multi: rename mock oracle flags, add secondary option

To make the use of the mock oracle price flag way more clear, we first
rename it to correctly represent its usage.
We then also make sure a minimum value is set, otherwise one asset unit
would just cost too much and cause issues when trying to send them over
the network.
To make it easier to express what one unit should cost, we also add a
second price flag that can specify the number of satoshis per asset
unit, which will make it easier for users that want to represent
something that doesn't have an official exchange rate.

Author: guggero

itest/tapd_harness.go

@@ -222,8 +222,9 @@ func newTapdHarness(t *testing.T, ht *harnessTest, cfg tapdConfig,
 	// Set the experimental config for the RFQ service.
 	tapCfg.Experimental = &tapcfg.ExperimentalConfig{
 		Rfq: rfq.CliConfig{
-			PriceOracleAddress:   rfq.MockPriceOracleServiceAddress,
-			MockOracleCentPerSat: 5_820_600,
+			//nolint:lll
+			PriceOracleAddress:     rfq.MockPriceOracleServiceAddress,
+			MockOracleAssetsPerBTC: 5_820_600,
 		},
 	}
 

rfq/cli.go

@@ -7,6 +7,12 @@ import (
 const (
 	MockPriceOracleServiceAddress = "use_mock_price_oracle_service_" +
 		"promise_to_not_use_on_mainnet"
+
+	// MinAssetsPerBTC is the minimum number of asset units that one BTC
+	// should cost. If the value is lower, then one asset unit would cost
+	// too much to be able to represent small amounts of satoshis. With this
+	// value, one asset unit would still cost 1k sats.
+	MinAssetsPerBTC = 100_000
 )
 
 // CliConfig is a struct that holds tapd cli configuration options for the RFQ
@@ -18,18 +24,21 @@ type CliConfig struct {
 
 	SkipAcceptQuotePriceCheck bool `long:"skipacceptquotepricecheck" description:"Accept any price quote returned by RFQ peer, skipping price validation"`
 
-	MockOracleCentPerSat uint64 `long:"mockoraclecentpersat" description:"Mock price oracle static USD cent per sat rate"`
+	MockOracleAssetsPerBTC uint64 `long:"mockoracleassetsperbtc" description:"Mock price oracle static asset units per BTC rate (for example number of USD cents per BTC if one asset unit represents a USD cent); whole numbers only, use either this or mockoraclesatsperasset depending on required precision"`
+
+	MockOracleSatsPerAsset uint64 `long:"mockoraclesatsperasset" description:"Mock price oracle static satoshis per asset unit rate (for example number of satoshis to pay for one USD cent if one asset unit represents a USD cent); whole numbers only, use either this or mockoracleassetsperbtc depending on required precision"`
 }
 
 // Validate returns an error if the configuration is invalid.
 func (c *CliConfig) Validate() error {
 	// If the user has specified a mock oracle USD per BTC rate but the
 	// price oracle address is not the mock price oracle service address,
 	// then we'll return an error.
-	if c.MockOracleCentPerSat > 0 &&
+	if (c.MockOracleAssetsPerBTC > 0 || c.MockOracleSatsPerAsset > 0) &&
 		c.PriceOracleAddress != MockPriceOracleServiceAddress {
 
-		return fmt.Errorf("mockoraclecentpersat can only be used "+
+		return fmt.Errorf("mockoracleassetsperbtc or "+
+			"mockoraclesatsperasset can only be used "+
 			"with the mock price oracle service, set "+
 			"priceoracleaddress to %s",
 			MockPriceOracleServiceAddress)
@@ -39,12 +48,35 @@ func (c *CliConfig) Validate() error {
 	// has not set the mock oracle USD per BTC rate, then we'll return an
 	// error.
 	if c.PriceOracleAddress == MockPriceOracleServiceAddress &&
-		c.MockOracleCentPerSat == 0 {
+		c.MockOracleAssetsPerBTC == 0 && c.MockOracleSatsPerAsset == 0 {
 
-		return fmt.Errorf("mockoraclecentpersat must be set when " +
+		return fmt.Errorf("mockoracleassetsperbtc or " +
+			"mockoraclesatsperasset must be set when " +
 			"using the mock price oracle service")
 	}
 
