AWS Billing Bash script to consolidate costs

aws-billing.sh

#!/usr/bin/env /bin/bash

# Checks if element (first argument) is in array (second argument)
elementIn() {
    local e
    for e in "${@:2}"; do [[ "\"$e\"" == "$1" ]] && return 0; done
    return 1
}

# Id strings used to identify resources
PROJECT_STRING_IDS=(
"resource1"
"resource2"
"resource3"
)

# By default the scripts downloads the report from the previous month,
# but you can specify reports from other monts (Y-m format)
if [ -z "$1" ]; then
    if [[ "$OSTYPE" == "darwin"* ]]; then
        PERIOD=$(date -j -v -1m +%Y-%m)
    else
        PERIOD=$(date +%Y-%m -d 'last month')
    fi
else
    PERIOD=$1
fi

SRC_FILE=488669976369-aws-billing-detailed-line-items-with-resources-and-tags-$PERIOD.csv
SRC_PATH=s3://my-beloved-bucket
TMP_PATH=$(mktemp -d)
COST_FORMACION=0
COST_IMPACT=0
COST_OTHERS=0
LINE_COUNTER=1

# Download billing report automatically stored on S3 bucket
echo "Descargando reporte..."
aws s3 cp $SRC_PATH/$SRC_FILE.zip $TMP_PATH --only-show-errors

# Report is not available
if ! [ -f $TMP_PATH/$SRC_FILE.zip ]; then
    echo "El reporte no ha podido ser descargado."
    exit 1
fi

unzip -qq -o -d $TMP_PATH $TMP_PATH/$SRC_FILE

# Calculation (depressing performance, but whatever...)
echo "Calculando..."
while read line; do
    CLEAN_LINE=$(echo "$line" | awk -F'"' -v OFS='"' '{ for (i=2; i<=NF; i+=2) gsub(",", "", $i) } 1')

    IFS=',' read -ra sline <<< "$CLEAN_LINE"

    if [[ ${sline[9]} != "\"\"" ]]; then
        elementIn ${sline[19]} ${PROJECT_STRING_IDS[@]}

        if [[ $? -eq 0 ]]; then
            COST_FORMACION=$(perl -e "print $COST_FORMACION+${sline[18]}")
        else
            if [[ ${sline[19]} != "\"\"" ]]; then
                COST_IMPACT=$(perl -e "print $COST_IMPACT+${sline[18]}")
            else
                COST_OTHERS=$(perl -e "print $COST_OTHERS+${sline[18]}")
            fi
        fi

        # Debugging
        # echo "$LINE_COUNTER => $COST_FORMACION vs $COST_IMPACT"
        # LINE_COUNTER=$(($LINE_COUNTER + 1))
    fi
done < "$TMP_PATH/$SRC_FILE"

# Clean up
if [ -n "$TMP_PATH" ]; then
    rm -r $TMP_PATH
fi

echo "------------------------------------"
echo "Formacion... $COST_FORMACION"
echo "Impact...... $COST_IMPACT"
echo "Others...... $COST_OTHERS"
echo "------------------------------------"

# Just in case, we like to leave everything just as we found it
unset IFS