# frozen_string_literal: true
require "active_support/core_ext/module/delegation"
module ActiveStorage
# Wraps a set of mirror services and provides a single ActiveStorage::Service object that will all
# have the files uploaded to them. A +primary+ service is designated to answer calls to:
# * +download+
# * +exists?+
# * +url+
# * +url_for_direct_upload+
# * +headers_for_direct_upload+
class Service::MirrorService < Service
attr_reader :primary, :mirrors
delegate :download, :download_chunk, :exist?, :url,
:url_for_direct_upload, :headers_for_direct_upload, :path_for, to: :primary
# Stitch together from named services.
def self.build(primary:, mirrors:, configurator:, **options) #:nodoc:
new \
primary: configurator.build(primary),
mirrors: mirrors.collect { |name| configurator.build name }
end
def initialize(primary:, mirrors:)
@primary, @mirrors = primary, mirrors
end
# Upload the +io+ to the +key+ specified to all services. If a +checksum+ is provided, all services will
# ensure a match when the upload has completed or raise an ActiveStorage::IntegrityError.
def upload(key, io, checksum: nil, **options)
each_service.collect do |service|
io.rewind
service.upload key, io, checksum: checksum, **options
end
end
# Delete the file at the +key+ on all services.
def delete(key)
perform_across_services :delete, key
end
# Delete files at keys starting with the +prefix+ on all services.
def delete_prefixed(prefix)
perform_across_services :delete_prefixed, prefix
end
# Copy the file at the +key+ from the primary service to each of the mirrors where it doesn't already exist.
def mirror(key, checksum:)
instrument :mirror, key: key, checksum: checksum do
if (mirrors_in_need_of_mirroring = mirrors.select { |service| !service.exist?(key) }).any?
primary.open(key, checksum: checksum) do |io|
mirrors_in_need_of_mirroring.each do |service|
io.rewind
service.upload key, io, checksum: checksum
end
end
end
end
end
private
def each_service(&block)
[ primary, *mirrors ].each(&block)
end
def perform_across_services(method, *args)
# FIXME: Convert to be threaded
each_service.collect do |service|
service.public_send method, *args
end
end
end
end