tokenbridge/monitor/validators.js

require('dotenv').config()
const Web3 = require('web3')
const fetch = require('node-fetch')
const logger = require('./logger')('validators')
const { getBridgeABIs } = require('./utils/bridgeMode')
const { getValidatorList } = require('./utils/validatorUtils')
const { getBlockNumber } = require('./utils/contract')

const {
  HOME_RPC_URL,
  FOREIGN_RPC_URL,
  HOME_BRIDGE_ADDRESS,
  FOREIGN_BRIDGE_ADDRESS,
  GAS_PRICE_SPEED_TYPE,
  GAS_LIMIT,
  GAS_PRICE_FALLBACK
} = process.env
const HOME_DEPLOYMENT_BLOCK = Number(process.env.HOME_DEPLOYMENT_BLOCK) || 0
const FOREIGN_DEPLOYMENT_BLOCK = Number(process.env.FOREIGN_DEPLOYMENT_BLOCK) || 0

const Web3Utils = Web3.utils

const homeProvider = new Web3.providers.HttpProvider(HOME_RPC_URL)
const web3Home = new Web3(homeProvider)

const foreignProvider = new Web3.providers.HttpProvider(FOREIGN_RPC_URL)
const web3Foreign = new Web3(foreignProvider)

const BRIDGE_VALIDATORS_ABI = require('../contracts/build/contracts/BridgeValidators').abi

const asyncForEach = async (array, callback) => {
  for (let index = 0; index < array.length; index++) {
    await callback(array[index], index, array)
  }
}

async function getGasPrices(type) {
  try {
    const response = await fetch('https://gasprice.poa.network/')
    const json = await response.json()
    logger.log('Fetched gasprice: ' + json[type])
    return json[type]
  } catch (e) {
    logger.error('Gas Price API is not available', e)
    return GAS_PRICE_FALLBACK
  }
}

async function main(bridgeMode) {
  const { HOME_ABI, FOREIGN_ABI } = getBridgeABIs(bridgeMode)
  const homeBridge = new web3Home.eth.Contract(HOME_ABI, HOME_BRIDGE_ADDRESS)
  const foreignBridge = new web3Foreign.eth.Contract(FOREIGN_ABI, FOREIGN_BRIDGE_ADDRESS)
  const homeValidatorsAddress = await homeBridge.methods.validatorContract().call()
  const homeBridgeValidators = new web3Home.eth.Contract(
    BRIDGE_VALIDATORS_ABI,
    homeValidatorsAddress
  )

  logger.debug('getting last block numbers')
  const [homeBlockNumber, foreignBlockNumber] = await getBlockNumber(web3Home, web3Foreign)

  logger.debug('calling foreignBridge.methods.validatorContract().call()')
  const foreignValidatorsAddress = await foreignBridge.methods.validatorContract().call()
  const foreignBridgeValidators = new web3Foreign.eth.Contract(
    BRIDGE_VALIDATORS_ABI,
    foreignValidatorsAddress
  )

  logger.debug('calling foreignBridgeValidators getValidatorList()')
  const foreignValidators = await getValidatorList(
    foreignValidatorsAddress,
    web3Foreign.eth,
    FOREIGN_DEPLOYMENT_BLOCK,
    foreignBlockNumber
  )

  logger.debug('calling homeBridgeValidators getValidatorList()')
  const homeValidators = await getValidatorList(
    homeValidatorsAddress,
    web3Home.eth,
    HOME_DEPLOYMENT_BLOCK,
    homeBlockNumber
  )

  const homeBalances = {}
  logger.debug('calling asyncForEach homeValidators homeBalances')
  await asyncForEach(homeValidators, async v => {
    homeBalances[v] = Web3Utils.fromWei(await web3Home.eth.getBalance(v))
  })
  const foreignVBalances = {}
  const homeVBalances = {}
  logger.debug('calling getGasPrices')
  const gasPriceInGwei = await getGasPrices(GAS_PRICE_SPEED_TYPE)
  const gasPrice = new Web3Utils.BN(Web3Utils.toWei(gasPriceInGwei.toString(10), 'gwei'))
  const txCost = gasPrice.mul(new Web3Utils.BN(GAS_LIMIT))
  let validatorsMatch = true
  logger.debug('calling asyncForEach foreignValidators foreignVBalances')
  await asyncForEach(foreignValidators, async v => {
    const balance = await web3Foreign.eth.getBalance(v)
    const leftTx = new Web3Utils.BN(balance).div(txCost).toString(10)
    foreignVBalances[v] = {
      balance: Web3Utils.fromWei(balance),
      leftTx: Number(leftTx),
      gasPrice: gasPriceInGwei
    }
    if (!homeValidators.includes(v)) {
      validatorsMatch = false
      foreignVBalances[v].onlyOnForeign = true
    }
  })
  logger.debug('calling asyncForEach homeValidators homeVBalances')
  await asyncForEach(homeValidators, async v => {
    const gasPrice = new Web3Utils.BN(1)
    const txCost = gasPrice.mul(new Web3Utils.BN(GAS_LIMIT))
    const balance = await web3Home.eth.getBalance(v)
    const leftTx = new Web3Utils.BN(balance).div(txCost).toString(10)
    homeVBalances[v] = {
      balance: Web3Utils.fromWei(balance),
      leftTx: Number(leftTx),
      gasPrice: Number(gasPrice.toString(10))
    }
    if (!foreignValidators.includes(v)) {
      validatorsMatch = false
      homeVBalances[v].onlyOnHome = true
    }
  })
  logger.debug('calling homeBridgeValidators.methods.requiredSignatures().call()')
  const reqSigHome = await homeBridgeValidators.methods.requiredSignatures().call()
  logger.debug('calling foreignBridgeValidators.methods.requiredSignatures().call()')
  const reqSigForeign = await foreignBridgeValidators.methods.requiredSignatures().call()
  logger.debug('Done')
  return {
    home: {
      validators: {
        ...homeVBalances
      },
      requiredSignatures: Number(reqSigHome)
    },
    foreign: {
      validators: {
        ...foreignVBalances
      },
      requiredSignatures: Number(reqSigForeign)
    },
    requiredSignaturesMatch: reqSigHome === reqSigForeign,
    validatorsMatch,
    lastChecked: Math.floor(Date.now() / 1000)
  }
}

module.exports = main