Run reports in background

app/controllers/admin/reports_controller.rb

@@ -22,6 +22,13 @@ module Admin
     def show
       @report = report_class.new(spree_current_user, params, render: render_data?)
 
+      @background_reports = OpenFoodNetwork::FeatureToggle
+                              .enabled?(:background_reports, spree_current_user)
+
+      if @background_reports && request.post?
+        return background(report_format)
+      end
+
       if params[:report_format].present?
         export_report
       else
@@ -34,12 +41,12 @@ module Admin
     private
 
     def export_report
-      send_data render_report_as(report_format), filename: report_filename
+      send_data @report.render_as(report_format), filename: report_filename
     end
 
     def show_report
       assign_view_data
-      @table = render_report_as(:html) if render_data?
+      @table = @report.render_as(:html) if render_data?
       render "show"
     end
 
@@ -56,21 +63,21 @@ module Admin
       request.post?
     end
 
-    def render_report_as(format)
-      if OpenFoodNetwork::FeatureToggle.enabled?(:background_reports, spree_current_user)
-        @blob = ReportBlob.create_for_upload_later!(report_filename)
-        ReportJob.perform_later(
-          report_class, spree_current_user, params, format, @blob
-        )
-        Timeout.timeout(max_wait_time) do
-          sleep 1 until @blob.content_stored?
-        end
+    def background(format)
+      @blob = ReportBlob.create_for_upload_later!(report_filename)
 
-        # This result has been rendered by Rails in safe mode already.
-        @blob.result.html_safe # rubocop:disable Rails/OutputSafety
-      else
-        @report.render_as(format)
-      end
+      ReportJob.perform_later(
+        report_class, spree_current_user, params, format, @blob, SessionChannel.for_request(request)
+      )
+
+      render cable_ready: cable_car.
+        inner_html(
+          selector: "#report-table",
+          html: render_to_string(partial: "admin/reports/loading")
+        ).scroll_into_view(
+          selector: "#report-table",
+          block: "start"
+        )
     end
 
     def render_timeout_error
@@ -84,17 +91,5 @@ module Admin
       end
       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/jobs/application_job.rb

@@ -7,4 +7,11 @@ class ApplicationJob < ActiveJob::Base
 
   # Most jobs are safe to ignore if the underlying records are no longer available
   # discard_on ActiveJob::DeserializationError
+
+  private
+
+  def enable_active_storage_urls
+    ActiveStorage::Current.url_options ||=
+      Rails.application.config.action_controller.default_url_options
+  end
 end

app/jobs/report_job.rb

@@ -2,9 +2,14 @@
 
 # Renders a report and stores it in a given blob.
 class ReportJob < ApplicationJob
+  include CableReady::Broadcaster
+  delegate :render, to: ActionController::Base
+
+  before_perform :enable_active_storage_urls
+
   NOTIFICATION_TIME = 5.seconds
 
-  def perform(report_class, user, params, format, blob)
+  def perform(report_class, user, params, format, blob, channel = nil)
     start_time = Time.zone.now
 
     report = report_class.new(user, params, render: true)
@@ -14,6 +19,8 @@ class ReportJob < ApplicationJob
     execution_time = Time.zone.now - start_time
 
     email_result(user, blob) if execution_time > NOTIFICATION_TIME
+
+    broadcast_result(channel, format, blob) if channel
   end
 
   def email_result(user, blob)
@@ -22,4 +29,17 @@ class ReportJob < ApplicationJob
       blob: blob,
     ).report_ready.deliver_later
   end
+
+  def broadcast_result(channel, format, blob)
+    cable_ready[channel].inner_html(
+      selector: "#report-table",
+      html: actioncable_content(format, blob)
+    ).broadcast
+  end
+
+  def actioncable_content(format, blob)
+    return blob.result if format.to_sym == :html
+
+    render(partial: "admin/reports/download", locals: { file_url: blob.expiring_service_url })
+  end
 end

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

@@ -0,0 +1,2 @@
+.download
+  = link_to t("admin.reports.download.button"), file_url, target: "_blank", class: "button icon icon-file"

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

@@ -0,0 +1,2 @@
+.loading
+  = render partial: "components/admin_spinner"

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

@@ -3,7 +3,9 @@
 
 - content_for :minimal_js, true if @background_reports
 
-= form_for @report.search, :url => url_for do |f|
+- options = @background_reports ? { data: { remote: "true" } } : {}
+
+= form_for @report.search, { url: url_for }.merge(options) do |f|
   %fieldset.no-border-bottom.print-hidden
     %legend{ align: 'center'}= t(:report_filters)
     = render partial: "admin/reports/filters/#{@report_type}", locals: { f: f }
@@ -24,4 +26,6 @@
     %button.btn-print.icon-print{ onclick: "window.print()"}= t(:report_print)
 
 = t(@error, link: link_to(t(".report_link_label"), @error_url)) if @error
-= @table
+
+#report-table
+  = @table

app/webpacker/css/admin/reports.scss

@@ -60,3 +60,24 @@ table.report__table {
   margin: 0 !important;
   width: 120px;
 }
+
+#report-table {
+  margin-bottom: 4em;
+
+  .loading, .download {
+    text-align: center;
+    height: 2em;
+    padding: 4em;
+    width: 100%;
+
+    .spinner {
+      font-size: 4em;
+      color: $spree-blue;
+      opacity: 0.3;
+    }
+
+    .button {
+      font-size: 1.25em;
+    }
+  }
+}

config/locales/en.yml

@@ -1469,6 +1469,8 @@ en:
       pack_by_customer: Pack By Customer
       pack_by_supplier: Pack By Supplier
       pack_by_product: Pack By Product
+      download:
+        button: "Download Report"
       show:
         report_taking_longer: >
           Sorry, this report took too long to process.