Merge branch 'spread-runner-last-updated-at' into 'master'

Spread out runner contacted_at updates

This is meant to prevent having too many concurrent UPDATE requests
caused by runners checking in.

See merge request !1722

CHANGELOG

@@ -23,6 +23,9 @@ v 8.2.0 (unreleased)
   - Add "added", "modified" and "removed" properties to commit object in webhook
   - Rename "Back to" links to "Go to" because its not always a case it point to place user come from
 
+v 8.1.3
+  - Spread out runner contacted_at updates
+
 v 8.1.1
   - Fix cloning Wiki repositories via HTTP (Stan Hu)
   - Add migration to remove satellites directory

lib/ci/api/helpers.rb

@@ -16,7 +16,9 @@ module Ci
       end
 
       def update_runner_last_contact
-        if current_runner.contacted_at.nil? || Time.now - current_runner.contacted_at >= UPDATE_RUNNER_EVERY
+        # Use a random threshold to prevent beating DB updates
+        contacted_at_max_age = UPDATE_RUNNER_EVERY + Random.rand(UPDATE_RUNNER_EVERY)
+        if current_runner.contacted_at.nil? || Time.now - current_runner.contacted_at >= contacted_at_max_age
           current_runner.update_attributes(contacted_at: Time.now)
         end
       end