Simple, concurrent HTTP load test in bash

load-test.sh

#!/bin/bash

# Config
concurrency=20
lag=0.05
precision=3
curl_format="%{time_total}"

# Runtime
pids=()
batch=0
tmp="$(mktemp -d "/tmp/$(basename "$0").XXXXXX")" || {
	echo "Error creating temporary directory" >&2
	exit 1
}

function parse_args(){
	local args=""
	for a in "${@}"; do
		if [[ $a != \-* ]]; then
			a="'$a'"
		fi
		args="$args $a"
	done
	echo "$args"
}

function get_command(){
	echo "curl -s --insecure -w '$curl_format' -o /dev/null -m 1 ${@}"
}

function analyze(){
	read -ra result_files <<< $(ls $tmp/r.$batch.*)
	read -ra result_times <<< $(
		for f in ${result_files[@]}; do
			cat $f
		done
	)
	average=$({
		total=0
		for t in ${result_times[@]}; do
			total=$(bc <<< "$total+$t")
		done
		printf "%.3f" $(bc <<< "scale=$precision;$total/${#result_times[@]}")
	})
	echo "average=${average}s"
}

if [ $# -eq 0 ]; then
	echo -e "\nusage: ./load-test.sh <args>\n"
	echo -e "\t=> $(get_command "<args>")\n"
	exit 1;
fi

trap "{ xargs kill -9 <<< \$(printf \"%s\n\" \"\${pids[@]}\"); rm -R $tmp; } &> /dev/null; exit" SIGINT SIGTERM

args=$(parse_args "${@}")

while [[ true ]]; do
	pids=()
	printf "Batch #$batch "
	for i in $(seq 1 $concurrency); do
		{
			metrics=$(eval $(get_command $args))
			echo "$metrics" > "$tmp/r.$batch.$i"
			printf "."
		} &
		pids+=($!)
		sleep $lag
	done
	wait

	echo " $(analyze)"
	((batch++))
done