Calculate Aurora backup storage cost

calc_aurora_backup_storage_cost.sh

#!/bin/bash -eu

# Tokyo region
price=0.023
region='ap-northeast-1'

aws_accound_id=$(aws sts get-caller-identity --query 'Account' --output text)

echo "aws_accound_id,aurora_cluster,total_bk_storage,days,avg_bk_storage_per_month,avg_bk_storage_per_month_gb,cost_bk_storage"

aurora_clusters=$(aws cloudwatch list-metrics \
    --namespace AWS/RDS \
    --metric-name TotalBackupStorageBilled \
    --query 'Metrics[].Dimensions[0].Value' \
    --output text)

for aurora_cluster in ${aurora_clusters[@]}; do
    bk_storage_datapoints=$(aws cloudwatch get-metric-statistics \
        --namespace AWS/RDS \
        --metric-name TotalBackupStorageBilled \
        --dimensions Name=DBClusterIdentifier,Value=$aurora_cluster \
        --statistics Average \
        --start-time $(date --date "$(date +"%Y%m01")" "+%Y-%m-%dT%H:%M:%S") \
        --end-time $(date --date "$(date +"%Y%m01") 1 second ago + 1 month" "+%Y-%m-%dT%H:%M:%S") \
        --period 86400 \
        --query 'Datapoints[].Average' --output text)

    total_bk_storage=0
    days=0
    for bk_storage_datapoint in ${bk_storage_datapoints[@]}; do
        total_bk_storage=$(awk "BEGIN { print $total_bk_storage + $bk_storage_datapoint }")
        days=$((days + 1))
    done
    if [ $days -eq 0 ]; then
        continue
    fi

    # 当月分の平均バックアップストレージ量（Bytes）
    avg_bk_storage_per_month=$(awk "BEGIN { print $total_bk_storage / ($days * 24) }")  # 1day = 24hours

    # 当月分の平均バックアップストレージ量（GB）
    avg_bk_storage_per_month_gb=$(awk "BEGIN { print $avg_bk_storage_per_month / 1000 / 1000 / 1000 }")

    # バックアップストレージ料金
    cost_bk_storage=$(awk "BEGIN { print $avg_bk_storage_per_month_gb * $price }")

    echo "${aws_accound_id},${aurora_cluster},${total_bk_storage},${days},${avg_bk_storage_per_month},${avg_bk_storage_per_month_gb},${cost_bk_storage}"
done