The best way to identify objects in bucket s3 that don't have cache-control defined

Hello Franck,

It seems like you want to identify all S3 objects that do not have the 'Cache-Control' metadata set. I don't think the AWS CLI provides a direct command to filter out such objects. But you can still accomplish it with a combination of commands.

Here's a basic example using AWS CLI and Bash to find S3 objects in a given bucket that do not have the 'Cache-Control' metadata set:

#!/bin/bash
bucket="your-bucket-name"  # replace with your bucket name
aws s3api list-objects --bucket $bucket | jq -r .Contents[].Key | while read key
do
    cache_control=$(aws s3api head-object --bucket $bucket --key "$key" | jq -r .Metadata.\"Cache-Control\")
    if [ "$cache_control" = "null" ]; then
        echo $key
    fi
done

In this script, we are:

1. Listing all objects in a bucket using aws s3api list-objects.
2. Iterating over each object key.
3. Using aws s3api head-object to get the metadata of each object.
4. Using jq to extract the 'Cache-Control' metadata.
5. Checking if 'Cache-Control' is 'null' (not set) and if so, printing out the object key.

This script will print out the keys of all objects that do not have 'Cache-Control' set.

Please note the following:

• You need to have the jq command-line JSON processor installed to run this script. If you don't have it, you can install it with sudo apt-get install jq on Ubuntu or brew install jq on macOS.
• If your bucket has a large number of objects, you should use the --page-size, --max-items, and --starting-token parameters with the list-objects command to retrieve the objects in smaller batches.
• You will be billed for the use of the s3api head-object API. Consider the cost if you have a large number of objects.
• If you have versioning enabled for your bucket, you should modify this script to handle object versions. The list-objects command does not return versions; you need to use the list-object-versions command instead.
• Replace "your-bucket-name" with the actual name of your S3 bucket.

Hope this helps!