rrdcgi (1)

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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 < tags. rrdcgi will interpret and act according to these tags. In the end it will printout a web page including the necessary 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 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 is then used to select which 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 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

AUTHOR

Tobias Oetiker <tobi@oetiker.ch>