Do not schedule pipelines if the user can't

When the owner of a pipelines schedule was either blocked or was removed
from the project, the pipeline schedular would still schedule the
pipeline.

This would than fail however, given the user had no access to the
project and it contents. However, a better way to handle it would be to
not schedule it at all. Furthermore, from now on, such schedules will be
deactivated so the schedule worker can ignore it on the next runs.

app/models/ci/pipeline_schedule.rb

@@ -28,10 +28,18 @@ module Ci
       !active?
     end
 
+    def deactivate!
+      update_attribute(:active, false)
+    end
+
     def importing_or_inactive?
       importing? || inactive?
     end
 
+    def runnable_by_owner?
+      Ability.allowed?(owner, :create_pipeline, project)
+    end
+
     def set_next_run_at
       self.next_run_at = Gitlab::Ci::CronParser.new(cron, cron_timezone).next_time_from(Time.now)
     end

app/workers/pipeline_schedule_worker.rb

@@ -3,8 +3,14 @@ class PipelineScheduleWorker
   include CronjobQueue
 
   def perform
-    Ci::PipelineSchedule.active.where("next_run_at < ?", Time.now).find_each do |schedule|
+    Ci::PipelineSchedule.active.where("next_run_at < ?", Time.now)
+      .preload(:owner, :project).find_each do |schedule|
       begin
+        unless schedule.runnable_by_owner?
+          schedule.deactivate!
+          next
+        end
+
         Ci::CreatePipelineService.new(schedule.project,
                                       schedule.owner,
                                       ref: schedule.ref)

changelogs/unreleased/zj-pipeline-schedule-owner.yml

+---
+title: Add foreign key for pipeline schedule owner
+merge_request: 11233
+author:

doc/ci/pipeline_schedules.md

@@ -35,6 +35,10 @@ To change the Sidekiq worker's frequency, you have to edit the `trigger_schedule
 value in your `gitlab.rb` and restart GitLab. The Sidekiq worker's configuration
 on GiLab.com is able to be looked up at [here](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/config/gitlab.yml.example#L185).
 - Cron notation is parsed by [Rufus-Scheduler](https://github.com/jmettraux/rufus-scheduler).
+- When the owner of the schedule does not have the ability to create pipelines
+anymore, due to e.g. being blocked or removed from the project, the schedule is
+deactivated. Another user can take ownership and activate it, so the schedule is
+run again.
 
 [ce-10533]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10533
 [ce-10853]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10853

spec/workers/pipeline_schedule_worker_spec.rb

@@ -11,18 +11,17 @@ describe PipelineScheduleWorker do
   end
 
   before do
-    project.add_master(user)
-
     stub_ci_pipeline_to_return_yaml_file
-  end
 
-  context 'when there is a scheduled pipeline within next_run_at' do
-    let(:next_run_at) { 2.days.ago }
+    pipeline_schedule.update_column(:next_run_at, 1.day.ago)
+  end
 
+  context 'when the schedule is runnable by the user' do
     before do
-      pipeline_schedule.update_column(:next_run_at, next_run_at)
+      project.add_master(user)
     end
 
+    context 'when there is a scheduled pipeline within next_run_at' do
       it 'creates a new pipeline' do
         expect { subject }.to change { project.pipelines.count }.by(1)
       end
@@ -35,17 +34,31 @@ describe PipelineScheduleWorker do
 
       it 'sets the schedule on the pipeline' do
         subject
+
         expect(project.pipelines.last.pipeline_schedule).to eq(pipeline_schedule)
       end
     end
 
     context 'inactive schedule' do
       before do
-      pipeline_schedule.update(active: false)
+        pipeline_schedule.deactivate!
       end
 
       it 'does not creates a new pipeline' do
         expect { subject }.not_to change { project.pipelines.count }
       end
     end
+  end
+
+  context 'when the schedule is not runnable by the user' do
+    it 'deactivates the schedule' do
+      subject
+
+      expect(pipeline_schedule.reload.active).to be_falsy
+    end
+
+    it 'does not schedule a pipeline' do
+      expect { subject }.not_to change { project.pipelines.count }
+    end
+  end
 end