[deploy] Copy ActiveRecord methods from fastly-rails (#7145)

* Add comment referencing Fastly gem

* Create purgable concern and include it

* Typo: deprecate --> deprecated

* Include Purgable on the Tag model

* Rename Purgable to Purgeable

* Reorganize fastly and service methods in Purgeable

* Add and fix specs

* Add development env guards

app/labor/cache_buster.rb

@@ -7,6 +7,17 @@ module CacheBuster
   ].freeze
 
   def self.bust(path)
+    # TODO: (Alex Smith) - It would be "nice to have" the ability to use the
+    # Fastly gem here instead of custom API calls. We'd want to keep thread
+    # safety in mind. We'll also want to consider making this modular for those
+    # who don't want to use Fastly at all.
+    #
+    # Instead of HTTP calls, we could do:
+    # fastly  = Fastly.new(api_key: ApplicationConfig["FASTLY_API_KEY"])
+    # service = Fastly::Service.new({ id: ApplicationConfig["FASTLY_SERVICE_ID"] }, fastly)
+    # fastly.purge(path)
+    #
+    # https://github.com/fastly/fastly-ruby#efficient-purging
     return unless Rails.env.production?
 
     HTTParty.post("https://api.fastly.com/purge/https://#{ApplicationConfig['APP_DOMAIN']}#{path}",

app/models/application_record.rb

@@ -1,6 +1,8 @@
 class ApplicationRecord < ActiveRecord::Base
   self.abstract_class = true
 
+  include Purgeable
+
   QUERY_ESTIMATED_COUNT = <<~SQL.squish.freeze
     SELECT (
       (reltuples / GREATEST(relpages, 1)) *

app/models/concerns/purgeable.rb

@@ -0,0 +1,74 @@
+# Copied from the deprecated fastly-rails gem
+# https://github.com/fastly/fastly-rails/blob/master/lib/fastly-rails/active_record/surrogate_key.rb
+#
+# This concern handles purge and purge_all calls to purge the edge cache (Fastly)
+module Purgeable
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    def purge_all
+      return if Rails.env.development?
+
+      service.purge_by_key(table_key)
+    end
+
+    def soft_purge_all
+      return if Rails.env.development?
+
+      service.purge_by_key(table_key, true)
+    end
+
+    def table_key
+      table_name
+    end
+
+    def fastly
+      return if Rails.env.development?
+
+      Fastly.new(api_key: ApplicationConfig["FASTLY_API_KEY"])
+    end
+
+    def service
+      return if Rails.env.development?
+
+      Fastly::Service.new({ id: ApplicationConfig["FASTLY_SERVICE_ID"] }, fastly)
+    end
+  end
+
+  # Instance methods
+  def record_key
+    "#{table_key}/#{id}"
+  end
+
+  def table_key
+    self.class.table_key
+  end
+
+  def purge
+    return if Rails.env.development?
+
+    service.purge_by_key(record_key)
+  end
+
+  def soft_purge
+    return if Rails.env.development?
+
+    service.purge_by_key(record_key, true)
+  end
+
+  def purge_all
+    self.class.purge_all
+  end
+
+  def soft_purge_all
+    self.class.soft_purge_all
+  end
+
+  def fastly
+    self.class.fastly
+  end
+
+  def service
+    self.class.service
+  end
+end

app/models/tag.rb

@@ -39,6 +39,9 @@ class Tag < ActsAsTaggableOn::Tag
   SEARCH_SERIALIZER = Search::TagSerializer
   SEARCH_CLASS = Search::Tag
 
+  # This model doesn't inherit from ApplicationRecord so this has to be included
+  include Purgeable
+
   # possible social previews templates for articles with a particular tag
   def self.social_preview_templates
     Rails.root.join("app/views/social_previews/articles").children.map { |ch| File.basename(ch, ".html.erb") }

spec/models/concerns/purgeable_spec.rb

@@ -0,0 +1,101 @@
+require "rails_helper"
+
+class PurgeableModel
+  include Purgeable
+
+  def self.table_name
+    "purgeables"
+  end
+
+  def id
+    1
+  end
+end
+
+RSpec.describe Purgeable do
+  let(:model_class) { PurgeableModel }
+  let(:purgeable_model) { model_class.new }
+  let(:fastly_service) { instance_double(Fastly::Service) }
+
+  before do
+    allow(Fastly::Service).to receive(:new).and_return(fastly_service)
+  end
+
+  describe "class methods" do
+    it "calls .purge_by_key with table_key in purge_all" do
+      allow(fastly_service).to receive(:purge_by_key)
+      model_class.purge_all
+      expect(fastly_service).to have_received(:purge_by_key).with(model_class.table_key)
+    end
+
+    it "calls .purge_by_key with table_key and true in soft_purge_all" do
+      allow(fastly_service).to receive(:purge_by_key)
+      model_class.soft_purge_all
+      expect(fastly_service).to have_received(:purge_by_key).with(model_class.table_key, true)
+    end
+
+    it "returns table_name with table_key" do
+      expect(model_class.table_key).to eq(model_class.table_name)
+    end
+
+    it "returns a Fastly object" do
+      fastly = instance_double(Fastly)
+      allow(Fastly).to receive(:new).and_return(fastly)
+      model_class.fastly
+      expect(Fastly).to have_received(:new)
+    end
+
+    it "returns a Fastly::Service object" do
+      model_class.service
+      expect(Fastly::Service).to have_received(:new)
+    end
+  end
+
+  describe "instance methods" do
+    it "returns a record key" do
+      expect(purgeable_model.record_key).to eq("purgeables/1")
+    end
+
+    it "returns a table_key" do
+      allow(model_class).to receive(:table_key).and_return(model_class.table_name)
+      expect(purgeable_model.table_key).to eq(model_class.table_name)
+      expect(model_class).to have_received(:table_key)
+    end
+
+    it "calls .purge_by_key with record_key in purge" do
+      allow(fastly_service).to receive(:purge_by_key)
+      purgeable_model.purge
+      expect(fastly_service).to have_received(:purge_by_key).with(purgeable_model.record_key)
+    end
+
+    it "calls .purge_by_key with record_key and true in soft_purge" do
+      allow(fastly_service).to receive(:purge_by_key)
+      purgeable_model.soft_purge
+      expect(fastly_service).to have_received(:purge_by_key).with(purgeable_model.record_key, true)
+    end
+
+    it "calls purge_all class method" do
+      allow(model_class).to receive(:purge_all)
+      purgeable_model.purge_all
+      expect(model_class).to have_received(:purge_all)
+    end
+
+    it "calls soft_purge_all class method" do
+      allow(model_class).to receive(:soft_purge_all)
+      purgeable_model.soft_purge_all
+      expect(model_class).to have_received(:soft_purge_all)
+    end
+
+    it "calls the fastly class method" do
+      allow(model_class).to receive(:fastly)
+      purgeable_model.fastly
+      expect(model_class).to have_received(:fastly)
+    end
+
+    it "calls the service class method" do
+      allow(model_class).to receive(:service)
+      purgeable_model.service
+      expect(model_class).to have_received(:service)
+    end
+  end
+end

spec/rails_helper.rb

@@ -113,7 +113,7 @@ RSpec.configure do |config|
     stub_request(:any, /res.cloudinary.com/).to_rack("dsdsdsds")
 
     stub_request(:post, /api.fastly.com/).
-      to_return(status: 200, body: "", headers: {})
+      to_return(status: 200, body: "".to_json, headers: {})
 
     stub_request(:post, /api.bufferapp.com/).
       to_return(status: 200, body: { fake_text: "so fake" }.to_json, headers: {})