class ActiveStorage::Service::MirrorService

Active Storage Mirror Service

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

Public Class Methods

new (primary:, mirrors:)

Source

# File lib/active_storage/service/mirror_service.rb, line 31
def initialize(primary:, mirrors:)
  @primary, @mirrors = primary, mirrors
  @executor = Concurrent::ThreadPoolExecutor.new(
    min_threads: 1,
    max_threads: mirrors.size,
    max_queue: 0,
    fallback_policy: :caller_runs,
    idle_time: 60
  )
end

Public Instance Methods

delete (key)

Source

# File lib/active_storage/service/mirror_service.rb, line 52
def delete(key)
  perform_across_services :delete, key
end

Delete the file at the key on all services.

delete_prefixed (prefix)

Source

# File lib/active_storage/service/mirror_service.rb, line 57
def delete_prefixed(prefix)
  perform_across_services :delete_prefixed, prefix
end

Delete files at keys starting with the prefix on all services.

mirror (key, checksum:)

Source

# File lib/active_storage/service/mirror_service.rb, line 66
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

Copy the file at the key from the primary service to each of the mirrors where it doesn’t already exist.

upload (key, io, checksum: nil, **options)

Source

# File lib/active_storage/service/mirror_service.rb, line 45
def upload(key, io, checksum: nil, **options)
  io.rewind
  primary.upload key, io, checksum: checksum, **options
  mirror_later key, checksum: checksum
end

Upload the io to the key specified to all services. The upload to the primary service is done synchronously whereas the upload to the mirrors is done asynchronously. If a checksum is provided, all services will ensure a match when the upload has completed or raise an ActiveStorage::IntegrityError.

Private Instance Methods

each_service (&block)

Source

# File lib/active_storage/service/mirror_service.rb, line 80
def each_service(&block)
  [ primary, *mirrors ].each(&block)
end

perform_across_services (method, *args)

Source

# File lib/active_storage/service/mirror_service.rb, line 84
def perform_across_services(method, *args)
  tasks = each_service.collect do |service|
    Concurrent::Promise.execute(executor: @executor) do
      service.public_send method, *args
    end
  end
  tasks.each(&:value!)
end