1 files changed, 57 insertions, 0 deletions
diff --git a/lib/gitlab/runtime.rb b/lib/gitlab/runtime.rb
new file mode 100644
index 00000000000..33b7b68e64e
--- /dev/null
+++ b/lib/gitlab/runtime.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module Gitlab
+  # Provides routines to identify the current runtime as which the application
+  # executes, such as whether it is an application server and which one.
+  module Runtime
+    AmbiguousProcessError = Class.new(StandardError)
+    UnknownProcessError = Class.new(StandardError)
+
+    class << self
+      def identify
+        matches = []
+        matches << :puma if puma?
+        matches << :unicorn if unicorn?
+        matches << :console if console?
+        matches << :sidekiq if sidekiq?
+
+        if matches.one?
+          matches.first
+        elsif matches.none?
+          raise UnknownProcessError.new(
+            "Failed to identify runtime for process #{Process.pid} (#{$0})"
+          )
+        else
+          raise AmbiguousProcessError.new(
+            "Ambiguous runtime #{matches} for process #{Process.pid} (#{$0})"
+          )
+        end
+      end
+
+      def puma?
+        !!defined?(::Puma)
+      end
+
+      # For unicorn, we need to check for actual server instances to avoid false positives.
+      def unicorn?
+        !!(defined?(::Unicorn) && defined?(::Unicorn::HttpServer))
+      end
+
+      def sidekiq?
+        !!(defined?(::Sidekiq) && Sidekiq.server?)
+      end
+
+      def console?
+        !!defined?(::Rails::Console)
+      end
+
+      def web_server?
+        puma? || unicorn?
+      end
+
+      def multi_threaded?
+        puma? || sidekiq?
+      end
+    end
+  end
+end