Merge pull request #781 from sumpfralle/zfspool-fieldnames

[zpool_iostat] Code cleanup and fix for fieldname issue with leading digit

plugins/zfs/zpool_iostat

@@ -1,48 +1,128 @@
-#!/bin/bash
+#!/bin/sh
+# -*- sh -*-
 
-if [ "$1" = "autoconf" ]; then
-                echo yes
-                exit 0
+set -eu
+
+: <<=cut
+
+=head1 NAME
+
+zpool_iostat - Plugin to monitor transfer statistics of ZFS pools
+
+=head1 APPLICABLE SYSTEMS
+
+All systems with "zpool" installed.
+
+=head1 CONFIGURATION
+
+No configuration is required.
+
+=head1 INTERPRETATION
+
+This plugin shows a graph with read (positive) and write (negative) values
+for the IO transfer of each pool.
+
+=head1 MAGIC MARKERS
+
+  #%# family=auto
+  #%# capabilities=autoconf
+
+=head1 AUTHOR
+
+tsaavik <github@hellspark.com>
+Peter Doherty <peterd@acranox.org>
+Lars Kruse <devel@sumpfralle.de>
+
+=head1 LICENSE
+
+GPLv2
+
+=cut
+
+
+# shellcheck source=/usr/share/munin/plugins/plugin.sh
+. "$MUNIN_LIBDIR/plugins/plugin.sh"
+
+
+ZPOOL_BIN=/sbin/zpool
+ACTION="${1:-}"
+
+
+if [ "$ACTION" = "autoconf" ]; then
+	if [ -x "$ZPOOL_BIN" ]; then
+		echo yes
+	else
+		echo "no (missing executable '$ZPOOL_BIN')"
+	fi
+	exit 0
 fi
 
-zlines=`/sbin/zpool iostat -v| wc -l|sed 's/ //g'`
-ztail=`echo "-"$zlines`
-ztmp=/var/run/munin/zpool_iostat
-zdata=`/sbin/zpool iostat -v 1 1| tail $ztail > $ztmp`
-zlist=`cat $ztmp|gawk '/alloc/ {next}; /avail/ {next}; /raid/ {next}; /mirror/ {next}; { if ( $4 >=0 ) print $1}'`
-zname=`cat $ztmp|gawk '/alloc/ {next}; /avail/ {next}; /raid/ {next}; /mirror/ {next}; { if ( $4 >=0 ) print $1}'|gawk '{gsub("[^a-zA-Z0-9_]", "_", $1); print}'`
-zorder=`for o in $zname; do echo $o'_read '; echo $o'_write '; done`
+zlines=$("$ZPOOL_BIN" iostat -v | wc -l | sed 's/ //g')
+iostats=$("$ZPOOL_BIN" iostat -v 1 1 | tail "-$zlines")
+zlist=$(echo "$iostats" \
+	| gawk '/alloc/ {next}; /avail/ {next}; /raid/ {next}; /mirror/ {next};
+		{ if ( $4 >=0 ) print $1}' \
+	| tr ' ' '\n')
 
-if [ "$1" = "config" ]; then
-        echo 'graph_title zpool iostat'
-        echo 'graph_args --base 1000 -l 0'
-        echo 'graph_vlabel write - read KBytes/s'
-        echo 'graph_category fs'
-        echo 'graph_scale no'
-        echo 'graph_info This graph shows zpool iostat'
-	echo 'graph_order '$zorder
-	echo $zlist | tr ' ' '\n' | while read i; do
-                case $i in
-                *) name=`echo $i | gawk '{ gsub("[^a-zA-Z0-9_]", "_", $1); print }'` ;;
-                esac
-                echo $name'_read.label '$i
-		echo $name'_read.type GAUGE'
-		echo $name'_read.graph no'
-		echo $name'_write.label '$i
-		echo $name'_write.type GAUGE'
-		echo $name'_write.negative '$name'_read'
-        done
-        exit 0
+# Parse the n'th column of the iostat output for a given pool or disk as a
+# number (interpreting K and M suffixes).
+get_device_iostat_column() {
+	local device_label="$1"
+	local stat_column="$2"
+	# convert all numeric values into kB
+	echo "$iostats" \
+		| gawk '{ if ($1 == "'"$device_label"'")
+				print $'"$stat_column"'; }' \
+		| gawk '/M/ {print strtonum($1)*1000};
+			/K/ {print strtonum($1)};
+			/[0-9]$/ {print int($1)/1000}'
+}
+
+
+get_device_fieldname() {
+	local device_id="$1"
+	# Backwards compatibility (until 2016): keep the unprefixed pool name
+	# for the fieldname, except for pool names starting with digits.
+	if echo "$device_id" | grep -q "^[0-9]"; then
+		clean_fieldname "_$device_id"
+	else
+		clean_fieldname "$device_id"
+	fi
+}
+
+
+if [ "$ACTION" = "config" ]; then
+	echo 'graph_title zpool iostat'
+	echo 'graph_args --base 1000 -l 0'
+	echo 'graph_vlabel write (-) / read (+) KBytes/s'
+	echo 'graph_category disk'
+	echo 'graph_scale no'
+	echo 'graph_info This graph shows zpool iostat'
+	# Assemble the "graph_order" as a sorted list of read/write pairs for
+	# each device.
+	printf "graph_order"
+	echo "$zlist" | while read -r device_id; do
+		fieldname="$(get_device_fieldname "$device_id")"
+		printf " %s_read %s_write" "$fieldname" "$fieldname"
+	done
+	# finalize the 'graph_order' with a newline
+	echo
+	# output all fields: write as negative numbers and read as positive
+	echo "$zlist" | while read -r device_id; do
+		fieldname="$(get_device_fieldname "$device_id")"
+		echo "${fieldname}_read.label $device_id"
+		echo "${fieldname}_read.type GAUGE"
+		echo "${fieldname}_read.graph no"
+		echo "${fieldname}_write.label $device_id"
+		echo "${fieldname}_write.type GAUGE"
+		echo "${fieldname}_write.negative ${fieldname}_read"
+	done
+	exit 0
 fi
-echo $zlist | tr ' ' '\n' | while read iz; do
-	zlabel=`echo $iz|gawk '{print $1}'`
-	case $iz in
-	*) name=`echo $iz | gawk '{ gsub("[^a-zA-Z0-9_]", "_", $1); print $1 }'` ;;
-	esac
-	echo -n $name'_read.value '
-	gawk '{ if ($1 == "'"$zlabel"'") print $6; }' "$ztmp"|gawk '/M/ {print strtonum($1)*1000}; /K/ {print strtonum($1)}; /[0-9]$/ {print int($1)/1000}'
-	echo -n $name'_write.value '
-	gawk '{ if ($1 == "'"$zlabel"'") print $7; }' "$ztmp"|gawk '/M/ {print strtonum($1)*1000}; /K/ {print strtonum($1)}; /[0-9]$/ {print int($1)/1000}'
+
+
+echo "$zlist" | while read -r device_id; do
+	fieldname="$(get_device_fieldname "$device_id")"
+	echo "${fieldname}_read.value $(get_device_iostat_column "$device_id" 6)"
+	echo "${fieldname}_write.value $(get_device_iostat_column "$device_id" 7)"
 done
-
-rm $ztmp; touch $ztmp