onchain prices

.env.example

@@ -1,5 +1,7 @@
 NET_ID=42
 RPC_URL=https://kovan.infura.io
+# ORACLE_RPC_URL should always point to mainnet
+ORACLE_RPC_URL=https://mainnet.infura.io
 REDIS_URL=redis://127.0.0.1:6379
 
 # without 0x prefix

abis/PriceOracle.abi.json

@@ -0,0 +1,33 @@
+[
+	{
+		"constant": true,
+		"inputs": [
+			{
+				"internalType": "contract IERC20[]",
+				"name": "fromTokens",
+				"type": "address[]"
+			},
+			{
+				"internalType": "uint256[]",
+				"name": "oneUnitAmounts",
+				"type": "uint256[]"
+			},
+			{
+				"internalType": "uint256[]",
+				"name": "parts",
+				"type": "uint256[]"
+			}
+		],
+		"name": "getPricesInETH",
+		"outputs": [
+			{
+				"internalType": "uint256[]",
+				"name": "prices",
+				"type": "uint256[]"
+			}
+		],
+		"payable": false,
+		"stateMutability": "view",
+		"type": "function"
+	}
+]

config.js

@@ -1,10 +1,12 @@
 require('dotenv').config()
 
 module.exports = {
-  version: '1.0',
+  version: '1.1',
   netId: Number(process.env.NET_ID) || 42,
   redisUrl: process.env.REDIS_URL,
-  rpcUrl: process.env.RPC_URL || 'https://kovan.infura.io/v3/a3f4d001c1fc4a359ea70dd27fd9cb51',
+  rpcUrl: process.env.RPC_URL || 'https://kovan.infura.io/',
+  oracleRpcUrl: process.env.ORACLE_RPC_URL || 'https://mainnet.infura.io/',
+  oracleAddress: '0x5c4c5622670423b8ee5F3A02F505D139fbAfb618',
   privateKey: process.env.PRIVATE_KEY,
   mixers: {
     netId1: {

package.json

@@ -12,7 +12,6 @@
   "license": "MIT",
   "dependencies": {
     "bull": "^3.12.1",
-    "coingecko-api": "^1.0.6",
     "dotenv": "^8.2.0",
     "express": "^4.17.1",
     "ioredis": "^4.14.1",

src/Fetcher.js

@@ -1,37 +1,50 @@
-const CoinGecko = require('coingecko-api') 
 const fetch = require('node-fetch')
-const { toWei } = require('web3-utils')
-const { gasOracleUrls, defaultGasPrice } = require('../config')
-const { getMainnetTokens } = require('./utils')
+const Web3 = require('Web3')
+const { gasOracleUrls, defaultGasPrice, oracleRpcUrl, oracleAddress } = require('../config')
+const { getArgsForOracle } = require('./utils')
 const { redisClient } = require('./redis')
+const priceOracleABI = require('../abis/PriceOracle.abi.json')
 
 class Fetcher {
   constructor(web3) {
     this.web3 = web3
+    this.oracleWeb3 = new Web3(oracleRpcUrl)
+    this.oracle = new this.oracleWeb3.eth.Contract(priceOracleABI, oracleAddress)
     this.ethPrices = {
-      dai: '6700000000000000' // 0.0067
+      dai: '6700000000000000', // 0.0067
+      cdai: '157380000000000',
+      cusdc: '164630000000000',
+      usdc: '7878580000000000',
+      usdt: '7864940000000000'
     }
+    this.tokenAddresses
+    this.oneUintAmount
+    this.parts
+    this.currencyLookup
     this.gasPrices = {
       fast: defaultGasPrice
     }
+
+    const { tokenAddresses, oneUintAmount, parts, currencyLookup } = getArgsForOracle()
+    this.tokenAddresses = tokenAddresses
+    this.oneUintAmount = oneUintAmount
+    this.parts = parts
+    this.currencyLookup = currencyLookup
   }
   async fetchPrices() {
-    const { tokenAddresses, currencyLookup } = getMainnetTokens()
     try {
-      const CoinGeckoClient = new CoinGecko()
-      const price = await CoinGeckoClient.simple.fetchTokenPrice({
-        contract_addresses: tokenAddresses,
-        vs_currencies: 'eth',
-        assetPlatform: 'ethereum'
-      })
-      this.ethPrices = Object.entries(price.data).reduce((acc, token) => {
-        if (token[1].eth) {
-          acc[currencyLookup[token[0]]] = toWei(token[1].eth.toString())
-        }
+      let prices = await this.oracle.methods.getPricesInETH(
+        this.tokenAddresses,
+        this.oneUintAmount,
+        this.parts
+      ).call()
+      this.ethPrices = prices.reduce((acc, price, i) => {
+        acc[this.currencyLookup[this.tokenAddresses[i]]] = price
         return acc
       }, {})
       setTimeout(() => this.fetchPrices(), 1000 * 30)
     } catch(e) {
+      console.error('fetchPrices', e)
       setTimeout(() => this.fetchPrices(), 1000 * 30)
     }
   }

src/utils.js

@@ -138,21 +138,29 @@ function isEnoughFee({ gas, gasPrices, currency, amount, refund, ethPrices, fee
   return { isEnough: true }
 }
 
-function getMainnetTokens() {
+function getArgsForOracle() {
   const tokens = mixers['netId1']
   const tokenAddresses = []
+  const oneUintAmount = []
+  const parts = [] // this is probably should be removed
   const currencyLookup = {}
   Object.entries(tokens).map(([currency, data]) => {
     if (currency !== 'eth') {
       tokenAddresses.push(data.tokenAddress)
-      currencyLookup[data.tokenAddress.toLowerCase()] = currency
+      oneUintAmount.push(
+        toBN('10')
+          .pow(toBN(data.decimals.toString()))
+          .toString()
+      )
+      parts.push('1')
+      currencyLookup[data.tokenAddress] = currency
     }
   })
-  return { tokenAddresses, currencyLookup }
+  return { tokenAddresses, oneUintAmount, parts, currencyLookup }
 }
 
 function getMixers() {
   return mixers[`netId${netId}`]
 }
 
-module.exports = { isValidProof, isValidArgs, sleep, isKnownContract, isEnoughFee, getMixers, getMainnetTokens }
+module.exports = { isValidProof, isValidArgs, sleep, isKnownContract, isEnoughFee, getMixers, getArgsForOracle }

yarn.lock

@@ -477,11 +477,6 @@ cluster-key-slot@^1.1.0:
   resolved "https://registry.yarnpkg.com/cluster-key-slot/-/cluster-key-slot-1.1.0.tgz#30474b2a981fb12172695833052bc0d01336d10d"
   integrity sha512-2Nii8p3RwAPiFwsnZvukotvow2rIHM+yQ6ZcBXGHdniadkYGZYiGmkHJIbZPIV9nfv7m/U1IPMVVcAhoWFeklw==
 
-coingecko-api@^1.0.6:
-  version "1.0.6"
-  resolved "https://registry.yarnpkg.com/coingecko-api/-/coingecko-api-1.0.6.tgz#ecc42eb96fb1cc721e319c3d06244a642394ab34"
-  integrity sha512-6oJ3aB9F4AlsHQQ4F5N9753FGmMQrr12aGJl79KSfdNOFJ7wvFLSqsBoOBzgYJEab3hJ7cCWnmo2dMJs6KsA3A==
-
 color-convert@^1.9.0:
   version "1.9.3"
   resolved "https://registry.yarnpkg.com/color-convert/-/color-convert-1.9.3.tgz#bb71850690e1f136567de629d2d5471deda4c1e8"