[deploy] Optimization:Store Podcast Ep Data in Redis, Rather than Sending as Sidekiq Argument (#10331)

app/services/podcasts/get_episode.rb

@@ -12,7 +12,9 @@ module Podcasts
       if episode
         try_update_media_url(episode: episode, item_data: item_data, force_update: force_update)
       else
-        PodcastEpisodes::CreateWorker.perform_async(podcast.id, item_data.to_h)
+        episode_cache_key = cache_key(item_data)
+        cache_episode_data(episode_cache_key, item_data)
+        PodcastEpisodes::CreateWorker.perform_async(podcast.id, episode_cache_key)
       end
     end
 
@@ -36,5 +38,13 @@ module Podcasts
     rescue ArgumentError, NoMethodError => e
       Rails.logger.error("not a valid date: #{e}")
     end
+
+    def cache_episode_data(episode_cache_key, item_data)
+      Rails.cache.write(episode_cache_key, item_data.to_h)
+    end
+
+    def cache_key(item_data)
+      Digest::SHA1.hexdigest(item_data.to_s)
+    end
   end
 end

app/workers/podcast_episodes/create_worker.rb

@@ -4,7 +4,10 @@ module PodcastEpisodes
 
     sidekiq_options queue: :high_priority
 
-    def perform(podcast_id, item)
+    def perform(podcast_id, episode_cache_key)
+      item = Rails.cache.read(episode_cache_key)
+      return unless item
+
       Podcasts::CreateEpisode.call(podcast_id, item.with_indifferent_access)
     end
   end

spec/services/podcasts/feed_spec.rb

@@ -96,7 +96,10 @@ RSpec.describe Podcasts::Feed, type: :service, vcr: vcr_option do
   end
 
   context "when creating" do
+    let(:cache_store) { ActiveSupport::Cache.lookup_store(:redis_cache_store) }
+
     before do
+      allow(Rails).to receive(:cache).and_return(cache_store)
       stub_request(:head, "https://traffic.libsyn.com/sedaily/AnalyseAsia.mp3").to_return(status: 200)
       stub_request(:head, "https://traffic.libsyn.com/sedaily/IFTTT.mp3").to_return(status: 200)
     end

spec/services/podcasts/get_episode_spec.rb

@@ -82,9 +82,10 @@ RSpec.describe Podcasts::GetEpisode, type: :service do
   end
 
   it "enqueues a worker to create an episode when it doesn't exist" do
+    cache_key = Digest::SHA1.hexdigest(item.to_s)
     allow(podcast).to receive(:existing_episode).and_return(nil)
 
-    sidekiq_assert_enqueued_with(job: PodcastEpisodes::CreateWorker, args: [podcast.id, item.to_h]) do
+    sidekiq_assert_enqueued_with(job: PodcastEpisodes::CreateWorker, args: [podcast.id, cache_key]) do
       described_class.new(podcast).call(item: item)
     end
   end

spec/workers/podcast_episodes/create_worker_spec.rb

@@ -1,30 +1,31 @@
 require "rails_helper"
 
 RSpec.describe PodcastEpisodes::CreateWorker, type: :worker do
-  include_examples "#enqueues_on_correct_queue", "high_priority", [123, {}]
+  include_examples "#enqueues_on_correct_queue", "high_priority", [123, "cache_key"]
 
   describe "#perform" do
     let(:worker) { subject }
 
     let(:podcast_id) { 781 }
-    let(:item) { { foo: "bar" } }
+    let(:cache_key) { "ep_cache_key" }
 
     before do
       allow(Podcasts::CreateEpisode).to receive(:call)
     end
 
     it "creates a podcast episode" do
-      worker.perform(podcast_id, item)
+      allow(Rails.cache).to receive(:read).and_return({})
+      worker.perform(podcast_id, cache_key)
 
-      expect(Podcasts::CreateEpisode).to have_received(:call).with(podcast_id, item).once
+      expect(Podcasts::CreateEpisode).to have_received(:call).with(podcast_id, {}).once
+      expect(Rails.cache).to have_received(:read).with(cache_key).once
     end
 
-    context "when item has string keys" do
-      it "creates a podcast episode regardless of whether item has string or symbol keys" do
-        worker.perform(podcast_id, item.stringify_keys)
+    it "does not create a podcast episode if item is not found" do
+      allow(Rails.cache).to receive(:read)
+      worker.perform(podcast_id, cache_key)
 
-        expect(Podcasts::CreateEpisode).to have_received(:call).with(podcast_id, item).once
-      end
+      expect(Podcasts::CreateEpisode).not_to have_received(:call)
     end
   end
 end