COLLECTD_FACTER_INTERVAL env to specify interval

facter can be a relativly expensive command
to run so reducing the collectd frequence
is very useful.

Unfortuantly collectd python does
not support this per python plugin.
[#717](collectd/collectd#717)

If set to a number of seconds this will be interval
for collectd_python.

README.rst

@@ -0,0 +1,7 @@
+Environment Variables.
+----------------------
+
+-  ``COLLECTD_FACTER_INTERVAL`` If set to a number
+   of seconds collectd_facter will read and publish data
+   at this interval. Work around for
+   https://github.com/collectd/collectd/issues/717

collectd_facter/__init__.py

@@ -103,6 +103,10 @@ def shutdown():
 # Register Callbacks
 # -----------------------------------------------------------------------------
 collectd.register_config(config)
-collectd.register_read(read)
+try:
+  interval  = int(os.environ['COLLECTD_FACTER_INTERVAL'])
+  collectd.register_read(read,interval)
+except KeyError, e:
+  collectd.register_read(read)
 collectd.register_shutdown(shutdown)