation on how to
specify time. - Error Handling
- The RRD functions will not abort your program even when
they can not make sense out of the arguments you fed them. - The function RRDs::error should be called to get the error
status after each function call. If RRDs::error does not
return anything then the previous function has completed
its task successfully.
use RRDs;
RRDs::update ("mydemo.rrd","N:12:13");
my $ERR=RRDs::error;
die "ERROR while updating mydemo.rrd: $ERR0 if $ERR;- Return Values
- The functions RRDs::last, RRDs::graph, RRDs::info,
RRDs::fetch and RRDs::times return their findings. - RRDs::last returns a single INTEGER representing the last update time.
$lastupdate = RRDs::last ...- RRDs::graph returns an pointer to an ARRAY containing the
x-size and y-size of the created gif and results of the
PRINT arguments.
($averages,$xsize,$ysize) = RRDs::graph ...
print "Gifsize: ${xsize}x${ysize}0;
print "Averages: ", (join ", ", @$averages);- RRDs::info returns a pointer to a hash. The keys of the
hash represent the property names of the rrd and the val
ues of the hash are the values of the properties.
$hash = RRDs::info "example.rrd";
foreach my $key (keys %$hash){print "$key = $$hash{$key}0;- }
- RRDs::fetch is the most complex of the pack regarding
return values. There are 4 values. Two normal integers, a
pointer to an array and a pointer to a array of pointers.
my ($start,$step,$names,$data) = RRDs::fetch ...
print "Start: ", scalar localtime($start), "- ($start)0;
print "Step size: $step seconds0;
print "DS names: ", join (", ", @$names)."0;
print "Data points: ", $#$data + 1, "0;
print "Data:0;
foreach my $line (@$data) {print " ", scalar localtime($start), " ($start) ";
$start += $step;
foreach my $val (@$line) {printf "%12.1f ", $val;}
print "0; - }
- RRDs::times returns two integers which are the number of
seconds since epoch (1970-01-01) for the supplied "start"
and "end" arguments, respectively. - See the examples directory for more ways to use this
extension.
NOTE
- If you are manipulating the TZ variable you should also
call the posixs function tzset to initialize all internal
state of the library for properly operating in the time
zone of your choice. - use POSIX qw(tzset);
$ENV{TZ} = 'CET';
POSIX::tzset();
AUTHOR
- Tobias Oetiker <oetiker@ee.ethz.ch>