RRD::CGI::Image - accept CGI-style rrdgraph args to build and print image
This is development code - the API may change!
use RRD::CGI::Image;
use CGI qw[Vars header];
my $image = RRD::CGI::Image->new(
rrd_base => '/var/rrd',
error_img => '/var/www/.../path/to/graphing_error.png',
);
print header( 'image/png' );
$image->print_graph( Vars() );
Behaves like any other new(), really.
The graph will be sent to the location specified by output_file(); STDOUT by default.
In addition to the regular rrdgraph options, you can also add a tz=timezone param which will render the graph in the given timezone.
The key-value pairs need a little translation to get them successfully passed through the URL. Your URL or CGI library will probably handle most of this automatically. Here's the full examplanation.
Let's convert a fairly standard set of args for RRDs::graph() to GET-style CGI params, starting with:
RRDs::graph(
'/path/to/output/file.png',
'--start' => '-1d',
'--end' => 'now',
'--height' => 200,
'--width' => 600,
'--imgformat' => 'PNG',
'--lower-limit' => 0,
'--title' => 'This is a title',
'--vertical-label' => 'bps',
'DEF:ds0' => '/var/rrd/router/data/router.example.com/gigabitethernet101.rrd:ds0:MAX',
'DEF:ds1' => '/var/rrd/router/data/router.example.com/gigabitethernet101.rrd:ds1:MAX',
'CDEF:in:ds0,8,*', # convert bytes to bits
'CDEF:out:ds1,8,*',
'LINE1:in#33ee33:Input',
'LINE1:out#0000ff:Output',
);
First, completely drop the first argument. We don't need an output filename anymore - that's handled by output_file() instead.
Next, change the Perl hash-style key-value params to from key > value to CGI-style: key=value;
Next, delete the first half of the path - the rrd_base() - from your DEF statements. That will change the DEF lines to:
'DEF:ds0' => 'router.example.com/gigabitethernet101.rrd:ds0:MAX',
'DEF:ds1' => 'router.example.com/gigabitethernet101.rrd:ds1:MAX',
Finally, make sure your params are encoded so they pass through the CGI interface. URI::Escape::uri_escape() will, for example, convert the hashmarks in LINE1 statements from # to %23. Here's what the LINE1 entries should look like after encoding:
'LINE1:in%2333ee33:Input',
'LINE1:out%230000ff:Output',
Many of these will be handled automatically if you're relying on a CGI or URL module to construct the URL for you.
Defaults to STDOUT (-).
Users will be able to specify partial paths to the RRDs beneath this directory in their DEF declarations but they will be sandboxed into this directory. Don't be too permissive - it's a security risk.
Must end with "/".
Check your webserver's logs to see what went wrong.
Pertinent if you have RRDs in different timezones.
Called internally.
Joshua Keroes, <joshua at cpan.org>
Please report any bugs or feature requests to bug-rrd-cgi-image at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=RRD-CGI-Image. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
You can find documentation for this module with the perldoc command.
perldoc RRD::CGI::Image
You can also look for information at:
Copyright 2008 Joshua Keroes, all rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
