Add mutex and retry logic to BlockInfoByNumber

BlockInfoByNumber was missing the mutex read lock and retry on error handling that all the other functions had.

packages/arb-util/ethutils/client.go

@@ -31,15 +31,12 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/rpc"
-	"github.com/rs/zerolog"
-
 	"github.com/offchainlabs/arbitrum/packages/arb-util/arblog"
 )
 
 var logger = arblog.Logger.With().Str("component", "ethutils").Logger()
 
 const maxErrCount = 5
-const errorCountError = maxErrCount * 10
 
 type ReceiptFetcher interface {
 	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
@@ -113,16 +110,9 @@ func (r *RPCEthClient) handleCallErr(err error) error {
 
 	// If we've had above a threshold number of errors, reinitialize the connection
 	if totalErrCount >= maxErrCount {
-		var partialLog *zerolog.Event
-		if totalErrCount < errorCountError {
-			partialLog = logger.Warn()
-		} else {
-			partialLog = logger.Error()
-		}
-		partialLog.
+		logger.Warn().
 			Err(err).
 			Str("url", r.url).
-			Uint64("count", totalErrCount).
 			Msg("Reconnecting to client endpoint after repeated errors")
 
 		if err := r.reconnect(); err != nil {
@@ -133,14 +123,22 @@ func (r *RPCEthClient) handleCallErr(err error) error {
 }
 
 func (r *RPCEthClient) BlockInfoByNumber(ctx context.Context, number *big.Int) (*BlockInfo, error) {
+	info, err := r.blockInfoByNumberImpl(ctx, number)
+	return info, r.handleCallErr(err)
+}
+
+func (r *RPCEthClient) blockInfoByNumberImpl(ctx context.Context, number *big.Int) (*BlockInfo, error) {
 	var raw json.RawMessage
 	var numParam string
 	if number != nil {
 		numParam = hexutil.EncodeBig(number)
 	} else {
 		numParam = "latest"
 	}
-	if err := r.rpc.CallContext(ctx, &raw, "eth_getBlockByNumber", numParam, false); err != nil {
+	r.RLock()
+	err := r.rpc.CallContext(ctx, &raw, "eth_getBlockByNumber", numParam, false)
+	r.RUnlock()
+	if err != nil {
 		return nil, err
 	}
 	if len(raw) == 0 {