feat: support decimal payout amount

cmd/server.go

@@ -24,7 +24,7 @@ var (
 	proxyCntFlag = flag.Int("proxycount", 0, "Count of reverse proxies in front of the server")
 	versionFlag  = flag.Bool("version", false, "Print version number")
 
-	payoutFlag   = flag.Int("faucet.amount", 1, "Number of Ethers to transfer per user request")
+	payoutFlag   = flag.Float64("faucet.amount", 1, "Number of Ethers to transfer per user request")
 	intervalFlag = flag.Int("faucet.minutes", 1440, "Number of minutes to wait between funding rounds")
 	netnameFlag  = flag.String("faucet.name", "testnet", "Network name to display on the frontend")
 	symbolFlag   = flag.String("faucet.symbol", "ETH", "Token symbol to display on the frontend")
@@ -60,7 +60,7 @@ func Execute() {
 	if err != nil {
 		panic(fmt.Errorf("cannot connect to web3 provider: %w", err))
 	}
-	config := server.NewConfig(*netnameFlag, *symbolFlag, *httpPortFlag, *intervalFlag, *payoutFlag, *proxyCntFlag, *hcaptchaSiteKeyFlag, *hcaptchaSecretFlag)
+	config := server.NewConfig(*netnameFlag, *symbolFlag, *httpPortFlag, *intervalFlag, *proxyCntFlag, *payoutFlag, *hcaptchaSiteKeyFlag, *hcaptchaSecretFlag)
 	go server.NewServer(txBuilder, config).Run()
 
 	c := make(chan os.Signal, 1)

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/ethereum/go-ethereum v1.10.26
 	github.com/jellydator/ttlcache/v2 v2.11.1
 	github.com/kataras/hcaptcha v0.0.2
+	github.com/shopspring/decimal v1.4.0
 	github.com/sirupsen/logrus v1.9.3
 	github.com/urfave/negroni v1.0.0
 )

go.sum

@@ -339,6 +339,8 @@ github.com/segmentio/kafka-go v0.2.0/go.mod h1:X6itGqS9L4jDletMsxZ7Dz+JFWxM6JHfP
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible h1:Bn1aCHHRnjv4Bl16T8rcaFjYSrGrIZvpiGO6P3Q4GpU=
 github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=
+github.com/shopspring/decimal v1.4.0 h1:bxl37RwXBklmTi0C79JfXCEBD1cqqHt0bbgBAGFp81k=
+github.com/shopspring/decimal v1.4.0/go.mod h1:gawqmDU56v4yIKSwfBSFip1HdCCXN8/+DMd9qYNcwME=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=

internal/chain/transaction.go

@@ -87,7 +87,6 @@ func (b *TxBuild) Transfer(ctx context.Context, to string, value *big.Int) (comm
 	}
 
 	if err = b.client.SendTransaction(ctx, signedTx); err != nil {
-		log.Error("failed to send tx", "tx hash", signedTx.Hash().String(), "err", err)
 		if strings.Contains(strings.ToLower(err.Error()), "nonce") {
 			b.refreshNonce(context.Background())
 		}
@@ -145,7 +144,10 @@ func (b *TxBuild) getAndIncrementNonce() uint64 {
 func (b *TxBuild) refreshNonce(ctx context.Context) {
 	nonce, err := b.client.PendingNonceAt(ctx, b.Sender())
 	if err != nil {
-		log.Error("failed to refresh nonce", "address", b.Sender(), "err", err)
+		log.WithFields(log.Fields{
+			"address": b.Sender(),
+			"error":   err,
+		}).Error("failed to refresh account nonce")
 		return
 	}
 

internal/chain/util.go

@@ -4,11 +4,14 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/shopspring/decimal"
 )
 
-func EtherToWei(amount int64) *big.Int {
-	ether := new(big.Int).Exp(big.NewInt(10), big.NewInt(18), nil)
-	return new(big.Int).Mul(big.NewInt(amount), ether)
+func EtherToWei(amount float64) *big.Int {
+	oneEther := decimal.NewFromFloat(1e18)
+	result := decimal.NewFromFloat(amount).Mul(oneEther)
+	wei, _ := new(big.Int).SetString(result.String(), 10)
+	return wei
 }
 
 func Has0xPrefix(str string) bool {

internal/chain/util_test.go

@@ -35,9 +35,11 @@ func TestIsValidAddress(t *testing.T) {
 func TestEtherToWei(t *testing.T) {
 	tests := []struct {
 		name   string
-		amount int64
+		amount float64
 		want   *big.Int
 	}{
+		{name: "0.01ether", amount: 0.01, want: new(big.Int).Exp(big.NewInt(10), big.NewInt(16), nil)},
+		{name: "0.1ether", amount: 0.1, want: new(big.Int).Exp(big.NewInt(10), big.NewInt(17), nil)},
 		{name: "1ether", amount: 1, want: new(big.Int).Exp(big.NewInt(10), big.NewInt(18), nil)},
 	}
 	for _, tt := range tests {

internal/server/config.go

@@ -5,13 +5,13 @@ type Config struct {
 	symbol          string
 	httpPort        int
 	interval        int
-	payout          int
+	payout          float64
 	proxyCount      int
 	hcaptchaSiteKey string
 	hcaptchaSecret  string
 }
 
-func NewConfig(network, symbol string, httpPort, interval, payout, proxyCount int, hcaptchaSiteKey, hcaptchaSecret string) *Config {
+func NewConfig(network, symbol string, httpPort, interval, proxyCount int, payout float64, hcaptchaSiteKey, hcaptchaSecret string) *Config {
 	return &Config{
 		network:         network,
 		symbol:          symbol,

internal/server/server.go

@@ -55,7 +55,7 @@ func (s *Server) handleClaim() http.HandlerFunc {
 		address, _ := readAddress(r)
 		ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
 		defer cancel()
-		txHash, err := s.Transfer(ctx, address, chain.EtherToWei(int64(s.cfg.payout)))
+		txHash, err := s.Transfer(ctx, address, chain.EtherToWei(s.cfg.payout))
 		if err != nil {
 			log.WithError(err).Error("Failed to send transaction")
 			renderJSON(w, claimResponse{Message: err.Error()}, http.StatusInternalServerError)
@@ -81,7 +81,7 @@ func (s *Server) handleInfo() http.HandlerFunc {
 			Account:         s.Sender().String(),
 			Network:         s.cfg.network,
 			Symbol:          s.cfg.symbol,
-			Payout:          strconv.Itoa(s.cfg.payout),
+			Payout:          strconv.FormatFloat(s.cfg.payout, 'f', -1, 64),
 			HcaptchaSiteKey: s.cfg.hcaptchaSiteKey,
 		}, http.StatusOK)
 	}