Split up the Docker Pull and Docker Create events.

lib/coursemology/evaluator/logging/docker_log_subscriber.rb

@@ -1,4 +1,8 @@
 class Coursemology::Evaluator::Logging::DockerLogSubscriber < ActiveSupport::LogSubscriber
+  def pull(event)
+    info "#{color("Docker Pull (#{event.duration.round(1)}ms)", GREEN)} #{event.payload[:image]}"
+  end
+
   def create(event)
     info "#{color("Docker Create (#{event.duration.round(1)}ms)", MAGENTA)} "\
       "#{event.payload[:image]} => #{event.payload[:container].id}"

lib/coursemology/evaluator/services/evaluate_programming_package_service.rb

@@ -44,9 +44,13 @@ def execute
 
   def create_container(image)
     image_identifier = "coursemology/evaluator-image-#{image}"
+    ActiveSupport::Notifications.instrument('pull.docker.evaluator.coursemology',
+                                            image: image_identifier) do
+      Docker::Image.create('fromImage' => image_identifier)
+    end
+
     ActiveSupport::Notifications.instrument('create.docker.evaluator.coursemology',
                                             image: image_identifier) do |payload|
-      Docker::Image.create('fromImage' => image_identifier)
       payload[:container] = Docker::Container.create('Image' => image_identifier)
     end
   end

spec/coursemology/evaluator/services/evaluate_programming_package_service_spec.rb

@@ -25,6 +25,11 @@
       container
     end
 
+    it 'instruments the pull' do
+      expect { subject.send(:create_container, image) }.to \
+        instrument_notification('pull.docker.evaluator.coursemology')
+    end
+
     it 'instruments the creation' do
       expect { subject.send(:create_container, image) }.to \
         instrument_notification('create.docker.evaluator.coursemology')