fix: patch dataloader to propagate context to new fiber

Author: xuanduc987

instrumentation/graphql/lib/opentelemetry/instrumentation/graphql/instrumentation.rb

@@ -27,6 +27,8 @@ class Instrumentation < OpenTelemetry::Instrumentation::Base
             require_relative 'tracers/graphql_trace'
             install_new_tracer(config)
           end
+
+          patch
         end
 
         present do
@@ -96,6 +98,13 @@ def install_new_tracer(config = {})
             end
           end
         end
+
+        def patch
+          return if gem_version < Gem::Version.new('2.1.8')
+
+          require_relative 'patches/dataloader'
+          ::GraphQL::Dataloader.prepend(Patches::Dataloader)
+        end
       end
     end
   end

instrumentation/graphql/lib/opentelemetry/instrumentation/graphql/patches/dataloader.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# Copyright The OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Instrumentation
+    module GraphQL
+      module Patches
+        # Patches GraphQL::Dataloader to propagate context to new fiber
+        module Dataloader
+          def spawn_fiber(&block)
+            ctx = OpenTelemetry::Context.current
+            super do
+              OpenTelemetry::Context.with_current(ctx, &block)
+            end
+          end
+        end
+      end
+    end
+  end
+end