#!/usr/bin/env bash
#
# HOW TO:
# 
# 1. Create this script and place it in /bin/loadgen
# 2. Make script executable: chmod +x /bin/loadgen
# 3. Use wrk2 (# wrk2: https://github.com/giltene/wrk2) so we can define Rate -R, --rate:
#    Install wrk2: https://github.com/giltene/wrk2/wiki/Installing-wrk2-on-Linux
# 4. Install bc, the command-line calculator:
#    apt-get install bc
# 5. Make sure your date and timezone is configured, e.g. on ubuntu sudo dpkg-reconfigure tzdata
# Set cron job to run script EVERY 1 MINUTE
# * * * * * eval $(/bin/loadgen) >/dev/null 2>&1
#

# Set URL target and wrk2
TARGET=http://load.t3st.org/0kb.bin
# Absolute path to wrk2
WRK=/bin/wrk

# Set Rate per second in a array where index is the hour in 24hr Time
arr[0]=1000
arr[1]=800
arr[2]=600
arr[3]=600
arr[4]=800
arr[5]=1000
arr[6]=1500
arr[7]=2000
arr[8]=4000
arr[9]=6000
arr[10]=6500
arr[11]=7000
arr[12]=12000
arr[13]=18000
arr[14]=16000
arr[15]=14000
arr[16]=12000
arr[17]=13000
arr[18]=16500
arr[19]=18000
arr[20]=12000
arr[21]=6000
arr[22]=3000
arr[23]=2000

# Set the rate based on time (hr) of day
HR=$(date +"%-H") # (hyphen) do not pad the field i.e. 09 becomes 9
RATE=${arr[$HR]}
# Calculate a random variable rate within a percentage range                     
VAR_PERCENT=20                                                                   
VAR_DIFF=$(printf $(echo "scale=4; $VAR_PERCENT/100 * $RATE" | bc | cut -d . -f 1))
VAR_RATE_HIGH=$(echo "$RATE + $VAR_DIFF" | bc)
VAR_RATE_RANDOM=$[ ( $RANDOM % ( $[ $VAR_RATE_HIGH - $RATE ] + 1 ) ) + $RATE ]
#echo $VAR_DIFF
#echo $VAR_RATE_HIGH
#echo $VAR_RATE_RANDOM

# Horsepower
# Get Number of Cores on this machine
CORES=$(( $(lscpu | awk '/^Socket\(s\)/{ print $2 }') * $(lscpu | awk '/^Core\(s\) per socket/{ print $4 }') ))
# The -c option specifies the number of TCP connections to create. For our testing, we set this to a fixed amount e.g. 50 connections.
#CONNECTIONS=50
CONNECTIONS=$(($RATE / 4))

# The -d option specifies how long to generate traffic. We ran our tests for 61s each since we run a cron EVERY 1MIN
DURATION=61s

#
# Attack single target url
#
# Uncomment one out, HTTP or HTTPS
# HTTPS
# The client opens and closes a connection for each request (the -H option sets the Connection: close  HTTP header).
# HTTPS
# CMD="$WRK -t$CORES -c$CONNECTIONS -d$DURATION -R$RATE $TARGET -H 'Connection: close'" 
# HTTP
CMD="$WRK -t$CORES -c$CONNECTIONS -d$DURATION -R$VAR_RATE_RANDOM $TARGET"
echo $CMD

# vim: syntax=sh