Add support for engine_exchangeCapabilities

beacon-chain/execution/engine_client.go

@@ -30,6 +30,20 @@ import (
 	"go.opencensus.io/trace"
 )
 
+var (
+	supportedEngineEndpoints = []string{
+		NewPayloadMethod,
+		NewPayloadMethodV2,
+		ForkchoiceUpdatedMethod,
+		ForkchoiceUpdatedMethodV2,
+		GetPayloadMethod,
+		GetPayloadMethodV2,
+		ExchangeTransitionConfigurationMethod,
+		GetPayloadBodiesByHashV1,
+		GetPayloadBodiesByRangeV1,
+	}
+)
+
 const (
 	// NewPayloadMethod v1 request string for JSON-RPC.
 	NewPayloadMethod = "engine_newPayloadV1"
@@ -53,6 +67,8 @@ const (
 	GetPayloadBodiesByHashV1 = "engine_getPayloadBodiesByHashV1"
 	// GetPayloadBodiesByRangeV1 v1 request string for JSON-RPC.
 	GetPayloadBodiesByRangeV1 = "engine_getPayloadBodiesByRangeV1"
+	// ExchangeCapabilities request string for JSON-RPC.
+	ExchangeCapabilities = "engine_exchangeCapabilities"
 	// Defines the seconds before timing out engine endpoints with non-block execution semantics.
 	defaultEngineTimeout = time.Second
 )
@@ -278,6 +294,35 @@ func (s *Service) ExchangeTransitionConfiguration(
 	return nil
 }
 
+func (s *Service) ExchangeCapabilities(ctx context.Context) ([]string, error) {
+	if !features.Get().EnableOptionalEngineMethods {
+		return nil, errors.New("optional engine methods not enabled")
+	}
+	ctx, span := trace.StartSpan(ctx, "powchain.engine-api-client.ExchangeCapabilities")
+	defer span.End()
+
+	result := &pb.ExchangeCapabilities{}
+	err := s.rpcClient.CallContext(ctx, &result, ExchangeCapabilities, supportedEngineEndpoints)
+
+	var unsupported []string
+	for _, s1 := range supportedEngineEndpoints {
+		supported := false
+		for _, s2 := range result.SupportedMethods {
+			if s1 == s2 {
+				supported = true
+				break
+			}
+		}
+		if !supported {
+			unsupported = append(unsupported, s1)
+		}
+	}
+	if len(unsupported) != 0 {
+		log.Warnf("Please update, detected the following unsupported engine methods: %s", unsupported)
+	}
+	return result.SupportedMethods, handleRPCError(err)
+}
+
 // GetTerminalBlockHash returns the valid terminal block hash based on total difficulty.
 //
 // Spec code:

beacon-chain/execution/engine_client_test.go

@@ -2320,3 +2320,75 @@ func TestCapella_PayloadBodiesByRange(t *testing.T) {
 		}
 	})
 }
+
+func Test_ExchangeCapabilities(t *testing.T) {
+	resetFn := features.InitWithReset(&features.Flags{
+		EnableOptionalEngineMethods: true,
+	})
+	defer resetFn()
+	t.Run("empty response works", func(t *testing.T) {
+		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/json")
+			defer func() {
+				require.NoError(t, r.Body.Close())
+			}()
+			exchangeCapabilities := &pb.ExchangeCapabilities{}
+			resp := map[string]interface{}{
+				"jsonrpc": "2.0",
+				"id":      1,
+				"result":  exchangeCapabilities,
+			}
+			err := json.NewEncoder(w).Encode(resp)
+			require.NoError(t, err)
+		}))
+		ctx := context.Background()
+
+		rpcClient, err := rpc.DialHTTP(srv.URL)
+		require.NoError(t, err)
+
+		service := &Service{}
+		service.rpcClient = rpcClient
+
+		results, err := service.ExchangeCapabilities(ctx)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(results))
+
+		for _, item := range results {
+			require.NotNil(t, item)
+		}
+	})
+	t.Run("list of items", func(t *testing.T) {
+		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/json")
+			defer func() {
+				require.NoError(t, r.Body.Close())
+			}()
+			exchangeCapabilities := &pb.ExchangeCapabilities{
+				SupportedMethods: []string{"A", "B", "C"},
+			}
+
+			resp := map[string]interface{}{
+				"jsonrpc": "2.0",
+				"id":      1,
+				"result":  exchangeCapabilities,
+			}
+			err := json.NewEncoder(w).Encode(resp)
+			require.NoError(t, err)
+		}))
+		ctx := context.Background()
+
+		rpcClient, err := rpc.DialHTTP(srv.URL)
+		require.NoError(t, err)
+
+		service := &Service{}
+		service.rpcClient = rpcClient
+
+		results, err := service.ExchangeCapabilities(ctx)
+		require.NoError(t, err)
+		require.Equal(t, 3, len(results))
+
+		for _, item := range results {
+			require.NotNil(t, item)
+		}
+	})
+}

proto/engine/v1/execution_engine.proto

@@ -177,3 +177,7 @@ message Blob {
 	// Each blob consists of `BLS_FIELD_ELEMENT`(32) multiplies `FIELD_ELEMENTS_PER_BLOB`(4096)
 	bytes data = 1 [(ethereum.eth.ext.ssz_size) = "131072"]; // 32 * 4096 = 131072
 }
+
+message ExchangeCapabilities {
+	repeated string supported_methods = 1;
+}