1 files changed, 41 insertions, 0 deletions
diff --git a/app/models/concerns/cron_schedulable.rb b/app/models/concerns/cron_schedulable.rb
new file mode 100644
index 00000000000..beb3a09c119
--- /dev/null
+++ b/app/models/concerns/cron_schedulable.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module CronSchedulable
+  extend ActiveSupport::Concern
+  include Schedulable
+
+  ##
+  # The `next_run_at` column is set to the actual execution date of worker that
+  # triggers the schedule. This way, a schedule like `*/1 * * * *` won't be triggered
+  # in a short interval when the worker runs irregularly by Sidekiq Memory Killer.
+  def set_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
+
+  private
+
+  def ideal_next_run_from(start_time)
+    next_time_from(start_time, cron, cron_timezone)
+  end
+
+  def cron_worker_next_run_from(start_time)
+    next_time_from(start_time, worker_cron_expression, Time.zone.name)
+  end
+
+  def next_time_from(start_time, cron, cron_timezone)
+    Gitlab::Ci::CronParser
+      .new(cron, cron_timezone)
+      .next_time_from(start_time)
+  end
+
+  def worker_cron_expression
+    raise NotImplementedError
+  end
+end