feat: add eth blob support to proposer (#938)

* add eth blob support to proposer

* allow no DA provider configured

Author: jorgemmsilva

synd-withdrawals/synd-proposer/pkg/config/config.go

@@ -24,6 +24,7 @@ type Config struct {
 	AppchainRPCURL   string `json:"AppchainRPCURL"`
 	EnclaveRPCURL    string `json:"EnclaveRPCURL"`
 	EigenRPCUrl      string `json:"EigenRPCUrl"`
+	BeaconRPCURL     string `json:"BeaconRPCURL"`
 
 	PrivateKey             *ecdsa.PrivateKey `json:"-"`
 	PollingInterval        time.Duration     `json:"PollingInterval"`
@@ -52,7 +53,8 @@ var Keys = map[string]struct {
 	"settlement-chain-id":         {"Settlement Chain ID", "", true},
 	"sequencing-rpc-url":          {"Sequencing RPC URL", "", true},
 	"appchain-rpc-url":            {"Appchain RPC URL", "", true},
-	"eigen-rpc-url":               {"EigenDA RPC URL", "", true},
+	"eigen-rpc-url":               {"EigenDA RPC URL", "", false},
+	"beacon-rpc-url":              {"Beacon Chain RPC URL for blob fetching", "", false},
 	"enclave-rpc-url":             {"Enclave RPC URL", "", true},
 	"tee-module-contract-address": {"TEE Module Contract Address", "", true},
 	"appchain-bridge-address":     {"Appchain Bridge Address", "", true},
@@ -121,6 +123,7 @@ func LoadConfig() (*Config, error) {
 		AppchainRPCURL:           viper.GetString("appchain-rpc-url"),
 		EnclaveRPCURL:            viper.GetString("enclave-rpc-url"),
 		EigenRPCUrl:              viper.GetString("eigen-rpc-url"),
+		BeaconRPCURL:             viper.GetString("beacon-rpc-url"),
 		TeeModuleContractAddress: common.HexToAddress(viper.GetString("tee-module-contract-address")),
 		AppchainBridgeAddress:    common.HexToAddress(viper.GetString("appchain-bridge-address")),
 		PrivateKey:               privateKey,

synd-withdrawals/synd-proposer/pkg/proposer.go

@@ -28,6 +28,7 @@ import (
 	"github.com/offchainlabs/nitro/daprovider"
 	"github.com/offchainlabs/nitro/eigenda"
 	"github.com/offchainlabs/nitro/solgen/go/bridgegen"
+	"github.com/offchainlabs/nitro/util/headerreader"
 	"github.com/pkg/errors"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
@@ -86,15 +87,6 @@ func NewProposer(ctx context.Context, cfg *config.Config, metrics *metrics.Metri
 		msg, wrappedErr := logger.WrapErrorWithMsg("Failed to create settlement provider", err)
 		log.Fatal().Stack().Err(wrappedErr).Msg(msg)
 	}
-	eigenClient, err := eigenda.NewEigenDA(&eigenda.EigenDAConfig{
-		Enable: true,
-		Rpc:    cfg.EigenRPCUrl,
-	})
-	if err != nil {
-		msg, wrappedErr := logger.WrapErrorWithMsg("Failed to create Eigen provider", err)
-		log.Fatal().Stack().Err(wrappedErr).Msg(msg)
-	}
-
 	settlementAuth, err := bind.NewKeyedTransactorWithChainID(cfg.PrivateKey, big.NewInt(int64(cfg.SettlementChainID)))
 	if err != nil {
 		msg, wrappedErr := logger.WrapErrorWithMsg("Failed to create settlement transactor", err)
@@ -114,7 +106,7 @@ func NewProposer(ctx context.Context, cfg *config.Config, metrics *metrics.Metri
 		EnclaveClient:    enclaveClient,
 		SettlementClient: settlementClient,
 		SettlementAuth:   *settlementAuth,
-		DapReaders:       []daprovider.Reader{eigenda.NewReaderForEigenDA(eigenClient)},
+		DapReaders:       buildDapReaders(ctx, cfg, ethereumClient),
 		TeeModule:        teeModule,
 		Metrics:          metrics,
 
@@ -645,3 +637,41 @@ func (p *Proposer) makeTransactOptsCopy(ctx context.Context) *bind.TransactOpts
 	copy.Nonce = nil         // ensure fresh nonce lookup
 	return &copy
 }
+
+// buildDapReaders constructs the list of DA provider readers based on configuration
+func buildDapReaders(ctx context.Context, cfg *config.Config, ethereumClient *ethclient.Client) []daprovider.Reader {
+	var readers []daprovider.Reader
+
+	if cfg.EigenRPCUrl != "" {
+		eigenClient, err := eigenda.NewEigenDA(&eigenda.EigenDAConfig{
+			Enable: true,
+			Rpc:    cfg.EigenRPCUrl,
+		})
+		if err != nil {
+			msg, wrappedErr := logger.WrapErrorWithMsg("Failed to create Eigen provider", err)
+			log.Fatal().Stack().Err(wrappedErr).Msg(msg)
+		}
+		readers = append(readers, eigenda.NewReaderForEigenDA(eigenClient))
+	}
+
+	if cfg.BeaconRPCURL != "" {
+		blobClient, err := headerreader.NewBlobClient(headerreader.BlobClientConfig{
+			BeaconUrl: cfg.BeaconRPCURL,
+		}, ethereumClient)
+		if err != nil {
+			msg, wrappedErr := logger.WrapErrorWithMsg("Failed to create blob client", err)
+			log.Fatal().Stack().Err(wrappedErr).Msg(msg)
+		}
+		if err = blobClient.Initialize(ctx); err != nil {
+			msg, wrappedErr := logger.WrapErrorWithMsg("Failed to initialize blob client", err)
+			log.Fatal().Stack().Err(wrappedErr).Msg(msg)
+		}
+		readers = append(readers, daprovider.NewReaderForBlobReader(blobClient))
+	}
+
+	if len(readers) == 0 {
+		log.Warn().Msg("No DA provider has been configured (eigen-rpc-url or beacon-rpc-url)")
+	}
+
+	return readers
+}