AWS の S3 のファイルを別の bucket にコピーする方法 ref: http://qiita.com/mat_aki/items/90205144c3f93758e357

file0.rb

require 'right_aws'

aws_access_key_id, aws_secret_access_key = "key_id", "access_key"
old_bucket_name = 'from-bucket'
new_bucket_name = "to-bucket"

s3 = RightAws::S3.new(aws_access_key_id, aws_secret_access_key)
bucket = s3.bucket(old_bucket_name)

puts "Copy S3 files from '#{old_bucket_name}' to '#{new_bucket_name}'"

total_count = bucket.keys.count
puts "total_count: #{total_count}"

print "Are you sure? (y/N) > "
if gets.strip == 'y'
  puts "Start to copy at #{Time.now}"
  bucket.keys.each_with_index do |key, i|
    print "\r#{i}"
    s3.interface.copy(old_bucket_name, key.name, new_bucket_name, key.name)
  end
end

file1.rb

require "rubygems"
require 'right_aws'
require "parallel"

aws_access_key_id, aws_secret_access_key = "xxx", "xxx"
new_bucket_email_address = "[email protected]"

old_bucket_name = 'old'
new_bucket_name = "new"

s3 = RightAws::S3.new(aws_access_key_id, aws_secret_access_key)
bucket = RightAws::S3::Bucket.new(s3, old_bucket_name)

puts "Copy S3 files from '#{old_bucket_name}' to '#{new_bucket_name}'"

total_count = bucket.keys.count
puts "total_count: #{total_count}"

print "Are you sure? (y/N) > "
if gets.strip == 'y'
  Parallel.each_with_index(bucket.keys, in_processes: 10) do |key, i|
    print "\r#{i}: #{key}"
    s3.interface.copy(old_bucket_name, key.name, new_bucket_name, key.name, :replace, {'x-amz-grant-full-control' => %!emailAddress="#{new_bucket_email_address}"!, 'x-amz-grant-read' => 'uri=http://acs.amazonaws.com/groups/global/AllUsers'})
  end
end

アカウントを跨いでコピーする場合は、old_bucketのbucket policyに以下を追加する必要があるよん！

{
"Version": "2008-10-17",
"Id": "Policy1345626759739",
"Statement": [
{
"Sid": "Stmt1345626754496",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::＜new_bucketのオーナーID12桁＞:root"
},
"Action": "s3:",
"Resource": "arn:aws:s3:::＜old_bucket_name＞/"
}
]
}