eth: discard gas prices below minGasPrice

CHANGELOG_PENDING.md

@@ -25,4 +25,6 @@
 
 #### Orchestrator
 
+- \#1860 Discard low gas prices to prevent insufficient ticket faceValue errors (@kyriediculous)
+
 #### Transcoder

cmd/livepeer/livepeer.go

@@ -22,6 +22,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/livepeer/go-livepeer/build"
 	"github.com/livepeer/go-livepeer/pm"
@@ -192,6 +193,7 @@ func main() {
 
 	type NetworkConfig struct {
 		ethController string
+		minGasPrice   *big.Int
 	}
 
 	ctx := context.Background()
@@ -202,6 +204,7 @@ func main() {
 		},
 		"mainnet": {
 			ethController: "0xf96d54e490317c557a967abfa5d6e33006be69b3",
+			minGasPrice:   big.NewInt(int64(params.GWei)),
 		},
 	}
 
@@ -224,9 +227,11 @@ func main() {
 	}
 
 	// Setting config options based on specified network
+	var minGasPrice = big.NewInt(0)
 	if netw, ok := configOptions[*network]; ok {
 		if *ethController == "" {
 			*ethController = netw.ethController
+			minGasPrice = netw.minGasPrice
 		}
 		glog.Infof("***Livepeer is running on the %v network: %v***", *network, *ethController)
 	} else {
@@ -542,7 +547,7 @@ func main() {
 
 			sigVerifier := &pm.DefaultSigVerifier{}
 			validator := pm.NewValidator(sigVerifier, timeWatcher)
-			gpm := eth.NewGasPriceMonitor(backend, blockPollingTime)
+			gpm := eth.NewGasPriceMonitor(backend, blockPollingTime, minGasPrice)
 			// Start gas price monitor
 			_, err := gpm.Start(ctx)
 			if err != nil {

eth/gaspricemonitor.go

@@ -32,18 +32,25 @@ type GasPriceMonitor struct {
 	gasPriceMu sync.RWMutex
 	// gasPrice is the current gas price to be returned to users
 	gasPrice *big.Int
+	// minGasPrice is the minimum gas price below which polled values will be discarded
+	minGasPrice *big.Int
 
 	// update is a channel used to send notifications to a listener
 	// when the gas price is updated
 	update chan struct{}
 }
 
 // NewGasPriceMonitor returns a GasPriceMonitor
-func NewGasPriceMonitor(gpo GasPriceOracle, pollingInterval time.Duration) *GasPriceMonitor {
+func NewGasPriceMonitor(gpo GasPriceOracle, pollingInterval time.Duration, minGasPrice *big.Int) *GasPriceMonitor {
+	minGasP := big.NewInt(0)
+	if minGasPrice != nil {
+		minGasP = minGasPrice
+	}
 	return &GasPriceMonitor{
 		gpo:             gpo,
 		pollingInterval: pollingInterval,
 		gasPrice:        big.NewInt(0),
+		minGasPrice:     minGasP,
 	}
 }
 
@@ -124,10 +131,12 @@ func (gpm *GasPriceMonitor) fetchAndUpdateGasPrice(ctx context.Context) error {
 		return err
 	}
 
-	gpm.updateGasPrice(gasPrice)
+	if gasPrice.Cmp(gpm.minGasPrice) >= 0 {
+		gpm.updateGasPrice(gasPrice)
 
-	if monitor.Enabled {
-		monitor.SuggestedGasPrice(gasPrice)
+		if monitor.Enabled {
+			monitor.SuggestedGasPrice(gasPrice)
+		}
 	}
 
 	return nil

eth/gaspricemonitor_test.go

@@ -58,7 +58,7 @@ func TestStart(t *testing.T) {
 	gasPrice := big.NewInt(777)
 	gpo := newStubGasPriceOracle(gasPrice)
 
-	gpm := NewGasPriceMonitor(gpo, 1*time.Hour)
+	gpm := NewGasPriceMonitor(gpo, 1*time.Hour, big.NewInt(0))
 
 	assert := assert.New(t)
 
@@ -93,10 +93,11 @@ func TestStart_Polling(t *testing.T) {
 	gasPrice1 := big.NewInt(777)
 	gasPrice2 := big.NewInt(555)
 	gasPrice3 := big.NewInt(888)
+	gasPrice4 := big.NewInt(1)
 	gpo := newStubGasPriceOracle(gasPrice1)
 
 	pollingInterval := 1 * time.Millisecond
-	gpm := NewGasPriceMonitor(gpo, pollingInterval)
+	gpm := NewGasPriceMonitor(gpo, pollingInterval, big.NewInt(10))
 
 	assert := assert.New(t)
 
@@ -131,14 +132,23 @@ func TestStart_Polling(t *testing.T) {
 	// There should be more queries now
 	assert.Greater(gpo.Queries(), queries)
 	assert.Equal(gasPrice3, gpm.GasPrice())
+
+	queries = gpo.Queries()
+
+	go func() {
+		gpo.SetGasPrice(gasPrice4)
+	}()
+	time.Sleep(100 * time.Millisecond)
+	assert.Greater(gpo.Queries(), queries)
+	assert.Equal(gasPrice3, gpm.GasPrice())
 }
 
 func TestStart_Polling_ContextCancel(t *testing.T) {
 	gasPrice1 := big.NewInt(777)
 	gpo := newStubGasPriceOracle(gasPrice1)
 
 	pollingInterval := 1 * time.Second
-	gpm := NewGasPriceMonitor(gpo, pollingInterval)
+	gpm := NewGasPriceMonitor(gpo, pollingInterval, big.NewInt(0))
 
 	ctx, cancel := context.WithCancel(context.Background())
 	update, err := gpm.Start(ctx)
@@ -161,7 +171,7 @@ func TestStop(t *testing.T) {
 	gpo := newStubGasPriceOracle(gasPrice)
 	gpo.SetGasPrice(gasPrice)
 
-	gpm := NewGasPriceMonitor(gpo, 1*time.Hour)
+	gpm := NewGasPriceMonitor(gpo, 1*time.Hour, big.NewInt(0))
 
 	assert := assert.New(t)