[Hidden] Display a friendly message when a background report times out

.env.development

@@ -11,3 +11,9 @@ OFN_REDIS_URL="redis://localhost:6379/1"
 OFN_REDIS_JOBS_URL="redis://localhost:6379/2"
 
 SITE_URL="0.0.0.0:3000"
+
+# Deactivate rack-timeout in development.
+# https://github.com/zombocom/rack-timeout#configuring
+RACK_TIMEOUT_SERVICE_TIMEOUT="0"
+RACK_TIMEOUT_WAIT_TIMEOUT="0"
+RACK_TIMEOUT_WAIT_OVERTIME="0"

Gemfile

@@ -92,6 +92,7 @@ gem 'gmaps4rails'
 gem 'mimemagic', '> 0.3.5'
 gem 'paper_trail', '~> 12.1'
 gem 'rack-rewrite'
+gem 'rack-timeout'
 gem 'roadie-rails'
 
 gem 'hiredis'
@@ -141,7 +142,6 @@ gem "private_address_check"
 
 group :production, :staging do
   gem 'ddtrace'
-  gem 'rack-timeout'
   gem 'sd_notify' # For better Systemd process management. Used by Puma.
 end
 

app/controllers/admin/reports_controller.rb

@@ -26,6 +26,8 @@ def show
       else
         show_report
       end
+    rescue Timeout::Error
+      render_timeout_error
     end
 
     private
@@ -36,6 +38,7 @@ def export_report
 
     def show_report
       assign_view_data
+      @table = render_report_as(:html) if render_data?
       render "show"
     end
 
@@ -45,7 +48,6 @@ def assign_view_data
       @report_subtype = report_subtype
       @report_title = report_title
       @rendering_options = rendering_options
-      @table = render_report_as(:html) if render_data?
       @data = Reporting::FrontendData.new(spree_current_user)
     end
 
@@ -58,13 +60,33 @@ def render_report_as(format)
         job = ReportJob.perform_later(
           report_class, spree_current_user, params, format
         )
-        sleep 1 until job.done?
+        Timeout.timeout(max_wait_time) do
+          sleep 1 until job.done?
+        end
 
         # This result has been rendered by Rails in safe mode already.
         job.result.html_safe # rubocop:disable Rails/OutputSafety
       else
         @report.render_as(format)
       end
     end
+
+    def render_timeout_error
+      assign_view_data
+      @error = ".report_taking_longer"
+      render "show"
+    end
+
+    def max_wait_time
+      # This value is used by rack-timeout and nginx, usually 30 seconds in
+      # staging and production:
+      server_timeout = ENV.fetch("RACK_TIMEOUT_SERVICE_TIMEOUT", "15").to_f
+
+      # Zero disables the timeout:
+      return 0 if server_timeout.zero?
+
+      # We want to time out earlier than nginx:
+      server_timeout - 2.seconds
+    end
   end
 end

app/views/admin/reports/show.html.haml

@@ -18,7 +18,8 @@
 .report__header.print-hidden
   - if @report.message.present?
     %p.report__message= @report.message
-  - if request.post?
+  - if request.post? && !@error
     %button.btn-print.icon-print{ onclick: "window.print()"}= t(:report_print)
 
+= t(@error) if @error
 = @table

config/locales/en.yml

@@ -1438,6 +1438,11 @@ en:
       pack_by_customer: Pack By Customer
       pack_by_supplier: Pack By Supplier
       pack_by_product: Pack By Product
+      show:
+        report_taking_longer: >
+          Sorry, this report took too long to process.
+          It may contain a lot of data or we are busy with other reports.
+          You can try again later.
       revenues_by_hub:
         name: Revenues By Hub
         description: Revenues by hub

spec/system/admin/reports_spec.rb

@@ -44,6 +44,19 @@
       click_button "Go"
       expect(page).to have_content "EMAIL FIRST NAME"
     end
+
+    it "displays a friendly timeout message" do
+      ActiveJob::Base.queue_adapter.perform_enqueued_jobs = false
+      login_as_admin_and_visit admin_report_path(
+        report_type: :customers, report_subtype: :mailing_list
+      )
+      expect(ENV).to receive(:fetch).with("RACK_TIMEOUT_SERVICE_TIMEOUT", "15")
+        .and_return("-1") # Negative values time out immediately.
+
+      click_button "Go"
+
+      expect(page).to have_content "this report took too long"
+    end
   end
 
   describe "Can access Customers reports and generate customers report" do