RRDCGI(1) rrdtool RRDCGI(1)
rrdcgi - Create web pages containing RRD graphs based on templates
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
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
Assume that rrdcgi is run as a filter and not as a cgi.
Inserts the CGI variable of the given 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.
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.
Get the value of an environment variable.
might give you the name of the remote user given you are using
some sort of access control on the directory.
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
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.
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.
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
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 tag gets replaced by an internal var. Currently these vars
are known: VERSION, COMPILETIME. These vars represent the
The example below creates a web page with a single RRD graph.
<H1>RRDCGI Example Page</H1>
<RRD::GRAPH demo.png --lazy --title="Temperatures"
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.
<H1>RRDCGI Example Page for <RRD::CV RRD_NAME></H1>
<FORM><INPUT NAME=RRD_NAME TYPE=RADIO VALUE=roomA> Room A,
<INPUT NAME=RRD_NAME TYPE=RADIO VALUE=roomB> Room B.
<RRD::GRAPH <RRD::CV::PATH RRD_NAME>.png --lazy
--title "Temperatures for "<RRD::CV::QUOTE RRD_NAME>
This example shows how to handle the case where the RRD, graphs and
cgi-bins are separate directories
<H1>RRDCGI test Page</H1>
--imginfo '<IMG SRC=/.../pngs/%s WIDTH=%lu HEIGHT=%lu >'
--lazy --start -1d --end now
Note 1: Replace /.../ with the relevant directories
Note 2: The SRC=/.../pngs should be paths from the view of the
Tobias Oetiker <firstname.lastname@example.org>
1.7.0 2018-02-07 RRDCGI(1)