Fix pipeline schedule edge casefix-pipeline-schedule-edge-case

If pipeline schedule is to run at the exact same time with when cron
worker runs, the pipeline schedule will not be executed at the
ideal timing.

We fix this bug by comparing the exact matching of ideal and
cron worker's next run at.

1 files changed, 17 insertions, 6 deletions

diff --git a/app/models/ci/pipeline_schedule.rb b/app/models/ci/pipeline_schedule.rb
index 6a4241c94bc..ba8cea0cea9 100644
--- a/app/models/ci/pipeline_schedule.rb
+++ b/app/models/ci/pipeline_schedule.rb
@@ -55,15 +55,20 @@ module Ci
     # This way, a schedule like `*/1 * * * *` won't be triggered in a short interval
     # when PipelineScheduleWorker runs irregularly by Sidekiq Memory Killer.
     def set_next_run_at
-      self.next_run_at = Gitlab::Ci::CronParser.new(Settings.cron_jobs['pipeline_schedule_worker']['cron'],
-                                                    Time.zone.name)
-                                               .next_time_from(ideal_next_run_at)
+      now = Time.zone.now
+      ideal_next_run = ideal_next_run_from(now)
+
+      self.next_run_at = if ideal_next_run == cron_worker_next_run_from(now)
+                           ideal_next_run
+                         else
+                           cron_worker_next_run_from(ideal_next_run)
+                         end
     end
 
     def schedule_next_run!
       save! # with set_next_run_at
     rescue ActiveRecord::RecordInvalid
-      update_attribute(:next_run_at, nil) # update without validation
+      update_column(:next_run_at, nil) # update without validation
     end
 
     def job_variables
@@ -72,9 +77,15 @@ module Ci
 
     private
 
-    def ideal_next_run_at
+    def ideal_next_run_from(start_time)
       Gitlab::Ci::CronParser.new(cron, cron_timezone)
-        .next_time_from(Time.zone.now)
+                            .next_time_from(start_time)
+    end
+
+    def cron_worker_next_run_from(start_time)
+      Gitlab::Ci::CronParser.new(Settings.cron_jobs['pipeline_schedule_worker']['cron'],
+                                Time.zone.name)
+                            .next_time_from(start_time)
     end
   end
 end