rrdcgi - Online in the Cloud

PROGRAM:

NAME

rrdcgi - Create web pages containing RRD graphs based on templates

SYNOPSIS

"#!/path/to/"rrdcgi [--filter|-f]

DESCRIPTION

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 3 steps. In each step it looks only for a
subset of tags. This allows nesting of tags.

The argument parser uses the same semantics as you are used from your C-shell.

--filter|-f
Assume that rrdcgi is run as a filter and not as a cgi.

Keywords
RRD::CV name
Inserts the CGI variable of the given name.

RRD::CV::QUOTE name
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 to be one argument.

RRD::CV::PATH name
Inserts the CGI variable of the given name, quotes it and makes sure it starts
neither with a '/' nor contains '..'. This is to make sure that no problematic
pathnames can be introduced through the CGI interface.

RRD::GETENV variable
Get the value of an environment variable.

<RRD::GETENV REMOTE_USER>

might give you the name of the remote user given you are using some sort of access
control on the directory.

RRD::GOODFOR seconds
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 header.

RRD::INCLUDE filename
Include the contents of the specified file into the page returned from the cgi.

RRD::SETENV variable value
If you want to present your graphs in another time zone than your own, you could
use

<RRD::SETENV TZ UTC>

to make sure everything is presented in Universal Time. Note that the values
permitted to TZ depend on your OS.

RRD::SETVAR variable value
Analog to SETENV but for local variables.

RRD::GETVAR variable
Analog to GETENV but for local variables.

RRD::TIME::LAST rrd-file strftime-format
This gets replaced by the last modification time of the selected RRD. The time is
strftime-formatted with the string specified in the second argument.

RRD::TIME::NOW strftime-format
This gets replaced by the current time of day. The time is strftime-formatted with
the string specified in the argument.

Note that if you return : (colons) from your strftime format you may have to
escape them using \ if the time is to be used as an argument to a GRAPH command.

RRD::TIME::STRFTIME START|END start-spec end-spec strftime-format
This gets replaced by a strftime-formatted time using the format strftime-format
on either start-spec or end-spec depending on whether START or END is specified.
Both start-spec and end-spec must be supplied as either could be relative to the
other. This is intended to allow pretty titles on graphs with times that are
easier for non RRDtool folks to figure out than "-2weeks".

Note that again, if you return : (colon) from your strftime format, you may have
to escape them using \ if the time is to be used as an argument to a GRAPH
command.

RRD::GRAPH rrdgraph arguments
This tag creates the RRD graph defined by its argument and then is 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 PNG file argument will get dropped.

RRD::PRINT number
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.

RRD::INTERNAL <var>
This tag gets replaced by an internal var. Currently these vars are known:
VERSION, COMPILETIME. These vars represent the compiled-in values.

EXAMPLE 1

The example below creates a web page with a single RRD graph.

#!/usr/local/bin/rrdcgi
<HTML>
<HEAD><TITLE>RRDCGI Demo</TITLE></HEAD>
<BODY>
<H1>RRDCGI Example Page</H1>
<P>
<RRD::GRAPH demo.png --lazy --title="Temperatures"
DEF:cel=demo.rrd:exhaust:AVERAGE
LINE2:cel#00a000:"D. Celsius">

</P>
</BODY>
</HTML>

EXAMPLE 2

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 as 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>.png --lazy
--title "Temperatures for "<RRD::CV::QUOTE RRD_NAME>
DEF:cel=<RRD::CV::PATH RRD_NAME>.rrd:exhaust:AVERAGE
LINE2:cel#00a000:"D. Celsius">

</P>
</BODY>
</HTML>

EXAMPLE 3

This example shows how to handle the case where the RRD, graphs and cgi-bins are separate
directories

#!/.../bin/rrdcgi
<HTML>
<HEAD><TITLE>RRDCGI Demo</TITLE></HEAD>
<BODY>
<H1>RRDCGI test Page</H1>
<RRD::GRAPH
/.../web/pngs/testhvt.png
--imginfo '<IMG SRC=/.../pngs/%s WIDTH=%lu HEIGHT=%lu >'
--lazy --start -1d --end now
DEF:http_src=/.../rrds/test.rrd:http_src:AVERAGE
AREA:http_src#00ff00:http_src
>
</BODY>
</HTML>

Note 1: Replace /.../ with the relevant directories

Note 2: The SRC=/.../pngs should be paths from the view of the webserver/browser

Use rrdcgi online using onworks.net services