capistrano-s3-arn.rb

#!/usr/bin/ruby

require 'aws-sdk'    # version 3

role_credentials = Aws::AssumeRoleCredentials.new(
    client: Aws::STS::Client.new(access_key_id:'',
                                 secret_access_key:''),
    role_arn: '',
    role_session_name: ''
)

s3 = Aws::S3::Resource.new(credentials: role_credentials, region: 'eu-central-1')
s3.buckets.limit(50).each do |b|
    puts "#{b.name}"
end

puts s3.bucket('oply.com-eu-central-1-819224168067').exists?