5caced3650
Add support for defining a reactive_cache_worker_finder function that will be used by the reactive_caching_worker to generate/initialize the calling object. This allows reactive caching to work with Services where the object cannot be obtained from DB but a new object can be initialized.
235 lines
5.9 KiB
Ruby
235 lines
5.9 KiB
Ruby
# frozen_string_literal: true
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require 'spec_helper'
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describe ReactiveCaching, :use_clean_rails_memory_store_caching do
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include ExclusiveLeaseHelpers
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include ReactiveCachingHelpers
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class CacheTest
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include ReactiveCaching
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self.reactive_cache_key = ->(thing) { ["foo", thing.id] }
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self.reactive_cache_lifetime = 5.minutes
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self.reactive_cache_refresh_interval = 15.seconds
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attr_reader :id
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def self.primary_key
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:id
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end
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def initialize(id, &blk)
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@id = id
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@calculator = blk
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end
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def calculate_reactive_cache
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@calculator.call
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end
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def result
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with_reactive_cache do |data|
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data
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end
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end
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end
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let(:calculation) { -> { 2 + 2 } }
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let(:cache_key) { "foo:666" }
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let(:instance) { CacheTest.new(666, &calculation) }
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describe '#with_reactive_cache' do
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before do
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stub_reactive_cache
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end
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subject(:go!) { instance.result }
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context 'when cache is empty' do
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it { is_expected.to be_nil }
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it 'enqueues a background worker to bootstrap the cache' do
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expect(ReactiveCachingWorker).to receive(:perform_async).with(CacheTest, 666)
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go!
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end
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it 'updates the cache lifespan' do
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expect(reactive_cache_alive?(instance)).to be_falsy
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go!
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expect(reactive_cache_alive?(instance)).to be_truthy
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end
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end
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context 'when the cache is full' do
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before do
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stub_reactive_cache(instance, 4)
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end
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it { is_expected.to eq(4) }
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it 'does not enqueue a background worker' do
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expect(ReactiveCachingWorker).not_to receive(:perform_async)
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go!
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end
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it 'updates the cache lifespan' do
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expect(Rails.cache).to receive(:write).with(alive_reactive_cache_key(instance), true, expires_in: anything)
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go!
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end
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context 'and expired' do
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before do
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invalidate_reactive_cache(instance)
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end
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it { is_expected.to be_nil }
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end
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context 'when cache was invalidated' do
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it 'refreshes cache' do
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expect(ReactiveCachingWorker).to receive(:perform_async).with(CacheTest, 666)
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instance.with_reactive_cache { raise described_class::InvalidateReactiveCache }
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end
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end
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end
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context 'when cache contains non-nil but blank value' do
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before do
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stub_reactive_cache(instance, false)
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end
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it { is_expected.to eq(false) }
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end
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end
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describe '.reactive_cache_worker_finder' do
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context 'with default reactive_cache_worker_finder' do
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let(:args) { %w(other args) }
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before do
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allow(instance.class).to receive(:find_by).with(id: instance.id)
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.and_return(instance)
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end
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it 'calls the activerecord find_by method' do
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result = instance.class.reactive_cache_worker_finder.call(instance.id, *args)
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expect(result).to eq(instance)
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expect(instance.class).to have_received(:find_by).with(id: instance.id)
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end
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end
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context 'with custom reactive_cache_worker_finder' do
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let(:args) { %w(arg1 arg2) }
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let(:instance) { CustomFinderCacheTest.new(666, &calculation) }
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class CustomFinderCacheTest < CacheTest
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self.reactive_cache_worker_finder = ->(_id, *args) { from_cache(*args) }
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def self.from_cache(*args); end
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end
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before do
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allow(instance.class).to receive(:from_cache).with(*args).and_return(instance)
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end
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it 'overrides the default reactive_cache_worker_finder' do
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result = instance.class.reactive_cache_worker_finder.call(instance.id, *args)
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expect(result).to eq(instance)
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expect(instance.class).to have_received(:from_cache).with(*args)
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end
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end
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end
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describe '#clear_reactive_cache!' do
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before do
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stub_reactive_cache(instance, 4)
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instance.clear_reactive_cache!
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end
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it { expect(instance.result).to be_nil }
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it { expect(reactive_cache_alive?(instance)).to be_falsy }
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end
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describe '#exclusively_update_reactive_cache!' do
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subject(:go!) { instance.exclusively_update_reactive_cache! }
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context 'when the lease is free and lifetime is not exceeded' do
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before do
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stub_reactive_cache(instance, "preexisting")
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end
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it 'takes and releases the lease' do
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expect_to_obtain_exclusive_lease(cache_key, 'uuid')
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expect_to_cancel_exclusive_lease(cache_key, 'uuid')
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go!
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end
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it 'caches the result of #calculate_reactive_cache' do
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go!
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expect(read_reactive_cache(instance)).to eq(calculation.call)
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end
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it "enqueues a repeat worker" do
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expect_reactive_cache_update_queued(instance)
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go!
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end
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it "calls a reactive_cache_updated only once if content did not change on subsequent update" do
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expect(instance).to receive(:calculate_reactive_cache).twice
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expect(instance).to receive(:reactive_cache_updated).once
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2.times { instance.exclusively_update_reactive_cache! }
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end
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context 'and #calculate_reactive_cache raises an exception' do
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before do
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stub_reactive_cache(instance, "preexisting")
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end
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let(:calculation) { -> { raise "foo"} }
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it 'leaves the cache untouched' do
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expect { go! }.to raise_error("foo")
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expect(read_reactive_cache(instance)).to eq("preexisting")
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end
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it 'enqueues a repeat worker' do
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expect_reactive_cache_update_queued(instance)
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expect { go! }.to raise_error("foo")
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end
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end
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end
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context 'when lifetime is exceeded' do
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it 'skips the calculation' do
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expect(instance).to receive(:calculate_reactive_cache).never
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go!
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end
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end
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context 'when the lease is already taken' do
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it 'skips the calculation' do
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stub_exclusive_lease_taken(cache_key)
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expect(instance).to receive(:calculate_reactive_cache).never
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go!
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end
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end
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end
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end
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