1 files changed, 46 insertions, 0 deletions
diff --git a/lib/gitlab/tracing/rack_middleware.rb b/lib/gitlab/tracing/rack_middleware.rb
new file mode 100644
index 00000000000..e6a31293f7b
--- /dev/null
+++ b/lib/gitlab/tracing/rack_middleware.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require 'opentracing'
+
+module Gitlab
+  module Tracing
+    class RackMiddleware
+      include Common
+
+      REQUEST_METHOD = 'REQUEST_METHOD'
+
+      def initialize(app)
+        @app = app
+      end
+
+      def call(env)
+        method = env[REQUEST_METHOD]
+
+        context = tracer.extract(OpenTracing::FORMAT_RACK, env)
+        tags = {
+          'component' =>   'rack',
+          'span.kind' =>   'server',
+          'http.method' => method,
+          'http.url' =>    self.class.build_sanitized_url_from_env(env)
+        }
+
+        in_tracing_span(operation_name: "http:#{method}", child_of: context, tags: tags) do |span|
+          @app.call(env).tap do |status_code, _headers, _body|
+            span.set_tag('http.status_code', status_code)
+          end
+        end
+      end
+
+      # Generate a sanitized (safe) request URL from the rack environment
+      def self.build_sanitized_url_from_env(env)
+        request = ActionDispatch::Request.new(env)
+
+        original_url = request.original_url
+        uri = URI.parse(original_url)
+        uri.query = request.filtered_parameters.to_query if uri.query.present?
+
+        uri.to_s
+      end
+    end
+  end
+end