Create rake Task to Destroy Old Notifications (#5180) [deploy]

app/models/notification.rb

@@ -136,6 +136,10 @@ class Notification < ApplicationRecord
       Notifications::UpdateJob.perform_later(notifiable.id, notifiable.class.name, action)
     end
 
+    def fast_destroy_old_notifications(destroy_before_timestamp = 4.months.ago)
+      Notification.where("created_at < ?", destroy_before_timestamp).in_batches(of: 10_000).delete_all
+    end
+
     private
 
     def user_data(user)

lib/tasks/fetch.rake

@@ -37,8 +37,8 @@ task expire_old_listings: :environment do
   end
 end
 
-task clear_memory_if_too_high: :environment do
-  Rails.cache.clear if Rails.cache.stats.flatten[1]["bytes"].to_i > 9_650_000_000
+task remove_old_notifications: :environment do
+  Notification.fast_destroy_old_notifications
 end
 
 task save_nil_hotness_scores: :environment do

spec/factories/notifications.rb

@@ -1,4 +1,7 @@
 FactoryBot.define do
   factory :notification do
+    association :user, factory: :user, strategy: :create
+    association :organization, factory: :organization, strategy: :create
+    notifiable { create(:article) }
   end
 end

spec/models/notification_spec.rb

@@ -517,4 +517,17 @@ RSpec.describe Notification, type: :model do
       end
     end
   end
+
+  describe "#fast_destroy_old_notifications" do
+    it "bulk deletes notifications older than 4 months by default" do
+      create_list :notification, 5
+      described_class.last.update(created_at: 5.months.ago)
+      expect { described_class.fast_destroy_old_notifications }.to change(described_class, :count).by(-1)
+    end
+
+    it "bulk deletes notifications older than a given timestamp" do
+      create_list :notification, 5
+      expect { described_class.fast_destroy_old_notifications(Time.zone.now) }.to change(described_class, :count).by(-5)
+    end
+  end
 end