rrdcgi is a sort of very limited script interpreter. Its purpose
is to run as a cgi-program and parse a web page template containing special
<RRD:: tags. rrdcgi will interpret and act according to these tags.
In the end it will printout a web page including the necessary CGI headers.
rrdcgi parses the contents of the template in 2 steps. In each step it looks
only for a subset of tags. This allows to nest tags.
The argument parser uses the same semantics as you are used from your c shell.
Inserts the CGI variable of the given name but quotes it, ready for
use as an argument in another RRD:: tag. So even when there are spaces in the
value of the CGI variable it will still be considered as one argument.
Inserts the CGI variable of the given name, quotes it and makes sure
the it starts neither with a '/' nor contains '..'. This is to make
sure that no problematic pathnames can be introduced through the
CGI interface.
Specify the number of seconds this page should remain valid. This will prompt
the rrdcgi to output a Last-Modified, an Expire and if the number of
seconds is negative a Refresh headers.
This tag creates the RRD graph defined in its argument and then gets
replaced by an appropriate <IMG> tag referring to the graph.
The --lazy option in RRD graph can be used to make sure that graphs
are only regenerated when they are out of date. The arguments
to the RRD::GRAPH tag work as described in the rrdgraph manual page.
Use the --lazy option in your RRD::GRAPH tags, to reduce the load
on your server. This option makes sure that graphs are only regenerated when
the old ones are out of date.
If you do not specify your own --imginfo format, the following will
be used:
<IMG SRC="%s" WIDTH="%lu" HEIGHT="%lu">
Note that %s stands for the filename part of the graph generated, all
directories given in the GIF file argument will get dropped.
If the preceding RRD::GRAPH tag contained and PRINT arguments,
then you can access their output with this tag. The number argument refers to the
number of the PRINT argument. This first PRINT has number 0.
This script is slightly more elaborate, it allows you to run it from
a form which sets RRD_NAME. RRD_NAME is then used to select which RRD
you want to use a source for your graph.
#!/usr/local/bin/rrdcgi
<HTML>
<HEAD><TITLE>RRDCGI Demo</TITLE></HEAD>
<BODY>
<H1>RRDCGI Example Page for <RRD::CV RRD_NAME></H1>
<H2>Selection</H2>
<FORM><INPUT NAME=RRD_NAME TYPE=RADIO VALUE=roomA> Room A,
<INPUT NAME=RRD_NAME TYPE=RADIO VALUE=roomB> Room B.
<INPUT TYPE=SUBMIT></FORM>
<H2>Graph</H2>
<P>
<RRD::GRAPH <RRD::CV::PATH RRD_NAME>.gif --lazy
--title "Temperatures for "<RRD::CV::QUOTE RRD_NAME>
DEF:cel=<RRD::CV::PATH RRD_NAME>.rrd:exhaust:AVERAGE
LINE2:cel#00a000:"D. Celsius">