Run do_master_restart callback on server start

We want to call master_restart callback on start too - this callback
is used for cleaning up prometheus files. It has been added to
Omnibus already:
https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/3350

So make sure that Unicorn example configs are up-to-date and that
the same callback is called for Puma too.

1 files changed, 11 insertions, 4 deletions

diff --git a/config/initializers/7_prometheus_metrics.rb b/config/initializers/7_prometheus_metrics.rb
index 68f8487d377..54cdefc2a10 100644
--- a/config/initializers/7_prometheus_metrics.rb
+++ b/config/initializers/7_prometheus_metrics.rb
@@ -43,14 +43,21 @@ if !Rails.env.test? && Gitlab::Metrics.prometheus_metrics_enabled?
   end
 end
 
-Gitlab::Cluster::LifecycleEvents.on_master_restart do
+def cleanup_prometheus_multiproc_dir
   # The following is necessary to ensure stale Prometheus metrics don't
   # accumulate over time. It needs to be done in this hook as opposed to
   # inside an init script to ensure metrics files aren't deleted after new
   # unicorn workers start after a SIGUSR2 is received.
-  prometheus_multiproc_dir = ENV['prometheus_multiproc_dir']
-  if prometheus_multiproc_dir
-    old_metrics = Dir[File.join(prometheus_multiproc_dir, '*.db')]
+  if dir = ::Prometheus::Client.configuration.multiprocess_files_dir
+    old_metrics = Dir[File.join(dir, '*.db')]
     FileUtils.rm_rf(old_metrics)
   end
 end
+
+Gitlab::Cluster::LifecycleEvents.on_master_start do
+  cleanup_prometheus_multiproc_dir
+end
+
+Gitlab::Cluster::LifecycleEvents.on_master_restart do
+  cleanup_prometheus_multiproc_dir
+end