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# frozen_string_literal: true
# The usage of the ReactiveCaching module is documented here:
# https://docs.gitlab.com/ee/development/utilities.html#reactivecaching
module ReactiveCaching
extend ActiveSupport::Concern
InvalidateReactiveCache = Class.new(StandardError)
ExceededReactiveCacheLimit = Class.new(StandardError)
included do
extend ActiveModel::Naming
class_attribute :reactive_cache_key
class_attribute :reactive_cache_lease_timeout
class_attribute :reactive_cache_refresh_interval
class_attribute :reactive_cache_lifetime
class_attribute :reactive_cache_hard_limit
class_attribute :reactive_cache_worker_finder
# defaults
self.reactive_cache_key = -> (record) { [model_name.singular, record.id] }
self.reactive_cache_lease_timeout = 2.minutes
self.reactive_cache_refresh_interval = 1.minute
self.reactive_cache_lifetime = 10.minutes
self.reactive_cache_hard_limit = 1.megabyte
self.reactive_cache_worker_finder = ->(id, *_args) do
find_by(primary_key => id)
end
def calculate_reactive_cache(*args)
raise NotImplementedError
end
def reactive_cache_updated(*args)
end
def with_reactive_cache(*args, &blk)
unless within_reactive_cache_lifetime?(*args)
refresh_reactive_cache!(*args)
return
end
keep_alive_reactive_cache!(*args)
begin
data = Rails.cache.read(full_reactive_cache_key(*args))
yield data unless data.nil?
rescue InvalidateReactiveCache
refresh_reactive_cache!(*args)
nil
end
end
# This method is used for debugging purposes and should not be used otherwise.
def without_reactive_cache(*args, &blk)
return with_reactive_cache(*args, &blk) unless Rails.env.development?
data = self.class.reactive_cache_worker_finder.call(id, *args).calculate_reactive_cache(*args)
yield data
end
def clear_reactive_cache!(*args)
Rails.cache.delete(full_reactive_cache_key(*args))
Rails.cache.delete(alive_reactive_cache_key(*args))
end
def exclusively_update_reactive_cache!(*args)
locking_reactive_cache(*args) do
key = full_reactive_cache_key(*args)
if within_reactive_cache_lifetime?(*args)
enqueuing_update(*args) do
new_value = calculate_reactive_cache(*args)
check_exceeded_reactive_cache_limit!(new_value)
old_value = Rails.cache.read(key)
Rails.cache.write(key, new_value)
reactive_cache_updated(*args) if new_value != old_value
end
else
Rails.cache.delete(key)
end
end
end
private
def refresh_reactive_cache!(*args)
clear_reactive_cache!(*args)
keep_alive_reactive_cache!(*args)
ReactiveCachingWorker.perform_async(self.class, id, *args)
end
def keep_alive_reactive_cache!(*args)
Rails.cache.write(alive_reactive_cache_key(*args), true, expires_in: self.class.reactive_cache_lifetime)
end
def full_reactive_cache_key(*qualifiers)
prefix = self.class.reactive_cache_key
prefix = prefix.call(self) if prefix.respond_to?(:call)
([prefix].flatten + qualifiers).join(':')
end
def alive_reactive_cache_key(*qualifiers)
full_reactive_cache_key(*(qualifiers + ['alive']))
end
def locking_reactive_cache(*args)
lease = Gitlab::ExclusiveLease.new(full_reactive_cache_key(*args), timeout: reactive_cache_lease_timeout)
uuid = lease.try_obtain
yield if uuid
ensure
Gitlab::ExclusiveLease.cancel(full_reactive_cache_key(*args), uuid)
end
def within_reactive_cache_lifetime?(*args)
Rails.cache.exist?(alive_reactive_cache_key(*args))
end
def enqueuing_update(*args)
yield
ReactiveCachingWorker.perform_in(self.class.reactive_cache_refresh_interval, self.class, id, *args)
end
def check_exceeded_reactive_cache_limit!(data)
return unless Feature.enabled?(:reactive_cache_limit)
data_deep_size = Gitlab::Utils::DeepSize.new(data, max_size: self.class.reactive_cache_hard_limit)
raise ExceededReactiveCacheLimit.new unless data_deep_size.valid?
end
end
end
|
