How to check when is the last time S3 bucket has been updated?

Question

Does S3 bucket has information in regard to when is the last time it has been updated? How can I find the last time any of the objects in the bucket were updated?

Answer 1

As others have commented, there's no magic bit of metadata that stores this information. You just have to loop over the objects.

Code to do that with boto3:

import boto3
from datetime import datetime

def bucket_last_modified(bucket_name: str) -> datetime:
    """
    Given an S3 bucket, returns the last time that any of its objects was
    modified, as a timezone-aware datetime.
    """
    s3 = boto3.resource('s3')
    bucket = s3.Bucket(bucket_name)
    objects = list(bucket.objects.all())
    return max(obj.last_modified for obj in objects)

Answer 2

There is no native support for bucket last modified time. The way I do it is to use aws cli , sort the output, take the bottom line and print the first 2 fields.

$ aws s3 ls mybucket --recursive | sort | tail -n 1 | cut -d ' ' -f1,2
2016-03-18 22:46:48