Clean Sidekiq metrics from multiproc dir on start

After moving the multiproc dir cleanup into `config.ru`:`warmup`, we
stopped cleaning Sidekiq metrics dir which is not correct.
This MR intended to fix that. More details:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/31668

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/prometheus/cleanup_multiproc_dir_service.rb b/lib/prometheus/cleanup_multiproc_dir_service.rb
new file mode 100644
index 00000000000..6418b4de166
--- /dev/null
+++ b/lib/prometheus/cleanup_multiproc_dir_service.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module Prometheus
+  class CleanupMultiprocDirService
+    include Gitlab::Utils::StrongMemoize
+
+    def execute
+      FileUtils.rm_rf(old_metrics) if old_metrics
+    end
+
+    private
+
+    def old_metrics
+      strong_memoize(:old_metrics) do
+        Dir[File.join(multiprocess_files_dir, '*.db')] if multiprocess_files_dir
+      end
+    end
+
+    def multiprocess_files_dir
+      ::Prometheus::Client.configuration.multiprocess_files_dir
+    end
+  end
+end