Merge pull request #133 from poanetwork/#132-boundaries-oracle-gas-price

Add boundaries to oracle's gas price

src/services/gasPrice.js

@@ -7,7 +7,7 @@ const logger = require('../services/logger').child({
   module: 'gasPrice'
 })
 const { setIntervalAndRun } = require('../utils/utils')
-const { DEFAULT_UPDATE_INTERVAL } = require('../utils/constants')
+const { DEFAULT_UPDATE_INTERVAL, GAS_PRICE_BOUNDARIES } = require('../utils/constants')
 
 const HomeABI = bridgeConfig.homeBridgeAbi
 const ForeignABI = bridgeConfig.foreignBridgeAbi
@@ -31,13 +31,24 @@ const foreignBridge = new web3Foreign.eth.Contract(ForeignABI, FOREIGN_BRIDGE_AD
 
 let cachedGasPrice = null
 
+function gasPriceWithinLimits(gasPrice) {
+  if (gasPrice < GAS_PRICE_BOUNDARIES.MIN) {
+    return GAS_PRICE_BOUNDARIES.MIN
+  } else if (gasPrice > GAS_PRICE_BOUNDARIES.MAX) {
+    return GAS_PRICE_BOUNDARIES.MAX
+  } else {
+    return gasPrice
+  }
+}
+
 async function fetchGasPriceFromOracle(oracleUrl, speedType) {
   const response = await fetch(oracleUrl)
   const json = await response.json()
-  const gasPrice = json[speedType]
-  if (!gasPrice) {
+  const oracleGasPrice = json[speedType]
+  if (!oracleGasPrice) {
     throw new Error(`Response from Oracle didn't include gas price for ${speedType} type.`)
   }
+  const gasPrice = gasPriceWithinLimits(oracleGasPrice)
   return Web3Utils.toWei(gasPrice.toString(), 'gwei')
 }
 
@@ -102,5 +113,6 @@ function getPrice() {
 module.exports = {
   start,
   fetchGasPrice,
-  getPrice
+  getPrice,
+  gasPriceWithinLimits
 }

src/utils/constants.js

@@ -12,5 +12,9 @@ module.exports = {
     GENERAL_ERROR: 1,
     INCOMPATIBILITY: 10,
     MAX_TIME_REACHED: 11
+  },
+  GAS_PRICE_BOUNDARIES: {
+    MIN: 1,
+    MAX: 250
   }
 }

test/gasPrice.test.js

@@ -1,8 +1,8 @@
 const sinon = require('sinon')
 const { expect } = require('chai')
 const proxyquire = require('proxyquire').noPreserveCache()
-const { fetchGasPrice } = require('../src/services/gasPrice')
-const { DEFAULT_UPDATE_INTERVAL } = require('../src/utils/constants')
+const { fetchGasPrice, gasPriceWithinLimits } = require('../src/services/gasPrice')
+const { DEFAULT_UPDATE_INTERVAL, GAS_PRICE_BOUNDARIES } = require('../src/utils/constants')
 
 describe('gasPrice', () => {
   describe('fetchGasPrice', () => {
@@ -138,4 +138,42 @@ describe('gasPrice', () => {
       expect(utils.setIntervalAndRun.args[0][1]).to.equal(DEFAULT_UPDATE_INTERVAL)
     })
   })
+  describe('gasPriceWithinLimits', () => {
+    it('should return gas price if gas price is between boundaries', () => {
+      // given
+      const minGasPrice = 1
+      const middleGasPrice = 10
+      const maxGasPrice = 250
+
+      // when
+      const minGasPriceWithinLimits = gasPriceWithinLimits(minGasPrice)
+      const middleGasPriceWithinLimits = gasPriceWithinLimits(middleGasPrice)
+      const maxGasPriceWithinLimits = gasPriceWithinLimits(maxGasPrice)
+
+      // then
+      expect(minGasPriceWithinLimits).to.equal(minGasPrice)
+      expect(middleGasPriceWithinLimits).to.equal(middleGasPrice)
+      expect(maxGasPriceWithinLimits).to.equal(maxGasPrice)
+    })
+    it('should return min limit if gas price is below min boundary', () => {
+      // Given
+      const initialGasPrice = 0.5
+
+      // When
+      const gasPrice = gasPriceWithinLimits(initialGasPrice)
+
+      // Then
+      expect(gasPrice).to.equal(GAS_PRICE_BOUNDARIES.MIN)
+    })
+    it('should return max limit if gas price is above max boundary', () => {
+      // Given
+      const initialGasPrice = 260
+
+      // When
+      const gasPrice = gasPriceWithinLimits(initialGasPrice)
+
+      // Then
+      expect(gasPrice).to.equal(GAS_PRICE_BOUNDARIES.MAX)
+    })
+  })
 })