little website latency test script

plot_latency.sh

#!/bin/bash

function join_by { local d=$1; shift; echo -n "$1"; shift; printf "%s" "${@/#/$d}"; }

export LC_ALL=C

urls=("$@")
data="$(mktemp)"

exec 5> >(gnuplot)

cat >&5 << EOF
set terminal x11
set grid y
set xlabel 'request'
set ylabel 'response'
EOF

echo "time" > "${data}"
plotline=()
for i in "${!urls[@]}"; do 
  echo -ne "\"${urls[$i]}\"\t" >> "${data}"
  idx=$(( $i + 2 ))
  plotline[$i]="\"${data}\" using $idx:xticlabels(1) smooth sbezier with lines title \"${urls[$i]}\""
done
echo '' >> "${data}"

plotline="plot $(join_by ', ' "${plotline[@]}")"

while true
do
  now="$(date +%X)"
  echo -n "\"$now\"" >> "${data}"
  for url in "${urls[@]}"
  do
    t=$(curl -o /dev/null -s -w %{time_total} $url)
    t=$( echo "$t * 1000 " | bc)
    echo -ne "\t$t" >> "${data}"
  done
  echo "" >> "${data}"
  echo $plotline >&5
  sleep .5
done