1 files changed, 36 insertions, 0 deletions
diff --git a/lib/gitlab/health_checks/puma_check.rb b/lib/gitlab/health_checks/puma_check.rb
new file mode 100644
index 00000000000..7aafe29fbae
--- /dev/null
+++ b/lib/gitlab/health_checks/puma_check.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module HealthChecks
+    # This check can only be run on Puma `master` process
+    class PumaCheck
+      extend SimpleAbstractCheck
+
+      class << self
+        private
+
+        def metric_prefix
+          'puma_check'
+        end
+
+        def successful?(result)
+          result > 0
+        end
+
+        def check
+          return unless defined?(::Puma)
+
+          stats = Puma.stats
+          stats = JSON.parse(stats)
+
+          # If `workers` is missing this means that
+          # Puma server is running in single mode
+          stats.fetch('workers', 1)
+        rescue NoMethodError
+          # server is not ready
+          0
+        end
+      end
+    end
+  end
+end