Merge pull request #1309 from Shopify/rdj/continuous-delivery-job

Update `ContinuousDeliveryJob` to account for concurrent tasks

app/jobs/shipit/continuous_delivery_job.rb

@@ -8,7 +8,10 @@ class ContinuousDeliveryJob < BackgroundJob
 
     def perform(stack)
       return unless stack.continuous_deployment?
-      return if stack.active_task?
+
+      # checks if there are any tasks running, including concurrent tasks
+      return if stack.occupied?
+
       stack.trigger_continuous_delivery
     end
   end

app/models/shipit/stack.rb

@@ -453,6 +453,14 @@ def active_task
       @active_task ||= tasks.current
     end
 
+    def occupied?
+      !!occupied
+    end
+
+    def occupied
+      @occupied ||= tasks.active.last
+    end
+
     def locked?
       lock_reason.present?
     end

test/models/shipit/stacks_test.rb

@@ -278,6 +278,36 @@ def self.deliver(event, stack, payload)
       end
     end
 
+    test "#active_task? is false if stack has a concurrent deploy in active state" do
+      @stack.trigger_deploy(shipit_commits(:third), AnonymousUser.new, force: true)
+      refute @stack.active_task?
+    end
+
+    test "#occupied? is false if stack has no deploy in either pending or running state" do
+      @stack.deploys.active.destroy_all
+      refute @stack.occupied?
+    end
+
+    test "#occupied? is false if stack has no deploy at all" do
+      @stack.deploys.destroy_all
+      refute @stack.occupied?
+    end
+
+    test "occupied? is true if stack has a concurrent deploy in active state" do
+      @stack.trigger_deploy(shipit_commits(:third), AnonymousUser.new, force: true)
+      assert @stack.occupied?
+    end
+
+    test "occupied? is true if stack has a deploy in pending state" do
+      @stack.trigger_deploy(shipit_commits(:third), AnonymousUser.new)
+      assert @stack.occupied?
+    end
+
+    test "#occupied? is true if a rollback is ongoing" do
+      shipit_deploys(:shipit_complete).trigger_rollback(AnonymousUser.new)
+      assert @stack.occupied?
+    end
+
     test "#deployable? returns true if the stack is not locked, not awaiting provision, and is not deploying" do
       @stack.deploys.destroy_all
       @stack.update!(lock_reason: nil, awaiting_provision: false)