watcher

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true

.env.example

@@ -8,5 +8,14 @@ REDIS_URL=redis://127.0.0.1:6379
 PRIVATE_KEY=
 # 2.5 means 2.5%
 RELAYER_FEE=2.5
-
 APP_PORT=8000
+
+# Resubmitter params:
+# how often the watcher will check the first pending tx (in seconds)
+NONCE_WATCHER_INTERVAL=30
+# how long a tx can be in pending pool (in seconds)
+ALLOWABLE_PENDING_TX_TIMEOUT=180
+# in GWEI
+MAX_GAS_PRICE=100
+# how much to increase the gas price for a stuck tx
+GAS_PRICE_BUMP_PERCENTAGE=20

config.js

@@ -147,5 +147,9 @@ module.exports = {
   defaultGasPrice: 20,
   gasOracleUrls: ['https://ethgasstation.info/json/ethgasAPI.json', 'https://gas-oracle.zoltu.io/'],
   port: process.env.APP_PORT,
-  relayerServiceFee: Number(process.env.RELAYER_FEE)
+  relayerServiceFee: Number(process.env.RELAYER_FEE),
+  maxGasPrice: process.env.MAX_GAS_PRICE,
+  watherInterval: Number(process.env.NONCE_WATCHER_INTERVAL) * 1000,
+  pendingTxTimeout: Number(process.env.ALLOWABLE_PENDING_TX_TIMEOUT) * 1000,
+  gasBumpPercentage: process.env.GAS_PRICE_BUMP_PERCENTAGE
 }

src/Fetcher.js

@@ -63,7 +63,7 @@ class Fetcher {
         if (json.percentile_97) {
           this.gasPrices.fast = parseInt(json.percentile_90) + 1 / delimiter
         }
-        console.log('gas price fetch', this.gasPrices)
+        // console.log('gas price fetch', this.gasPrices)
       } else {
         throw Error('Fetch gasPrice failed')
       }

src/instances.js

@@ -2,7 +2,7 @@ const Fetcher = require('./Fetcher')
 const Sender = require('./Sender')
 const web3 = require('./setupWeb3')
 const fetcher = new Fetcher(web3)
-const sender = new Sender(1, web3)
+const sender = new Sender(web3)
 
 module.exports = {
   fetcher,

src/relayController.js

@@ -120,27 +120,18 @@ withdrawQueue.process(async function(job, done){
       value: numberToHex(refund),
       gas: numberToHex(gas),
       gasPrice: toHex(toWei(gasPrices.fast.toString(), 'gwei')),
+      // you can use this gasPrice to test watcher
+      // gasPrice: numberToHex(100000000),
       to: mixer._address,
       netId: config.netId,
       data,
       nonce
     }
+    tx.date = Date.now()
     await redisClient.set('tx:' + nonce, JSON.stringify(tx) )
     nonce += 1
     await redisClient.set('nonce', nonce)
-    try {
-      const txHash = await sender.sendTx(tx)
-      done(null, {
-        status: 200,
-        msg: { txHash }
-      })
-    } catch (e) {
-      console.error('on transactionHash error', e.message)
-      done(null, {
-        status: 400,
-        msg: { error: 'Internal Relayer Error. Please use a different relayer service' }
-      })
-    }
+    sender.sendTx(tx, done)
   } catch (e) {
     console.error(e, 'estimate gas failed')
     done(null, {

src/sender.js

@@ -1,36 +1,53 @@
 const { redisClient } = require('./redis')
 const config = require('../config')
+const { toBN, toHex, toWei, BN, fromWei } = require('web3-utils')
 
 class Sender {
-  constructor(minedNonce, web3) {
-    this.minedNonce = Number(minedNonce)
+  constructor(web3) {
     this.web3 = web3
+    this.watherInterval = config.watherInterval
+    this.pendingTxTimeout = config.pendingTxTimeout
+    this.gasBumpPercentage = config.gasBumpPercentage
+    this.watcher()
   }
 
-  async main() {
-    const lastNonce = await redisClient.get('nonce')
-    for(let nonce = this.minedNonce; nonce < lastNonce + 1; nonce++) {
-      let tx = await redisClient.get('tx' + nonce)
-      tx = JSON.parse(tx)
-      const isMined = await this.checkTx(tx)
-
-    }
-  }
-
-  async checkTx(tx) {
+  async watcher() {
+    try {
       const networkNonce = await this.web3.eth.getTransactionCount(this.web3.eth.defaultAccount)
-    if ()
+      let tx = await redisClient.get('tx:' + networkNonce)
+      if (tx) {
+        tx = JSON.parse(tx)
+        if (Date.now() - tx.date > this.pendingTxTimeout) {
+          const newGasPrice = toBN(tx.gasPrice).mul(toBN(this.gasBumpPercentage)).div(toBN(100))
+          const maxGasPrice = toBN(toWei(config.maxGasPrice))
+          tx.gasPrice = toHex(BN.min(newGasPrice, maxGasPrice))
+          tx.date = Date.now()
+          await redisClient.set('tx:' + tx.nonce, JSON.stringify(tx) )
+          console.log('resubmitting with gas price', fromWei(tx.gasPrice.toString()))
+          this.sendTx(tx, null, 9999)
+        }
+      }
+    } catch(e) {
+      console.error('watcher error:', e)
+    } finally {
+      setTimeout(() => this.watcher(), this.watherInterval)
+    }
   }
 
-  async sendTx(tx, retryAttempt = 1) {
+  async sendTx(tx, done, retryAttempt = 1) {
     let signedTx = await this.web3.eth.accounts.signTransaction(tx, config.privateKey)
     let result = this.web3.eth.sendSignedTransaction(signedTx.rawTransaction)
-    let txHash
-    result.once('transactionHash', function(_txHash){
-        console.log(`A new successfully sent tx ${_txHash}`)
-        txHash = _txHash
+
+    result.once('transactionHash', function(txHash){
+      console.log(`A new successfully sent tx ${txHash}`)
+      if (done) {
+        done(null, {
+          status: 200,
+          msg: { txHash }
+        })
+      }
     }).on('error', async function(e){
-      console.log('error', e.message)
+      console.log(`Error for tx with nonce ${tx.nonce}\n${e.message}`)
       if(e.message === 'Returned error: Transaction gas price supplied is too low. There is another transaction with same nonce in the queue. Try increasing the gas price or incrementing the nonce.'
       || e.message === 'Returned error: Transaction nonce is too low. Try incrementing the nonce.'
       || e.message === 'Returned error: nonce too low'
@@ -41,13 +58,18 @@ class Sender {
           const newNonce = tx.nonce + 1
           tx.nonce = newNonce
           await redisClient.set('nonce', newNonce)
-          txHash = this.sendTx(tx, retryAttempt)
+          await redisClient.set('tx:' + newNonce, JSON.stringify(tx))
+          this.sendTx(tx, done, retryAttempt)
           return
         }
       }
-      throw new Error(e.message)
+      if (done) {
+        done(null, {
+          status: 400,
+          msg: { error: 'Internal Relayer Error. Please use a different relayer service' }
+        })
+      }
     })
-    return txHash
   }
 }