1 files changed, 41 insertions, 0 deletions
diff --git a/app/models/concerns/awareness.rb b/app/models/concerns/awareness.rb
new file mode 100644
index 00000000000..da87d87e838
--- /dev/null
+++ b/app/models/concerns/awareness.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module Awareness
+  extend ActiveSupport::Concern
+
+  KEY_NAMESPACE = "gitlab:awareness"
+  private_constant :KEY_NAMESPACE
+
+  def join(session)
+    session.join(self)
+
+    nil
+  end
+
+  def leave(session)
+    session.leave(self)
+
+    nil
+  end
+
+  def session_ids
+    with_redis do |redis|
+      redis
+        .smembers(user_sessions_key)
+        # converts session ids from (internal) integer to hex presentation
+        .map { |key| key.to_i.to_s(16) }
+    end
+  end
+
+  private
+
+  def user_sessions_key
+    "#{KEY_NAMESPACE}:user:#{id}:sessions"
+  end
+
+  def with_redis
+    Gitlab::Redis::SharedState.with do |redis|
+      yield redis if block_given?
+    end
+  end
+end