plugin zfs_list: add "ignore_datasets_pattern" configuration

Allow to ignore certain volumes.

plugins/zfs/zfs_list

@@ -1,21 +1,37 @@
 #!/bin/bash
-#
-# Plugin to monitor ZFS Filesystems
-# Author: Adam Michel (elfurbe@furbism.com)
-# Description:
-#  This is an extension of the zfs_fs plugin
-#  modified as a multigraph to graph all zfs
-#  filesystems it can find
-#
-# Tested on Ubuntu-14.04
-#
-# Parameters understood:
-#
-# 	config   (required)
-# 	autoconf (optional - used by munin-config)
-#
 #%# family=auto
 
+: << EOF
+=head1 NAME
+zfs_list - Plugin to monitor ZFS Filesystems
+
+This is an extension of the zfs_fs plugin
+modified as a multigraph to graph all zfs
+filesystems it can find
+
+=head1 CONFIGURATION
+plugin config:
+[zfs_list]
+env.ignore_datasets_pattern <Datasets to ignore; String for grep>
+
+
+=head1 AUTHOR
+=over 4
+=item * Adam Michel (elfurbe@furbism.com)
+=back
+
+
+=head1 MAGIC MARKERS
+=begin comment
+These magic markers are used by munin-node-configure when installing
+munin-node.
+=end comment
+  #%# family=auto
+=cut
+
+EOF
+
+
 . "$MUNIN_LIBDIR/plugins/plugin.sh"
 
 need_multigraph()
@@ -30,8 +46,20 @@ if [ "$1" = "suggest" ]; then
 	exit 0
 fi
 
+# set standard value
+ignore_datasets_pattern=${ignore_datasets_pattern:-}
+
+# set search term, based on if the searh pattern is set
+if [ -n "$ignore_datasets_pattern" ]; then
+  search_term=$(zfs list -Hp -t filesystem,volume | grep -v "$ignore_datasets_pattern" | awk '{print $1}')
+else
+  search_term=$(zfs list -Hp -t filesystem,volume | awk '{print $1}')
+fi
+
+
+
 if [ "$1" = "config" ]; then
-	for i in `zfs list -Hp -t filesystem,volume | awk '{print $1}'`; do
+	for i in $search_term; do
 		values=( $(zfs get -p usedbydataset,usedbychildren,usedbysnapshots,usedbyrefreservation,available,quota $i | awk 'BEGIN {total=0;} { if( NR==1 ) next; } !/quota/ {total=total+$3;} {print $3} END{print total;}') )
 		fsname=$(clean_fieldname $(echo "$i" | sed 's/\//__/g'))
 
@@ -39,7 +67,7 @@ if [ "$1" = "config" ]; then
 graph_title $fsname usage
 graph_order usedbydataset usedbychildren usedbysnapshots usedbyrefreservation available total quota
 graph_args --base 1024 -r -l 0 --vertical-label Bytes --upper-limit ${values[6]}
-graph_info This graph shows how is used a zfs filesystems.
+graph_info This graph shows how a zfs filesystem is used.
 graph_category fs
 graph_period second
 usedbydataset.label UsedByDataset
@@ -75,7 +103,7 @@ EOF
 	exit 0
 fi
 
-for i in `zfs list -Hp -t filesystem,volume | awk '{print $1}'`; do
+for i in $search_term; do
 	values=( $(zfs get -p usedbydataset,usedbychildren,usedbysnapshots,usedbyrefreservation,available,quota $i | awk 'BEGIN {total=0;} { if( NR==1 ) next; } !/quota/ {total=total+$3;} {print $3} END{print total;}') )
 	fsname=$(clean_fieldname $(echo "$i" | sed 's/\//__/g'))