+	// Only one of the mock oracle rates can be set.
+	if c.MockOracleAssetsPerBTC > 0 && c.MockOracleSatsPerAsset > 0 {
+		return fmt.Errorf("only one of mockoracleassetsperbtc or " +
+			"mockoraclesatsperasset can be set")
+	}
+
+	// The MockOracleAssetsPerBTC is more precise for tracking the actual
+	// BTC price but less optimal for just specifying a dummy or test rate
+	// for an asset that isn't BTC. The smaller the value, the more one
+	// asset costs. If we allowed a value of 1, then one asset unit would
+	// cost 1 BTC, which cannot really easily be transported over the
+	// network. So we require a value of at least 100k, which would still
+	// mean that one asset unit costs 1k sats.
+	if c.MockOracleAssetsPerBTC > 0 &&
+		c.MockOracleAssetsPerBTC < MinAssetsPerBTC {
+
+		return fmt.Errorf("mockoracleassetsperbtc must be at least "+
+			"%d asset units per BTC, otherwise one asset "+
+			"unit would cost more than 1k sats per unit",
+			MinAssetsPerBTC)
+	}
+
 	// Ensure that if the price oracle address not the mock price oracle
 	// service address then it must be a valid gRPC address.
 	if c.PriceOracleAddress != "" &&

rfq/oracle.go

@@ -383,6 +383,17 @@ func NewMockPriceOracle(expiryDelay, assetsPerBTC uint64) *MockPriceOracle {
 	}
 }
 
+// NewMockPriceOracleSatPerAsset creates a new mock price oracle with a
+// specified satoshis per asset rate.
+func NewMockPriceOracleSatPerAsset(expiryDelay uint64,
+	satPerAsset btcutil.Amount) *MockPriceOracle {
+
+	return &MockPriceOracle{
+		expiryDelay:  expiryDelay,
+		mSatPerAsset: lnwire.NewMSatFromSatoshis(satPerAsset),
+	}
+}
+
 // QueryAskPrice returns the ask price for the given asset amount.
 func (m *MockPriceOracle) QueryAskPrice(_ context.Context,
 	_ *asset.ID, _ *btcec.PublicKey, _ uint64,

sample-tapd.conf

@@ -320,5 +320,13 @@
 ; Accept any price quote returned by RFQ peer, skipping price validation
 ; experimental.rfq.skipacceptquotepricecheck=false
 
-; Mock price oracle static USD cent per sat rate
-; experimental.rfq.mockoraclecentpersat=
+; Mock price oracle static asset units per BTC rate (for example number of USD
+; cents per BTC if one asset unit represents a USD cent); whole numbers only,
+; use either this or mockoraclesatsperasset depending on required precision
+; experimental.rfq.mockoracleassetsperbtc=
+
+; Mock price oracle static satoshis per asset unit rate (for example number of
+; satoshis to pay for one USD cent if one asset unit represents a USD cent);
+; whole numbers only, use either this or mockoracleassetsperbtc depending on
+; required precision
+; experimental.rfq.mockoraclesatsperasset=

tapcfg/server.go

@@ -7,6 +7,7 @@ import (
 	"encoding/binary"
 	"fmt"
 
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btclog"
 	"github.com/lightninglabs/lndclient"
 	tap "github.com/lightninglabs/taproot-assets"
@@ -330,11 +331,22 @@ func genServerConfig(cfg *Config, cfgLogger btclog.Logger,
 	// real price oracle service.
 	var priceOracle rfq.PriceOracle
 
-	switch cfg.Experimental.Rfq.PriceOracleAddress {
+	rfqCfg := cfg.Experimental.Rfq
+	switch rfqCfg.PriceOracleAddress {
 	case rfq.MockPriceOracleServiceAddress:
-		priceOracle = rfq.NewMockPriceOracle(
-			3600, cfg.Experimental.Rfq.MockOracleCentPerSat,
-		)
+		switch {
+		case rfqCfg.MockOracleAssetsPerBTC > 0:
+			priceOracle = rfq.NewMockPriceOracle(
+				3600, rfqCfg.MockOracleAssetsPerBTC,
+			)
+
+		case rfqCfg.MockOracleSatsPerAsset > 0:
+			priceOracle = rfq.NewMockPriceOracleSatPerAsset(
+				3600, btcutil.Amount(
+					rfqCfg.MockOracleSatsPerAsset,
+				),
+			)
+		}
 
 	case "":
 		// Leave the price oracle as nil, which will cause the RFQ
@@ -343,7 +355,7 @@ func genServerConfig(cfg *Config, cfgLogger btclog.Logger,
 
 	default:
 		priceOracle, err = rfq.NewRpcPriceOracle(
-			cfg.Experimental.Rfq.PriceOracleAddress, false,
+			rfqCfg.PriceOracleAddress, false,
 		)
 		if err != nil {
 			return nil, fmt.Errorf("unable to create price "+
@@ -360,7 +372,7 @@ func genServerConfig(cfg *Config, cfgLogger btclog.Logger,
 			ChannelLister:   walletAnchor,
 			AliasManager:    lndRouterClient,
 			// nolint: lll
-			SkipAcceptQuotePriceCheck: cfg.Experimental.Rfq.SkipAcceptQuotePriceCheck,
+			SkipAcceptQuotePriceCheck: rfqCfg.SkipAcceptQuotePriceCheck,
 			ErrChan:                   mainErrChan,
 		},
 	)