A script to completely empty a versioned S3 bucket, in preparation for deletion. Run with `--help` to see the help information. Core details from this excellent StackOverflow advice: https://stackoverflow.com/a/61123579

empty-bucket.sh

#!/bin/bash

set -e
set -o pipefail

usage() {
  cat << EOF
Dangerous script. This script will empty a specified bucket.

Options:
    -b <bucket>             --bucket <bucket>             Sets the bucket to empty
    -r <region>             --region <region>             Sets the region (default: eu-west-2)
    -y                      --yes                         Confirm that you really wish to do this
    -h                      --help                        Prints this help message and exits
EOF
}

# prevent paging
export AWS_PAGER=""

# defaults
REGION=eu-west-2

while [ -n "$1" ]; do
  case $1 in
    -y | --yes)
        CONFIRMATION=yes
        ;;
    -r | --region)
        shift
        REGION=$1
        ;;
    -b | --bucket)
        shift
        BUCKET=$1
        ;;
    -h | --help)
        usage
        exit 0
        ;;
    *)
        echo -e "Unknown option $1...\n" >&2
        usage
        exit 1
        ;;
    esac
    shift
done

if [ -z "$BUCKET" ]; then
    echo "Please provide the bucket name."
    echo
    usage
    exit 1
fi

if [ -z "$CONFIRMATION" ]; then
    echo "This will delete everything in bucket: $BUCKET"
    read -p "Are you sure? " -n 1 -r
    echo
    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
        exit 1
    fi
fi

# check if the bucket exists
S3LS=$(aws s3 ls --region $REGION | grep "$BUCKET" || true)
if [ -z "${S3LS}" ]; then
    echo "Bucket $BUCKET does not exist."
    exit 0
fi

# delete everything in the bucket (unversioned, optimistic)
echo "Naive deletion of all objects in bucket $BUCKET..."
aws s3 rm s3://$BUCKET --region $REGION --recursive
echo

# versioned buckets also need you to delete all object versions and deletion markers
echo "Deleting all object versions and deletion markers in bucket $BUCKET..."
echo

# delete all object versions
NB_OBJECTS=$(aws s3api list-object-versions --bucket ${BUCKET} --query='length(Versions[*] || `[]` )' | awk '{ print $1 }')
echo "Found: ${NB_OBJECTS} object Versions to remove..."
if [[ "$NB_OBJECTS" != "0" ]]; then
  start=$SECONDS
  while [[ $NB_OBJECTS -gt 0 ]]
  do
    aws s3api delete-objects --bucket ${BUCKET} --delete "$(aws s3api list-object-versions --bucket ${BUCKET} --max-items 500 --query='{Objects: Versions[0:500].{Key:Key,VersionId:VersionId}}')" --query 'length(Deleted[*] || `[]` )' > /dev/null
    NB_OBJECTS=$((NB_OBJECTS  > 500 ? NB_OBJECTS - 500 : 0))
    echo " - Remaining: $NB_OBJECTS ($(( SECONDS - start ))s)"
  done
fi
echo

# delete all deletion markers
NB_OBJECTS=$(aws s3api list-object-versions --bucket ${BUCKET} --query='length(DeleteMarkers[*] || `[]` )' | awk '{ print $1 }')
echo "Found: ${NB_OBJECTS} DeleteMarkers to remove..."
if [[ "$NB_OBJECTS" != "0" ]]; then
  start=$SECONDS
  while [[ $NB_OBJECTS -gt 0 ]]
  do
    aws s3api delete-objects --bucket ${BUCKET} --delete "$(aws s3api list-object-versions --bucket ${BUCKET} --max-items 500 --query='{Objects: DeleteMarkers[0:500].{Key:Key,VersionId:VersionId}}')" --query 'length(Deleted[*] || `[]` )' > /dev/null
    NB_OBJECTS=$((NB_OBJECTS  > 500 ? NB_OBJECTS - 500 : 0))
    echo " - Remaining: $NB_OBJECTS ($(( SECONDS - start ))s)"
  done
fi
echo

# fin
echo "Bucket $BUCKET has been emptied."
echo