RRDCGI(1)                            rrdtool                           RRDCGI(1)

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  strf‐
             time-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 ar‐
             gument 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 eas‐
             ier 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  regen‐
             erated 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  any  PRINT  arguments,
             then you can access their output with this tag. The number argument
             refers  to  the  number  of the PRINT argument. The 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 web‐
     server/browser

AUTHOR
     Tobias Oetiker <tobi@oetiker.ch>

1.10.0                             2026-05-25                          RRDCGI(1)
