#!/bin/sh

# Freenet monitor script.  Requires printf(1), nc(1) (netcat) and bc(1).
# [cc] Counter-copyright 2003 Greg Wooledge.  This program is in the public
# domain.  It may be used, distributed and/or modified without restrictions.

# This program is provided "as is" without waranty of any kind, either
# expressed or implied, including, but not limited to, the implied waranties of
# merchantability and fitness for a particular purpose.  The entire risk as
# to the quality and performance of the program is with you.  Should the
# program prove defective, you assume the cost of all necessary servicing,
# repair or correction.

# You may be able to find older and/or newer versions of this program at
# http://wooledge.org/~greg/fmonitor/ .  Then again, you may not.

# Basic algorithm: we check the Local mean traffic (queries per hour)
# via the web interface (default port 8888) every 60 seconds.  We keep
# a running average of the last three values, to avoid weirdness from any
# sudden spikes.
#
# Using the running average values, we keep track of the peak traffic
# that the node has seen.  If the running average for the node falls below
# epslion percent of the peak, we do something.

# Configuration variables:

NODEHOST=127.0.0.1
NODEPORT=8888
LOADURL=/servlet/nodeinfo/networking/loadstats
GREPSTRING='Local mean traffic'
# The exact format of the line is somewhat hard-coded in the script below.
# So it's not *completely* configurable using only these variables.

SLEEPTIME=60
EPSILON=0.05
ACTION='echo Peak $peak last2 $last2 last1 $last1 now $now |
    mailx -s "Your node needs you" greg; exit 0'


# Internal variables:

peak=0
last2=0
last1=0
now=0

# Main loop:

while :; do
    last2=$last1
    last1=$now
    now=`printf "GET $LOADURL HTTP/1.0\n\n" | nc $NODEHOST $NODEPORT |
        grep "$GREPSTRING" | sed -e 's#^.*: ##' -e 's#</li>$##'`
    average=`printf "scale=2\n ($last2 + $last1 + $now) / 3\n" | bc`
    printf "%s  %.2f\t%.2f\t%.2f\t%.2f\n" \
        `date +%H:%M` $last2 $last1 $now $average

    # bc returns 1 if the expression is true.  We can't do floats in /bin/sh.
    if [ `echo $average \> $peak | bc` = 1 ]; then
        peak=$average
	echo "** New peak $peak"
    elif [ `echo $average \< \($peak \* $EPSILON\) | bc` = 1 ]; then
	echo "** Load $average less than $EPSILON of peak $peak"
        eval $ACTION
    fi
    sleep $SLEEPTIME
done