Sorting S3 Buckets by Size

It can be fairly hard to rank your s3 buckets by size, especially with intelligent tiering on. Here is a concise script to find all bucket sizes in your account using cloudwatch metrics, that will output the top 10 in sorted order.

import boto3
import pandas as pd
from datetime import datetime, timedelta
import logging

# Configure logging
logging.basicConfig(format='%(asctime)s %(levelname)s: %(message)s', level=logging.INFO)

# Connect to CloudWatch
cloudwatch = boto3.client('cloudwatch')

# Connect to S3
s3 = boto3.resource('s3')

# Define a function to get the BucketSizeBytes metric data for a given bucket and storage type
def get_metric_data(bucket, storage_type):
    response = cloudwatch.get_metric_statistics(
            {'Name': 'BucketName', 'Value': bucket},
            {'Name': 'StorageType', 'Value': storage_type}
        StartTime=datetime.utcnow() - timedelta(days=3),
    datapoints = response['Datapoints']
    if datapoints:
        return max([datapoint['Maximum'] for datapoint in datapoints])
        return 0

# Log before pulling the list of bucket names"Getting list of bucket names...")

# Get all buckets in the account
buckets = [ for bucket in s3.buckets.all()]

# Prepare the MetricDataQueries for all the metrics
metric_data_queries = []
for bucket in buckets:"Working on bucket: {bucket}...")
    metric_data_queries.append(get_metric_data(bucket, 'StandardStorage'))
    metric_data_queries.append(get_metric_data(bucket, 'IntelligentTieringIAStorage'))
    metric_data_queries.append(get_metric_data(bucket, 'IntelligentTieringFAStorage'))
    metric_data_queries.append(get_metric_data(bucket, 'IntelligentTieringAIAStorage'))

# Parse the MetricData and sum up the bucket sizes
bucket_sizes = {}
for i in range(0, len(metric_data_queries), 4):
    bucket = buckets[i // 4]
    total_size = sum(metric_data_queries[i:i+4])
    bucket_sizes[bucket] = total_size

# Convert the results to a Pandas dataframe and display without truncation
df = pd.DataFrame.from_dict(bucket_sizes, orient='index', columns=['Size (Bytes)'])
df['Size (TBs)'] = df['Size (Bytes)'] / (1024 ** 4)
df = df[['Size (TBs)']].sort_values(by='Size (TBs)', ascending=False).head(10)
pd.set_option('display.max_rows', None)
pd.set_option('display.max_colwidth', None)
pd.set_option('display.width', None)
pd.set_option('display.float_format', '{:.2f}'.format)

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