get last 1 month's size of the s3 bucket

cloudwatch_get_s3_bucket_size.py

def get_bucket_size_from_cloudwatch(bucket_name, region_name):
    cloudwatch = boto3.client('cloudwatch', region_name=region_name)
    response = cloudwatch.get_metric_statistics(
        Namespace='AWS/S3',
        MetricName='BucketSizeBytes',
        Dimensions=[{'Name': 'BucketName', 'Value': bucket_name}, {'Name': 'StorageType', 'Value': 'StandardStorage'}],
        StartTime=datetime.utcnow() - timedelta(days=30),
        EndTime=datetime.utcnow(),
        Period=86400,
        Statistics=['Average']
    )
    if datapoints := response.get('Datapoints', []):
        return datapoints[-1]['Average']
    else:
        return 0
# %%
bucket_name = '316381694901-propellor'
region_name = 'ap-south-1'
bucket_size = get_bucket_size_from_cloudwatch(bucket_name, region_name)
# %%
bucket_in_GB = round(bucket_size/1000000000,2)