Add active_jobs_limit to plans table

This is a port from EE changes where
we introduce a new limit for Plan model.

https://dev.gitlab.org/gitlab/gitlab-ee/merge_requests/1182

app/models/ci/pipeline.rb

@@ -203,6 +203,7 @@ module Ci
     scope :for_sha, -> (sha) { where(sha: sha) }
     scope :for_source_sha, -> (source_sha) { where(source_sha: source_sha) }
     scope :for_sha_or_source_sha, -> (sha) { for_sha(sha).or(for_source_sha(sha)) }
+    scope :created_after, -> (time) { where('ci_pipelines.created_at > ?', time) }
     scope :triggered_by_merge_request, -> (merge_request) do
       where(source: :merge_request_event, merge_request: merge_request)

app/services/ci/create_pipeline_service.rb

@@ -15,7 +15,8 @@ module Ci
                 Gitlab::Ci::Pipeline::Chain::Limit::Size,
                 Gitlab::Ci::Pipeline::Chain::Populate,
                 Gitlab::Ci::Pipeline::Chain::Create,
-                Gitlab::Ci::Pipeline::Chain::Limit::Activity].freeze
+                Gitlab::Ci::Pipeline::Chain::Limit::Activity,
+                Gitlab::Ci::Pipeline::Chain::Limit::JobActivity].freeze
     def execute(source, ignore_skip_ci: false, save_on_errors: true, trigger_request: nil, schedule: nil, merge_request: nil, **options, &block)
       @pipeline = Ci::Pipeline.new

db/migrate/20190816151221_add_active_jobs_limit_to_plans.rb

+# frozen_string_literal: true
+
+class AddActiveJobsLimitToPlans < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_column_with_default :plans, :active_jobs_limit, :integer, default: 0
+  end
+
+  def down
+    remove_column :plans, :active_jobs_limit
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
-ActiveRecord::Schema.define(version: 2019_08_15_093949) do
+ActiveRecord::Schema.define(version: 2019_08_16_151221) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -2500,6 +2500,7 @@ ActiveRecord::Schema.define(version: 2019_08_15_093949) do
     t.string "title"
     t.integer "active_pipelines_limit"
     t.integer "pipeline_size_limit"
+    t.integer "active_jobs_limit", default: 0
     t.index ["name"], name: "index_plans_on_name"
   end

lib/gitlab/ci/pipeline/chain/limit/job_activity.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    module Pipeline
+      module Chain
+        module Limit
+          class JobActivity < Chain::Base
+            def perform!
+              # to be overridden in EE
+            end
+
+            def break?
+              false # to be overridden in EE
+            end
+          end
+        end
+      end
+    end
+  end
+end