1 files changed, 43 insertions, 19 deletions

diff --git a/app/services/ci/register_build_service.rb b/app/services/ci/register_build_service.rb
index 74b5ebf372b..6f03bf2be13 100644
--- a/app/services/ci/register_build_service.rb
+++ b/app/services/ci/register_build_service.rb
@@ -2,48 +2,72 @@ module Ci
   # This class responsible for assigning
   # proper pending build to runner on runner API request
   class RegisterBuildService
-    def execute(current_runner)
-      builds = Ci::Build.pending.unstarted
+    include Gitlab::CurrentSettings
 
+    attr_reader :runner
+
+    Result = Struct.new(:build, :valid?)
+
+    def initialize(runner)
+      @runner = runner
+    end
+
+    def execute
       builds =
-        if current_runner.shared?
-          builds.
-            # don't run projects which have not enabled shared runners and builds
-            joins(:project).where(projects: { shared_runners_enabled: true }).
-            joins('LEFT JOIN project_features ON ci_builds.gl_project_id = project_features.project_id').
-
-            # this returns builds that are ordered by number of running builds
-            # we prefer projects that don't use shared runners at all
-            joins("LEFT JOIN (#{running_builds_for_shared_runners.to_sql}) AS project_builds ON ci_builds.gl_project_id=project_builds.gl_project_id").
-            where('project_features.builds_access_level IS NULL or project_features.builds_access_level > 0').
-            order('COALESCE(project_builds.running_builds, 0) ASC', 'ci_builds.id ASC')
+        if runner.shared?
+          builds_for_shared_runner
         else
-          # do run projects which are only assigned to this runner (FIFO)
-          builds.where(project: current_runner.projects.with_builds_enabled).order('created_at ASC')
+          builds_for_specific_runner
         end
 
       build = builds.find do |build|
-        current_runner.can_pick?(build)
+        runner.can_pick?(build)
       end
 
       if build
         # In case when 2 runners try to assign the same build, second runner will be declined
         # with StateMachines::InvalidTransition or StaleObjectError when doing run! or save method.
-        build.runner_id = current_runner.id
+        build.runner_id = runner.id
         build.run!
       end
 
-      build
+      Result.new(build, true)
 
     rescue StateMachines::InvalidTransition, ActiveRecord::StaleObjectError
-      nil
+      Result.new(build, false)
     end
 
     private
 
+    def builds_for_shared_runner
+      new_builds.
+        # don't run projects which have not enabled shared runners and builds
+        joins(:project).where(projects: { shared_runners_enabled: true }).
+        joins('LEFT JOIN project_features ON ci_builds.gl_project_id = project_features.project_id').
+        where('project_features.builds_access_level IS NULL or project_features.builds_access_level > 0').
+
+        # Implement fair scheduling
+        # this returns builds that are ordered by number of running builds
+        # we prefer projects that don't use shared runners at all
+        joins("LEFT JOIN (#{running_builds_for_shared_runners.to_sql}) AS project_builds ON ci_builds.gl_project_id=project_builds.gl_project_id").
+        order('COALESCE(project_builds.running_builds, 0) ASC', 'ci_builds.id ASC')
+    end
+
+    def builds_for_specific_runner
+      new_builds.where(project: runner.projects.with_builds_enabled).order('created_at ASC')
+    end
+
     def running_builds_for_shared_runners
       Ci::Build.running.where(runner: Ci::Runner.shared).
         group(:gl_project_id).select(:gl_project_id, 'count(*) AS running_builds')
     end
+
+    def new_builds
+      Ci::Build.pending.unstarted
+    end
+
+    def shared_runner_build_limits_feature_enabled?
+      ENV['DISABLE_SHARED_RUNNER_BUILD_MINUTES_LIMIT'].to_s != 'true'
+    end
   end
 end