costcalculator

#!/bin/bash
#syntax: costcalculator <CONTAINER> <NREQUESTS> <DURATION> <MEMORY> [FREE] [MEMORYTIER]
# CONTAINER is the name of the container
# NREQUESTS is the number of requests to calculate the cost on
# DURATION is the duration of the function (in ms)
# MEMORY is the total memory in bytes allocated to the function. 
# FREE is a boolean indicating whether to consider the free tier requests and computation time or not. By default is false
# MEMORYTIER is the provider's memory tier used by the function.
## If not set, it will be rounded up to the nearest value available from MEMORY.
## If set but tier is non existent, it will be rounded up to the nearest value available from the set value.

if [ $# -lt 4 ]
then
	echo "Insufficient arguments. Check source for invocation help." >&2
	exit 1
fi

# Ceiling division function
ceildiv() {
    echo $((($1+$2-1)/$2));
}

#Set container arguments
NREQUESTS=$2
DURATION=$3
MEMORY="$(ceildiv $4 1048576)"

if [ -z $5 ]
then
    FREE=false
else
    FREE=$5
fi

#Set provider values
#PROV_REQUESTS="$(ceildiv $NREQUESTS 1000000)" Counts only per million of requests
PROV_REQUESTS=$(bc <<< $NREQUESTS/1000000)
PROV_DURATION="$(ceildiv $DURATION 100)"

if [ -z $6 ]
then
    aux_mem=$(($MEMORY-128)) 
else
    aux_mem="$(ceildiv $6 1048576)"
    aux_mem=$(($aux_mem-128))
fi

if [ "$aux_mem" -gt "0" ]
then
    prov_mult="$(ceildiv $aux_mem 64)"
else
    prov_mult=0
fi

PROV_MEMORY=$((128+$prov_mult*64))

while read mem freeseconds compute freerequests invocation
do
    if [ "$mem" = "$PROV_MEMORY" ]
    then
        FREE_TIER_SECONDS=$freeseconds
        COSTCOMPUTE=$compute
        NET_COSTCOMPUTE=$(bc -l <<< "$compute*$MEMORY/$PROV_MEMORY")
        FREE_REQUESTS=$freerequests
        COSTINVOCATION=$invocation
        break
    fi
done < calculator/costs_aws.dat

#Calculate cost
if [ "$FREE" = true ]
then
    # Calculate the cost with free requests and computation time
    aux_duration=$(bc <<< $PROV_DURATION*$PROV_REQUESTS*1000000-$FREE_TIER_SECONDS*10)
    aux_requests=$(($PROV_REQUESTS-$FREE_REQUESTS))
    aux_net_duration=$(bc <<< $DURATION*$PROV_REQUESTS*10000-$FREE_TIER_SECONDS*10)
    
    PROV_COST=$(bc <<< $aux_duration*$COSTCOMPUTE+$aux_requests*$COSTINVOCATION)
    PROV_NETCOST=$(bc <<< $aux_net_duration*$NET_COSTCOMPUTE+$aux_requests*$COSTINVOCATION)
    PERC_WASTEDMEMORY=$(bc -l <<< "(($aux_net_duration*$COSTCOMPUTE+$aux_requests*$COSTINVOCATION)/$PROV_COST)*100-100")
    PERC_WASTEDTIME=$(bc -l <<< "(($aux_duration*$NET_COSTCOMPUTE+$aux_requests*$COSTINVOCATION)/$PROV_COST)*100-100")
else
    # Calculate the cost without free requests and computation time
    PROV_COST=$(bc <<< $PROV_DURATION*$PROV_REQUESTS*1000000*$COSTCOMPUTE+$PROV_REQUESTS*$COSTINVOCATION)
    PROV_NETCOST=$(bc <<< $DURATION*$PROV_REQUESTS*10000*$NET_COSTCOMPUTE+$PROV_REQUESTS*$COSTINVOCATION)
    PERC_WASTEDMEMORY=$(bc -l <<< "(($DURATION*$PROV_REQUESTS*10000*$COSTCOMPUTE+$PROV_REQUESTS*$COSTINVOCATION)/$PROV_NETCOST)*100-100")
    PERC_WASTEDTIME=$(bc -l <<< "(($PROV_DURATION*$PROV_REQUESTS*1000000*$NET_COSTCOMPUTE+$PROV_REQUESTS*$COSTINVOCATION)/$PROV_NETCOST)*100-100")
fi

OVERHEAD_COST=$(bc <<< $PROV_COST-$PROV_NETCOST)

#Print results
echo "=== AWS ==="
echo "The function used $MEMORY MB of memory and was allocated $PROV_MEMORY MB by the cloud provider."
echo "The total cost for FaaS (AWS Lambda) for $PROV_REQUESTS million requests per month would be $`printf "%.2f" $PROV_COST`"
echo "The net cost would be $`printf "%.2f" $PROV_NETCOST`, and the overhead cost $`printf "%.2f" $OVERHEAD_COST`"

echo "The price increases `printf "%.2f" $PERC_WASTEDMEMORY`% due to wasted memory, and `printf "%.2f" $PERC_WASTEDTIME`% due to wasted computation time"

#Calculate waste
DURATION_WASTE=$(($PROV_DURATION*100-$DURATION))
MEMORY_WASTE="$(($PROV_MEMORY-$MEMORY))"

echo "$DURATION_WASTE milliseconds of computation time are being wasted."
echo "$MEMORY_WASTE MB of memory are being wasted"

#Write results into a file
FILE="$1-results".dat
if test -f "$FILE"; then
    #Time(ms)    Memory(MB)    Prov Time(ms)    Prov Memory(ms)    Prov Cost($)    Net cost($)    Overhead cost($)
    echo "$DURATION $MEMORY $PROV_DURATION   $PROV_MEMORY $PROV_COST    $PROV_NETCOST    $OVERHEAD_COST" >> $FILE
fi