Add noop block simulator

services/api/blocksim_ratelimiter.go

@@ -186,3 +186,19 @@ func SendJSONRPCRequest(client *http.Client, req jsonrpc.JSONRPCRequest, url str
 	}
 	return res, nil, nil
 }
+
+var _ IBlockSimRateLimiter = (*NoopBlockSim)(nil)
+
+type NoopBlockSim struct{}
+
+func newNoopBlockSim() *NoopBlockSim {
+	return &NoopBlockSim{}
+}
+
+func (n *NoopBlockSim) Send(context context.Context, payload *common.BuilderBlockValidationRequest, isHighPrio, fastTrack bool) (*common.BuilderBlockValidationResponse, error, error) {
+	return nil, nil, nil
+}
+
+func (n *NoopBlockSim) CurrentCounter() int64 {
+	return 0
+}

services/api/blocksim_ratelimiter_test.go

@@ -0,0 +1,16 @@
+package api
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNoopBlockSim(t *testing.T) {
+	n := newNoopBlockSim()
+	resp, err1, err2 := n.Send(context.Background(), nil, false, false)
+	require.NoError(t, err1)
+	require.NoError(t, err2)
+	require.Nil(t, resp)
+}

services/api/service.go

@@ -27,6 +27,7 @@ import (
 	"github.com/attestantio/go-eth2-client/spec"
 	"github.com/attestantio/go-eth2-client/spec/phase0"
 	"github.com/buger/jsonparser"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/flashbots/go-boost-utils/bls"
 	"github.com/flashbots/go-boost-utils/ssz"
 	"github.com/flashbots/go-boost-utils/utils"
@@ -297,6 +298,14 @@ func NewRelayAPI(opts RelayAPIOpts) (api *RelayAPI, err error) {
 		}
 	}
 
+	var blockSim IBlockSimRateLimiter
+	if opts.BlockSimURL != "" {
+		blockSim = NewBlockSimulationRateLimiter(opts.BlockSimURL)
+	} else {
+		log.Warn("Running without block simulator")
+		blockSim = newNoopBlockSim()
+	}
+
 	api = &RelayAPI{
 		opts:         opts,
 		log:          opts.Log,
@@ -311,7 +320,7 @@ func NewRelayAPI(opts RelayAPIOpts) (api *RelayAPI, err error) {
 		payloadAttributes: make(map[string]payloadAttributesHelper),
 
 		proposerDutiesResponse: &[]byte{},
-		blockSimRateLimiter:    NewBlockSimulationRateLimiter(opts.BlockSimURL),
+		blockSimRateLimiter:    blockSim,
 
 		validatorRegC:     make(chan builderApiV1.SignedValidatorRegistration, 450_000),
 		validatorUpdateCh: make(chan struct{}),