module Ci # This class responsible for assigning # proper pending build to runner on runner API request class RegisterJobService include Gitlab::CurrentSettings attr_reader :runner Result = Struct.new(:build, :valid?) def initialize(runner) @runner = runner end def execute builds = if runner.shared? builds_for_shared_runner else builds_for_specific_runner end valid = true builds.find do |build| next unless runner.can_pick?(build) begin # 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 = runner.id build.run! return Result.new(build, true) rescue StateMachines::InvalidTransition, ActiveRecord::StaleObjectError # We are looping to find another build that is not conflicting # It also indicates that this build can be picked and passed to runner. # If we don't do it, basically a bunch of runners would be competing for a build # and thus we will generate a lot of 409. This will increase # the number of generated requests, also will reduce significantly # how many builds can be picked by runner in a unit of time. # In case we hit the concurrency-access lock, # we still have to return 409 in the end, # to make sure that this is properly handled by runner. valid = false end end Result.new(nil, valid) 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.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.project_id=project_builds.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(:project_id).select(: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