Switch to parent context propagation in grpc server

lib/sagittarius/middleware/grpc/open_telemetry.rb

@@ -27,19 +27,21 @@ def execute(method:, call:, **_, &block)
           method_name = found_method&.to_s || '(unknown)'
           rpc_method = "#{service_name}/#{method_name}"
 
-          links = extract_remote_span_links(call)
+          parent_context = extract_parent_context(call)
           attributes = build_attributes(rpc_method)
 
-          self.class.tracer.in_span(rpc_method, links: links, kind: :server, attributes: attributes) do |span|
-            result = block.call
-            record_success(span)
-            result
-          rescue ::GRPC::BadStatus => e
-            record_grpc_error(span, e)
-            raise
-          rescue StandardError => e
-            record_exception(span, e)
-            raise
+          ::OpenTelemetry::Context.with_current(parent_context) do
+            self.class.tracer.in_span(rpc_method, kind: :server, attributes: attributes) do |span|
+              result = block.call
+              record_success(span)
+              result
+            rescue ::GRPC::BadStatus => e
+              record_grpc_error(span, e)
+              raise
+            rescue StandardError => e
+              record_exception(span, e)
+              raise
+            end
           end
         end
 
@@ -74,15 +76,10 @@ def record_exception(span, error)
           span.record_exception(error)
         end
 
-        def extract_remote_span_links(call)
-          extracted_context = ::OpenTelemetry.propagation.extract(call.metadata)
-          remote_span_context = ::OpenTelemetry::Trace.current_span(extracted_context).context
-
-          return [] unless remote_span_context.valid?
-
-          [::OpenTelemetry::Trace::Link.new(remote_span_context)]
+        def extract_parent_context(call)
+          ::OpenTelemetry.propagation.extract(call.metadata)
         rescue StandardError
-          []
+          ::OpenTelemetry::Context.current
         end
       end
     end

spec/lib/sagittarius/middleware/grpc/open_telemetry_spec.rb

@@ -128,32 +128,29 @@ def test(_msg, _call)
     end
   end
 
-  describe 'span links' do
+  describe 'parent context propagation' do
     context 'when valid trace context is present' do
       let(:metadata) do
         { 'traceparent' => '00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01' }
       end
 
-      it 'passes a link to the remote span context' do
+      it 'sets the remote span as parent' do
         # rubocop:disable Lint/EmptyBlock -- the block is part of the api and needs to be given
         interceptor.request_response(request: request, call: call, method: method) {}
         # rubocop:enable Lint/EmptyBlock
 
-        expect(span.links.size).to eq(1)
-
-        link = span.links.first
-        expect(link.span_context.hex_trace_id).to eq('0af7651916cd43dd8448eb211c80319c')
-        expect(link.span_context.hex_span_id).to eq('b7ad6b7169203331')
+        expect(span.hex_trace_id).to eq('0af7651916cd43dd8448eb211c80319c')
+        expect(span.hex_parent_span_id).to eq('b7ad6b7169203331')
       end
     end
 
     context 'when no trace context is present' do
-      it 'passes no links' do
+      it 'creates a new root span' do
         # rubocop:disable Lint/EmptyBlock -- the block is part of the api and needs to be given
         interceptor.request_response(request: request, call: call, method: method) {}
         # rubocop:enable Lint/EmptyBlock
 
-        expect(span.links).to be_nil.or be_empty
+        expect(span.hex_parent_span_id).to eq('0000000000000000')
       end
     end
   end