need_multigraph prevents plugins from being run manually

[robe]

Similar to #810, a call to need_multigraph will prevent a manual execution of the plugin.

Please provide an additional check which verifies if the plugin is being run from a munin environment in the first place.

I used this as a workaround in the meanwhile:

need_multigraph() if ( $ENV{'MUNIN_VERSION'} );

[janl]

Please use munin-run to execute plugins. It sets up the environment correctly.