munin-cgi-graph

DESCRIPTION

The munin-cgi-graph program is intended to be run from a web server. It can either run as CGI, or as FastCGI.

OPTIONS

munin-cgi-graph is controlled using environment variables. See environment variables PATH_INFO and QUERY_STRING.

Note: The munin-cgi-graph script may be called with the command line options of munin-graph. However, the existence of this should not be relied upon.

ENVIRONMENT VARIABLES

The following environment variables are used to control the output of munin-cgi-graph:

PATH_INFO

This is the remaining part of the URI, after the path to the munin-cgi-graph script has been removed.

The group, host, service and timeperiod values are extracted from this variable. The group may be nested.

CGI_DEBUG

If this variable is set, debug information is logged to STDERR, and to /var/log/munin/munin-cgi-graph.log

QUERY_STRING

A list of key=value parameters to control munin-cgi-graph. If QUERY_STRING is set, even to an empty value, a no_cache header is returned.

HTTP_CACHE_CONTROL

If this variable is set, and includes the string “no_cache”, a no_cache header is returned.

HTTP_IF_MODIFIED_SINCE

Returns 304 if the graph is not changed since the timestamp in the HTTP_IF_MODIFIED_SINCE variable.

EXAMPLES

When given an URI like the following:

http://munin/munin-cgi/munin-cgi-graph/example.org/client.example.org/cpu-week.png

munin-cgi-graph will be called with the following environment:

PATH_INFO=/example.org/client.example.org/cpu-week.png

To verify that munin is indeed graphing as it should, you can use the following command line:

sudo -u www-data \
PATH_INFO=/example.org/client.example.org/irqstats-day.png \
/usr/lib/munin/cgi/munin-cgi-graph | less

The “less” is strictly not needed, but is recommended since munin-cgi-graph will output binary data to your terminal.

You can add the CGI_DEBUG variable, to get more log information. Content and debug information is logged to STDOUT and STDERR, respectively. If you only want to see the debug information, and not the HTTP headers or the content, you can redirect the file descriptors:

sudo -u www-data \
CGI_DEBUG=yes \
PATH_INFO=/example.org/client.example.org/irqstats-day.png \
/usr/lib/munin/cgi/munin-cgi-graph 2>&1 >/dev/null | less

SEE ALSO

See munin for an overview over munin.