As spotted on the zookeeper-user list from Matt Wise <matt@nextdoor.com>

zk_collectd.sh

#!/bin/bash

# Defaults
PORT=2181
HOSTNAME="${COLLECTD_HOSTNAME:-localhost}"
INTERVAL="${COLLECTD_INTERVAL:-5}"

# Generic function for putting a value out there
put_gauge() {
   NAME=$1
   VAL=$2

   # If the VAL or NAME are empty for some reason, we just drop the stat.
   if [ -z $NAME ] || [ -z $VAL ]; then
       return
   fi

   echo "PUTVAL \"$HOSTNAME/zookeeper/gauge-$NAME\" interval=$INTERVAL N:$VAL"
}

# Generic function for putting a value out there
put_counter() {
   NAME=$1
   VAL=$2
   TYPE="${3:-counter}"
   NOW=`date +%s`

   # If the VAL or NAME are empty for some reason, we just drop the stat.
   if [ -z $NAME ] || [ -z $VAL ]; then
       return
   fi

   echo "PUTVAL \"$HOSTNAME/zookeeper/$TYPE-$NAME\" interval=$INTERVAL $NOW:$VAL"
}

# Gather 'global' server stats from the 'srvr' four-letter word.
get_srvr() {
   RAW_STAT=`echo srvr | nc 127.0.0.1 $PORT`

   # Total server connection count
   put_gauge 'connections' `echo $RAW_STAT | egrep -o 'Connections:\ ([0-9]+)' | awk '{print $2}'`

   # Number of outstanding requests
   put_gauge 'outstanding-requests' `echo $RAW_STAT | egrep -o 'Outstanding:\ ([0-9]+)' | awk '{print $2}'`

   # Total number of zNodes registered on this node
   put_gauge 'nodes' `echo $RAW_STAT | egrep -o 'Node count:\ ([0-9]+)' | awk '{print $3}'`

   # Total number of zNodes registered on this node
   LATENCY=`echo $RAW_STAT | egrep -o 'Latency min\/avg\/max:\ ([0-9]+)/([0-9]+)/([0-9]+)' | awk '{print $3}'`
   put_gauge 'latency-min' `echo $LATENCY | awk -F\/ '{print $1}'`
   put_gauge 'latency-avg' `echo $LATENCY | awk -F\/ '{print $2}'`
   put_gauge 'latency-max' `echo $LATENCY | awk -F\/ '{print $3}'`

   # Packets in and out.
   RECEIVED=`echo $RAW_STAT | egrep -o 'Received:\ ([0-9]+)' | awk '{print $2}'`
   SENT=`echo $RAW_STAT | egrep -o 'Sent:\ ([0-9]+)' | awk '{print $2}'`
   put_counter 'traffic' "$RECEIVED:$SENT" 'if_packets'
}

# Gather stats on the total number of 'watches' established
get_wchs() {
   RAW_STAT=`echo wchs | nc 127.0.0.1 $PORT`

   # Total number of watches established
   put_gauge 'local-watches-total' `echo $RAW_STAT | egrep -o 'Total watches:([0-9]+)' | awk -F: '{print $2}'`

   # Number of unique paths being watched
   put_gauge 'local-watches-unique-paths' `echo $RAW_STAT | egrep -o 'watching ([0-9]+) paths' | awk '{print $2}'`
}

# Loop through all of our stat collection functions and print them out on the $INTERVAL
while sleep "${INTERVAL}"; do
   get_srvr
   get_wchs
done