subscription.rb in ddtrace-0.29.0

- old
+ new

@@ -3,20 +3,23 @@
     module ActiveSupport
       module Notifications
         # An ActiveSupport::Notification subscription that wraps events with tracing.
         class Subscription
           attr_accessor \
-            :tracer,
             :span_name,
             :options
 
           def initialize(tracer, span_name, options, &block)
             raise ArgumentError, 'Must be given a block!' unless block_given?
             @tracer = tracer
             @span_name = span_name
             @options = options
             @handler = Handler.new(&block)
             @callbacks = Callbacks.new
+          end
+
+          def tracer
+            @tracer.is_a?(Proc) ? @tracer.call : @tracer
           end
 
           # ActiveSupport 3.x calls this
           def call(name, start, finish, id, payload)
             start_span(name, id, payload, start)