feat(gl): add standalone ledger authority mode

interface/grpc/settlement.go

@@ -2,12 +2,11 @@ package grpcadapter
 
 import (
 	"context"
-	"crypto/subtle"
+	"errors"
 
 	"gl/domain/ledger"
 	ledgerv1 "gl/gen/ledger/v1"
 	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/status"
 )
 
@@ -17,6 +16,9 @@ func (h *Handler) EnqueueSettlement(ctx context.Context, request *ledgerv1.Enque
 	}
 	record, already, err := h.settlement.Enqueue(ctx, request.GetSourceService(), request.GetSourceTransactionId(), request.GetIdempotencyKey(), request.GetNetwork(), request.GetSignedTransactionXdr())
 	if err != nil {
+		if errors.Is(err, ledger.ErrModeRequired) {
+			return nil, rpcError(err)
+		}
 		return nil, status.Error(codes.InvalidArgument, err.Error())
 	}
 	return &ledgerv1.EnqueueSettlementResponse{SettlementId: record.ID, Status: string(record.Status), AlreadyExisted: already}, nil
@@ -26,9 +28,8 @@ func (h *Handler) RetrySettlement(ctx context.Context, request *ledgerv1.RetrySe
 	if h.settlement == nil {
 		return nil, status.Error(codes.Unimplemented, "settlement is not configured")
 	}
-	values := metadata.ValueFromIncomingContext(ctx, "x-admin-token")
-	if h.adminToken == "" || len(values) != 1 || subtle.ConstantTimeCompare([]byte(values[0]), []byte(h.adminToken)) != 1 {
-		return nil, status.Error(codes.PermissionDenied, "invalid administrative token")
+	if err := h.requireAdmin(ctx); err != nil {
+		return nil, err
 	}
 	record, err := h.settlement.RetryByOperator(ctx, request.GetSettlementId(), request.GetActorId(), request.GetReason())
 	if err != nil {