I have a bucket with 10^6 keys in it. I want to make all objects in it private.

I tried s3cmd which fails after sometime. I tried it with boto3, but it is painfully slow.

import boto3

boto3.setup_default_session(aws_access_key_id=access_key_id, aws_secret_access_key=secret_access_key)
s3_client = boto3.client('s3')
s3_resource = boto3.resource('s3')

bucket = s3_resource.Bucket(bucket_name)
bucket_acl = bucket.Acl()

i = 0

for object_summary in bucket.objects.all():
    i += 1
    object_acl = object_summary.Acl()
    if i % 100 == 1:
        print('{} {}'.format(i, object_summary.key))

    object_acl.put(ACL='private')

Is there any way to do batch operation or do everything private by setting some bucket policy.

Any other suggestion is also welcome.