Compare AWS ELB response times

elb_compare.sh

#!/bin/bash

# compare AWS ELB: CLB (classic) and ALB (application) response times
# all output times are in seconds

CLB_URL="https://clb.example.com"
ALB_URL="https://alb.example.com"

clb_wins=0
alb_wins=0

echo -e "CLB Time\tALB Time\tDifference\tWinner\tCLB Wins\tALB Wins"
while true; do

	start=`date +%s.%N`
	curl $ALB_URL &> /dev/null
	end=`date +%s.%N`

	alb_walltime=$(echo "$end-$start" | bc)

	start=`date +%s.%N`
	curl $CLB_URL &> /dev/null
	end=`date +%s.%N`

	clb_walltime=$(echo "$end-$start" | bc)

	if [ $(echo "define abs(x) {if (x<0) {return -x}; return x;}; abs($clb_walltime-$alb_walltime) < 0.001" | bc) -eq 1 ]; then
		winner="tie"
	else
		if [ $(echo "$clb_walltime>$alb_walltime" | bc) -eq 1 ] ; then
			winner="alb"
			alb_wins=$((alb_wins + 1))
		else
			winner="clb"
			clb_wins=$((clb_wins + 1))
		fi
	fi
	echo -e "$clb_walltime\t$alb_walltime\t"$(echo "$clb_walltime-$alb_walltime" | bc)"\t$winner\t$clb_wins\t$alb_wins"

	sleep 0.1
done