feat(taiko-client): introduce --epoch.allowZeroInterval flag (#17727)

Co-authored-by: gavin <[email protected]>

packages/taiko-client/cmd/flags/proposer.go

@@ -82,9 +82,9 @@ var (
 		Value:    0,
 		EnvVars:  []string{"EPOCH_MIN_TX_LIST_BYTES"},
 	}
-	MinTip = &cli.Uint64Flag{
+	MinTip = &cli.Float64Flag{
 		Name:     "epoch.minTip",
-		Usage:    "Minimum tip for a transaction to propose",
+		Usage:    "Minimum tip (in GWei) for a transaction to propose",
 		Category: proposerCategory,
 		Value:    0,
 		EnvVars:  []string{"EPOCH_MIN_TIP"},
@@ -96,6 +96,13 @@ var (
 		Value:    0,
 		EnvVars:  []string{"EPOCH_MIN_PROPOSING_INTERNAL"},
 	}
+	AllowZeroInterval = &cli.Uint64Flag{
+		Name:     "epoch.allowZeroInterval",
+		Usage:    "If set, after this many epochs, proposer will allow propose zero tip transactions once",
+		Category: proposerCategory,
+		Value:    0,
+		EnvVars:  []string{"EPOCH_ALLOW_ZERO_INTERVAL"},
+	}
 	// Proposing metadata related.
 	ExtraData = &cli.StringFlag{
 		Name:     "extraData",
@@ -164,6 +171,7 @@ var ProposerFlags = MergeFlags(CommonFlags, []cli.Flag{
 	MinTxListBytes,
 	MinTip,
 	MinProposingInternal,
+	AllowZeroInterval,
 	MaxProposedTxListsPerEpoch,
 	ProverEndpoints,
 	OptimisticTierFee,

packages/taiko-client/proposer/config.go

@@ -34,6 +34,7 @@ type Config struct {
 	MinTxListBytes             uint64
 	MinTip                     uint64
 	MinProposingInternal       time.Duration
+	AllowZeroInterval          uint64
 	MaxProposedTxListsPerEpoch uint64
 	ProposeBlockTxGasLimit     uint64
 	ProverEndpoints            []*url.URL
@@ -94,6 +95,11 @@ func NewConfigFromCliContext(c *cli.Context) (*Config, error) {
 		return nil, err
 	}
 
+	minTip, err := utils.GWeiToWei(c.Float64(flags.MinTip.Name))
+	if err != nil {
+		return nil, err
+	}
+
 	return &Config{
 		ClientConfig: &rpc.ClientConfig{
 			L1Endpoint:        c.String(flags.L1WSEndpoint.Name),
@@ -114,9 +120,10 @@ func NewConfigFromCliContext(c *cli.Context) (*Config, error) {
 		LocalAddressesOnly:         c.Bool(flags.TxPoolLocalsOnly.Name),
 		MinGasUsed:                 c.Uint64(flags.MinGasUsed.Name),
 		MinTxListBytes:             c.Uint64(flags.MinTxListBytes.Name),
-		MinTip:                     c.Uint64(flags.MinTip.Name),
+		MinTip:                     minTip.Uint64(),
 		MinProposingInternal:       c.Duration(flags.MinProposingInternal.Name),
 		MaxProposedTxListsPerEpoch: c.Uint64(flags.MaxProposedTxListsPerEpoch.Name),
+		AllowZeroInterval:          c.Uint64(flags.AllowZeroInterval.Name),
 		ProposeBlockTxGasLimit:     c.Uint64(flags.TxGasLimit.Name),
 		ProverEndpoints:            proverEndpoints,
 		OptimisticTierFee:          optimisticTierFee,

packages/taiko-client/proposer/proposer.go

@@ -53,6 +53,7 @@ type Proposer struct {
 	protocolConfigs *bindings.TaikoDataConfig
 
 	lastProposedAt time.Time
+	totalEpochs    uint64
 
 	txmgr *txmgr.SimpleTxManager
 
@@ -177,6 +178,7 @@ func (p *Proposer) eventLoop() {
 		// proposing interval timer has been reached
 		case <-p.proposingTimer.C:
 			metrics.ProposerProposeEpochCounter.Add(1)
+			p.totalEpochs++
 
 			// Attempt a proposing operation
 			if err := p.ProposeOp(p.ctx); err != nil {
@@ -194,6 +196,13 @@ func (p *Proposer) Close(_ context.Context) {
 
 // fetchPoolContent fetches the transaction pool content from L2 execution engine.
 func (p *Proposer) fetchPoolContent(filterPoolContent bool) ([]types.Transactions, error) {
+	minTip := p.MinTip
+	// If `--epoch.allowZeroInterval` flag is set, allow proposing zero tip transactions once when
+	// the total epochs number is divisible by the flag value.
+	if p.AllowZeroInterval > 0 && p.totalEpochs%p.AllowZeroInterval == 0 {
+		minTip = 0
+	}
+
 	// Fetch the pool content.
 	preBuiltTxList, err := p.rpc.GetPoolContent(
 		p.ctx,
@@ -202,7 +211,7 @@ func (p *Proposer) fetchPoolContent(filterPoolContent bool) ([]types.Transaction
 		rpc.BlockMaxTxListBytes,
 		p.LocalAddresses,
 		p.MaxProposedTxListsPerEpoch,
-		p.MinTip,
+		minTip,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("failed to fetch transaction pool content: %w", err)