Create framework for build prerequisites

Introduces the concept of Prerequisites for a CI build.
If a build has unmet prerequisites it will go through the
:preparing state before being made available to a runner.

There are no actual prerequisites yet, so current
behaviour is unchanged.

1 files changed, 16 insertions, 0 deletions

diff --git a/app/workers/ci/build_prepare_worker.rb b/app/workers/ci/build_prepare_worker.rb
new file mode 100644
index 00000000000..1a35a74ae53
--- /dev/null
+++ b/app/workers/ci/build_prepare_worker.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module Ci
+  class BuildPrepareWorker
+    include ApplicationWorker
+    include PipelineQueue
+
+    queue_namespace :pipeline_processing
+
+    def perform(build_id)
+      Ci::Build.find_by_id(build_id).try do |build|
+        Ci::PrepareBuildService.new(build).execute
+      end
+    end
+  end
+end