Add flag with which dynamic job priorities can be enabled

jobs/cloud_controller_ng/spec

@@ -370,6 +370,10 @@ properties:
     description: "The longest this job can take before it is cancelled"
   cc.jobs.priorities:
     description: "List of hashes containing delayed jobs 'display_name' and its desired priority. This will overwrite the default priority of ccng"
+  cc.jobs.enable_dynamic_job_priorities:
+    description: "When enabled, the priority of asynchronous jobs will be increased by 1 for each active asynchronous job for that user. 
+                  This prevents that a single user, who creates many asynchronous jobs, slows down job execution for other users."
+    default: false
 
   cc.temporary_disable_deployments:
     description: "Do not allow the API client to create app deployments (temporary)"

jobs/cloud_controller_ng/templates/cloud_controller_ng.yml.erb

@@ -80,6 +80,7 @@ reserved_private_domains: <%= p("cc.reserved_private_domains", nil) %>
 disable_private_domain_cross_space_context_path_route_sharing: <%= p("cc.disable_private_domain_cross_space_context_path_route_sharing", false) %>
 
 jobs:
+  enable_dynamic_job_priorities: <%= p("cc.jobs.enable_dynamic_job_priorities") %>
   global:
     timeout_in_seconds: <%= p("cc.jobs.global.timeout_in_seconds") %>
   <% if_p("cc.jobs.blobstore_delete.timeout_in_seconds") do |timeout| %>

spec/cloud_controller_ng/cloud_controller_ng_spec.rb

@@ -670,6 +670,26 @@ module Test
               end
             end
           end
+
+          describe 'enable_dynamic_job_priorities' do
+            context "when 'enable_dynamic_job_priorities' is set to true" do
+              before do
+                merged_manifest_properties['cc']['jobs'] = { 'enable_dynamic_job_priorities' => true }
+              end
+
+              it 'renders true into ccng config' do
+                template_hash = YAML.safe_load(template.render(merged_manifest_properties, consumes: links))
+                expect(template_hash['jobs']['enable_dynamic_job_priorities']).to be(true)
+              end
+            end
+
+            context "when 'enable_dynamic_job_priorities' is not set" do
+              it 'renders false into ccng config' do
+                template_hash = YAML.safe_load(template.render(merged_manifest_properties, consumes: links))
+                expect(template_hash['jobs']['enable_dynamic_job_priorities']).to be(false)
+              end
+            end
+          end
         end
       end
     end