popm: add static fee option

cmd/popmd/popmd.go

@@ -79,6 +79,18 @@ var (
 			Help:         "the bitcoin url to connect to; it's either a tbc or blockstream url",
 			Print:        config.PrintAll,
 		},
+		"POPM_FEE_OVERRIDE": config.Config{
+			Value:        &cfg.StaticFee,
+			DefaultValue: false,
+			Help:         "if popm should override fee estimation and use a static fee",
+			Print:        config.PrintAll,
+		},
+		"POPM_FEE_AMOUNT": config.Config{
+			Value:        &cfg.StaticFeeAmount,
+			DefaultValue: uint(1),
+			Help:         "static fee amount in sats/byte (requires POPM_FEE_OVERRIDE=true)",
+			Print:        config.PrintAll,
+		},
 	}
 )
 

service/popm/popm.go

@@ -16,12 +16,14 @@ import (
 	"github.com/btcsuite/btcd/btcutil/hdkeychain"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	btcmempool "github.com/btcsuite/btcd/mempool"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/juju/loggo"
 	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/hemilabs/heminetwork/api/gethapi"
+	"github.com/hemilabs/heminetwork/api/tbcapi"
 	"github.com/hemilabs/heminetwork/bitcoin/wallet"
 	"github.com/hemilabs/heminetwork/bitcoin/wallet/gozer"
 	"github.com/hemilabs/heminetwork/bitcoin/wallet/gozer/blockstream"
@@ -51,6 +53,9 @@ const (
 	defaultL2KeystoneMaxAge       = 4 * time.Hour
 	defaultL2KeystonePollTimeout  = 13 * time.Second
 	defaultL2KeystoneRetryTimeout = 15 * time.Second
+
+	// convert btcd minimum fee from sat/kB to sat/byte
+	minRelayFee = uint(btcmempool.DefaultMinRelayTxFee) / 1000
 )
 
 var log = loggo.GetLogger("popm")
@@ -73,6 +78,8 @@ type Config struct {
 	PrometheusListenAddress string
 	PrometheusNamespace     string
 	RetryMineThreshold      uint
+	StaticFee               bool
+	StaticFeeAmount         uint
 
 	// cooked settings, do not export
 	opgethReconnectTimeout time.Duration
@@ -164,6 +171,11 @@ func NewServer(cfg *Config) (*Server, error) {
 		workC:          make(chan struct{}, 2),
 	}
 
+	if cfg.StaticFee && cfg.StaticFeeAmount < minRelayFee {
+		return nil, fmt.Errorf("static fee set to %v, minimum is %v",
+			cfg.StaticFeeAmount, minRelayFee)
+	}
+
 	switch strings.ToLower(cfg.Network) {
 	case "mainnet":
 		s.params = &chaincfg.MainNetParams
@@ -259,14 +271,9 @@ func (s *Server) createKeystoneTx(ctx context.Context, ks *hemi.L2Keystone) (*wi
 	}
 	scriptHash := vinzclortho.ScriptHashFromScript(payToScript)
 
-	// Estimate BTC fees.
-	feeEstimates, err := s.gozer.FeeEstimates(ctx)
-	if err != nil {
-		return nil, fmt.Errorf("fee estimates: %w", err)
-	}
-	feeAmount, err := gozer.FeeByConfirmations(s.cfg.BitcoinConfirmations, feeEstimates)
+	feeAmount, err := s.getFee(ctx)
 	if err != nil {
-		return nil, fmt.Errorf("fee by confirmations: %w", err)
+		return nil, err
 	}
 
 	// Retrieve available UTXOs for the miner.
@@ -334,6 +341,30 @@ func (s *Server) latestKeystones(ctx context.Context, count int) (*gethapi.L2Key
 	return &kr, nil
 }
 
+func (s *Server) getFee(ctx context.Context) (*tbcapi.FeeEstimate, error) {
+	log.Tracef("getFee")
+	defer log.Tracef("getFee exit")
+
+	var feeAmount *tbcapi.FeeEstimate
+	if s.cfg.StaticFee {
+		feeAmount = &tbcapi.FeeEstimate{
+			Blocks:      s.cfg.BitcoinConfirmations,
+			SatsPerByte: float64(s.cfg.StaticFeeAmount),
+		}
+	} else {
+		// Estimate BTC fees.
+		feeEstimates, err := s.gozer.FeeEstimates(ctx)
+		if err != nil {
+			return nil, fmt.Errorf("fee estimates: %w", err)
+		}
+		feeAmount, err = gozer.FeeByConfirmations(s.cfg.BitcoinConfirmations, feeEstimates)
+		if err != nil {
+			return nil, fmt.Errorf("fee by confirmations: %w", err)
+		}
+	}
+	return feeAmount, nil
+}
+
 // reconcileKeystones generates a keystones map
 func (s *Server) reconcileKeystones(ctx context.Context) (map[chainhash.Hash]*keystone, error) {
 	log.Tracef("reconcileKeystones")

service/popm/popm_test.go

@@ -334,6 +334,45 @@ func TestDisconnectedOpgeth(t *testing.T) {
 	}
 }
 
+func TestStaticFee(t *testing.T) {
+	ctx, cancel := context.WithTimeout(t.Context(), 15*time.Second)
+	defer cancel()
+
+	// Setup pop miner
+	cfg := NewDefaultConfig()
+	cfg.BitcoinSource = "tbc"
+	cfg.BitcoinSecret = "5e2deaa9f1bb2bcef294cc36513c591c5594d6b671fe83a104aa2708bc634c"
+	cfg.LogLevel = "popm=TRACE; mock=TRACE;"
+	cfg.StaticFee = true
+	cfg.StaticFeeAmount = 0
+
+	if err := loggo.ConfigureLoggers(cfg.LogLevel); err != nil {
+		t.Fatal(err)
+	}
+
+	// shouldn't allow static fee of 0
+	_, err := NewServer(cfg)
+	if err == nil {
+		t.Fatal("expected error")
+	}
+
+	cfg.StaticFeeAmount = 3
+	// shouldn't allow static fee of 0
+	s, err := NewServer(cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fee, err := s.getFee(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if fee.SatsPerByte != 3 {
+		t.Fatalf("expected fee of 3 sats/byte, got %v sats/byte", fee.SatsPerByte)
+	}
+}
+
 func messageListener(t *testing.T, expected map[string]int, errCh chan error, msgCh chan string) error {
 	for {
 		select {