Batch update ACL permissions on AWS.

aws_acl_updater.rb

# add AWS credentials to ENV variables or modify the script to pass in credentials
require 'thread'
require 'aws-sdk'

# settings
region   = 'my-region'
bucket   = 'my-bucket'
prefix   = 'my-prefix'
acl      = "private"
parallel = 25

# init
queue = Queue.new
consumers = []

print "-----> populating queue... "
total_items = 0
s3 = Aws::S3::Resource.new(region: region)
bucket = s3.bucket(bucket)
bucket.objects(prefix: prefix).each do |object|
  total_items += 1
  queue << object
end
puts "#{total_items} objects added."

puts "-----> starting #{parallel} consumer threads"
$total_updated = 0
parallel.times do |thread_i|
  consumers[thread_i] = Thread.new do
    while queue.length > 0
      $total_updated += 1
      object = queue.pop
      puts "[#{$total_updated}] #{object.key}"
      object.acl.put(acl: "private")
    end
  end.tap { |t| t.abort_on_exception = true }
end

consumers.each { |c| c.join }

puts "-----> done updating #{$total_updated}/#{total_items} objects."