Commit 02f17a09 authored by Rémy Coutable's avatar Rémy Coutable

Introduce a new CacheableAttributes concern

Signed-off-by: Rémy Coutable's avatarRémy Coutable <remy@rymai.me>
parent a2dbca4a
module CacheableAttributes
extend ActiveSupport::Concern
included do
after_commit { self.class.expire }
end
class_methods do
# Can be overriden
def current_without_cache
last
end
def cache_key
"#{name}:#{Gitlab::VERSION}:#{Gitlab.migrations_hash}:json".freeze
end
def defaults
{}
end
def build_from_defaults(attributes = {})
new(defaults.merge(attributes))
end
def cached
json_attributes = Rails.cache.read(cache_key)
return nil unless json_attributes.present?
build_from_defaults(JSON.parse(json_attributes))
end
def current
cached_record = cached
return cached_record if cached_record.present?
current_without_cache.tap { |current_record| current_record&.cache! }
rescue
# Fall back to an uncached value if there are any problems (e.g. Redis down)
current_without_cache
end
def expire
Rails.cache.delete(cache_key)
rescue
# Gracefully handle when Redis is not available. For example,
# omnibus may fail here during gitlab:assets:compile.
end
end
def cache!
Rails.cache.write(self.class.cache_key, attributes.to_json)
end
end
......@@ -9,6 +9,10 @@ module Gitlab
Settings
end
def self.migrations_hash
@_migrations_hash ||= Digest::MD5.hexdigest(ActiveRecord::Migrator.get_all_versions.to_s)
end
COM_URL = 'https://gitlab.com'.freeze
APP_DIRS_PATTERN = %r{^/?(app|config|ee|lib|spec|\(\w*\))}
SUBDOMAIN_REGEX = %r{\Ahttps://[a-z0-9]+\.gitlab\.com\z}
......
require 'spec_helper'
describe CacheableAttributes do
let(:minimal_test_class) do
Class.new do
include ActiveModel::Model
extend ActiveModel::Callbacks
define_model_callbacks :commit
include CacheableAttributes
def self.name
'TestClass'
end
def self.first
@_first ||= new('foo' => 'a')
end
def self.last
@_last ||= new('foo' => 'a', 'bar' => 'b')
end
attr_accessor :attributes
def initialize(attrs = {})
@attributes = attrs
end
end
end
shared_context 'with defaults' do
before do
minimal_test_class.define_singleton_method(:defaults) do
{ foo: 'a', bar: 'b', baz: 'c' }
end
end
end
describe '.current_without_cache' do
it 'defaults to last' do
expect(minimal_test_class.current_without_cache).to eq(minimal_test_class.last)
end
it 'can be overriden' do
minimal_test_class.define_singleton_method(:current_without_cache) do
first
end
expect(minimal_test_class.current_without_cache).to eq(minimal_test_class.first)
end
end
describe '.cache_key' do
it 'excludes cache attributes' do
expect(minimal_test_class.cache_key).to eq("TestClass:#{Gitlab::VERSION}:#{Gitlab.migrations_hash}:json")
end
end
describe '.defaults' do
it 'defaults to {}' do
expect(minimal_test_class.defaults).to eq({})
end
context 'with defaults defined' do
include_context 'with defaults'
it 'can be overriden' do
expect(minimal_test_class.defaults).to eq({ foo: 'a', bar: 'b', baz: 'c' })
end
end
end
describe '.build_from_defaults' do
include_context 'with defaults'
context 'without any attributes given' do
it 'intializes a new object with the defaults' do
expect(minimal_test_class.build_from_defaults).not_to be_persisted
end
end
context 'without attributes given' do
it 'intializes a new object with the given attributes merged into the defaults' do
expect(minimal_test_class.build_from_defaults(foo: 'd').attributes[:foo]).to eq('d')
end
end
end
describe '.current', :use_clean_rails_memory_store_caching do
context 'redis unavailable' do
it 'returns an uncached record' do
allow(minimal_test_class).to receive(:last).and_return(:last)
expect(Rails.cache).to receive(:read).and_raise(Redis::BaseError)
expect(minimal_test_class.current).to eq(:last)
end
end
context 'when a record is not yet present' do
it 'does not cache nil object' do
# when missing settings a nil object is returned, but not cached
allow(minimal_test_class).to receive(:last).twice.and_return(nil)
expect(minimal_test_class.current).to be_nil
expect(Rails.cache.exist?(minimal_test_class.cache_key)).to be(false)
end
it 'cache non-nil object' do
# when the settings are set the method returns a valid object
allow(minimal_test_class).to receive(:last).and_call_original
expect(minimal_test_class.current).to eq(minimal_test_class.last)
expect(Rails.cache.exist?(minimal_test_class.cache_key)).to be(true)
# subsequent calls retrieve the record from the cache
last_record = minimal_test_class.last
expect(minimal_test_class).not_to receive(:last)
expect(minimal_test_class.current.attributes).to eq(last_record.attributes)
end
end
end
describe '.cached', :use_clean_rails_memory_store_caching do
context 'when cache is cold' do
it 'returns nil' do
expect(minimal_test_class.cached).to be_nil
end
end
context 'when cached settings do not include the latest defaults' do
before do
Rails.cache.write(minimal_test_class.cache_key, { bar: 'b', baz: 'c' }.to_json)
minimal_test_class.define_singleton_method(:defaults) do
{ foo: 'a', bar: 'b', baz: 'c' }
end
end
it 'includes attributes from defaults' do
expect(minimal_test_class.cached.attributes[:foo]).to eq(minimal_test_class.defaults[:foo])
end
end
end
describe '#cache!', :use_clean_rails_memory_store_caching do
let(:appearance_record) { create(:appearance) }
it 'caches the attributes' do
appearance_record.cache!
expect(Rails.cache.read(Appearance.cache_key)).to eq(appearance_record.attributes.to_json)
end
end
end
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