Instantiate collaborators in publishing services

We can still inject them when we have the need to have a different
serializer and storage client.

ee/app/services/status_page/publish_base_service.rb

@@ -2,26 +2,44 @@
 
 module StatusPage
   class PublishBaseService
-    def initialize(project:, storage_client:, serializer:)
+    include Gitlab::Utils::StrongMemoize
+
+    def initialize(project:)
       @project = project
-      @storage_client = storage_client
-      @serializer = serializer
     end
 
     def execute(*args)
       return error_feature_not_available unless feature_available?
+      return error_no_storage_client unless storage_client
 
       publish(*args)
     end
 
     private
 
-    attr_reader :project, :storage_client, :serializer
+    attr_reader :project
 
     def publish(*args)
       raise NotImplementedError
     end
 
+    def storage_client
+      strong_memoize(:strong_memoize) do
+        project.status_page_setting&.storage_client
+      end
+    end
+
+    def serializer
+      strong_memoize(:serializer) do
+        # According to development/reusing_abstractions.html#abstractions
+        # serializers can only be used from controllers.
+        # For the Status Page however, we generate JSON in background jobs.
+        # rubocop: disable CodeReuse/Serializer
+        StatusPage::IncidentSerializer.new
+        # rubocop: enable CodeReuse/Serializer
+      end
+    end
+
     def feature_available?
       project.status_page_setting&.enabled?
     end
@@ -55,6 +73,10 @@ module StatusPage
       error('Feature not available')
     end
 
+    def error_no_storage_client
+      error('No storage client available. Is the status page setting activated?')
+    end
+
     def success(payload = {})
       ServiceResponse.success(payload: payload)
     end

ee/spec/services/status_page/publish_details_service_spec.rb

@@ -4,25 +4,17 @@ require 'spec_helper'
 
 describe StatusPage::PublishDetailsService do
   let_it_be(:project, refind: true) { create(:project) }
-  let(:storage_client) { instance_double(StatusPage::Storage::S3Client) }
-  let(:serializer) { instance_double(StatusPage::IncidentSerializer) }
   let(:issue) { instance_double(Issue) }
   let(:user_notes) { double(:user_notes) }
   let(:incident_id) { 1 }
   let(:key) { StatusPage::Storage.details_path(incident_id) }
   let(:content) { { id: incident_id } }
-  let(:content_json) { content.to_json }
 
-  let(:service) do
-    described_class.new(
-      project: project, storage_client: storage_client, serializer: serializer
-    )
-  end
+  let(:service) { described_class.new(project: project) }
 
   subject(:result) { service.execute(issue, user_notes) }
 
   describe '#execute' do
-    context 'when license is available' do
     before do
       allow(serializer).to receive(:represent_details).with(issue, user_notes)
         .and_return(content)
@@ -39,5 +31,4 @@ describe StatusPage::PublishDetailsService do
       end
     end
   end
-  end
 end

ee/spec/services/status_page/publish_list_service_spec.rb

@@ -4,23 +4,15 @@ require 'spec_helper'
 
 describe StatusPage::PublishListService do
   let_it_be(:project, refind: true) { create(:project) }
-  let(:storage_client) { instance_double(StatusPage::Storage::S3Client) }
-  let(:serializer) { instance_double(StatusPage::IncidentSerializer) }
   let(:issues) { [instance_double(Issue)] }
   let(:key) { StatusPage::Storage.list_path }
   let(:content) { [{ some: :content }] }
-  let(:content_json) { content.to_json }
 
-  let(:service) do
-    described_class.new(
-      project: project, storage_client: storage_client, serializer: serializer
-    )
-  end
+  let(:service) { described_class.new(project: project) }
 
   subject(:result) { service.execute(issues) }
 
   describe '#execute' do
-    context 'when license is available' do
     before do
       allow(serializer).to receive(:represent_list).with(issues)
         .and_return(content)
@@ -28,5 +20,4 @@ describe StatusPage::PublishListService do
 
     include_examples 'publish incidents'
   end
-  end
 end

ee/spec/support/shared_examples/status_page/publish_shared_examples.rb

 # frozen_string_literal: true
 
 RSpec.shared_examples 'publish incidents' do
-  let_it_be(:status_page_setting) do
-    create(:status_page_setting, :enabled, project: project)
+  let(:status_page_setting_enabled) { true }
+  let(:storage_client) { instance_double(StatusPage::Storage::S3Client) }
+  let(:serializer) { instance_double(StatusPage::IncidentSerializer) }
+  let(:content_json) { content.to_json }
+
+  let(:status_page_setting) do
+    instance_double(StatusPageSetting, enabled?: status_page_setting_enabled,
+                    storage_client: storage_client)
   end
 
   before do
     stub_licensed_features(status_page: true)
+
+    allow(project).to receive(:status_page_setting)
+      .and_return(status_page_setting)
+    allow(StatusPage::IncidentSerializer).to receive(:new)
+      .and_return(serializer)
   end
 
   shared_examples 'feature is not available' do
-    it 'returns feature not available error' do
-      expect(result).to be_error
-      expect(result.message).to eq('Feature not available')
-    end
   end
 
   context 'when upload succeeds' do
@@ -66,27 +73,12 @@ RSpec.shared_examples 'publish incidents' do
     end
   end
 
-  context 'when feature is not available' do
-    before do
-      stub_licensed_features(status_page: false)
-    end
-
-    it_behaves_like 'feature is not available'
-  end
-
-  context 'when status page setting is disabled' do
-    before do
-      status_page_setting.update!(enabled: false)
-    end
-
-    it_behaves_like 'feature is not available'
-  end
+  context 'when status page setting is not enabled' do
+    let(:status_page_setting_enabled) { false }
 
-  context 'when feature flag is disabled' do
-    before do
-      stub_feature_flags(status_page: false)
+    it 'returns feature not available error' do
+      expect(result).to be_error
+      expect(result.message).to eq('Feature not available')
     end
-
-    it_behaves_like 'feature is not available'
   end
 end