add health watcher

package.json

@@ -1,18 +1,19 @@
 {
   "name": "relay",
-  "version": "4.0.1",
+  "version": "4.0.2",
   "description": "Relayer for Tornado.cash privacy solution. https://tornado.cash",
   "scripts": {
     "server": "node src/server.js",
     "worker": "node src/worker",
     "treeWatcher": "node src/treeWatcher",
     "priceWatcher": "node src/priceWatcher",
+    "healthWatcher": "node src/healthWatcher",
     "eslint": "eslint --ext .js --ignore-path .gitignore .",
     "prettier:check": "npx prettier --check . --config .prettierrc",
     "prettier:fix": "npx prettier --write . --config .prettierrc",
     "lint": "yarn eslint && yarn prettier:check",
     "test": "mocha",
-    "start": "yarn server & yarn priceWatcher & yarn treeWatcher & yarn worker "
+    "start": "yarn server & yarn priceWatcher & yarn treeWatcher & yarn worker & yarn healthWatcher"
   },
   "author": "tornado.cash",
   "license": "MIT",

src/config.js

@@ -24,4 +24,5 @@ module.exports = {
     [jobType.MINING_REWARD]: 800000,
     [jobType.MINING_WITHDRAW]: 800000,
   },
+  minimumBalance: 1000000000000000000,
 }

src/healthWatcher.js

@@ -0,0 +1,27 @@
+const Web3 = require('web3')
+const Redis = require('ioredis')
+const { toBN, fromWei } = require('web3-utils')
+
+const { setSafeInterval } = require('./utils')
+const { redisUrl, httpRpcUrl, privateKey, minimumBalance } = require('./config')
+
+const web3 = new Web3(httpRpcUrl)
+const redis = new Redis(redisUrl)
+
+async function main() {
+  try {
+    const { address } = web3.eth.accounts.privateKeyToAccount(privateKey)
+    const balance = await web3.eth.getBalance(address)
+
+    if (toBN(balance).lt(toBN(minimumBalance))) {
+      throw new Error(`Not enough balance, less than ${fromWei(minimumBalance.toString())} ETH`)
+    }
+
+    await redis.hset('health', { status: true, error: '' })
+  } catch (e) {
+    console.error('healthWatcher', e.message)
+    await redis.hset('health', { status: false, error: e.message })
+  }
+}
+
+setSafeInterval(main, 30 * 1000)

src/status.js

@@ -6,6 +6,10 @@ const redis = new Redis(redisUrl)
 
 async function status(req, res) {
   const ethPrices = await redis.hgetall('prices')
+  const health = await redis.hgetall('health')
+
+  const { waiting: currentQueue } = await queue.queue.getJobCounts()
+
   res.json({
     rewardAccount,
     instances: instances[`netId${netId}`],
@@ -14,6 +18,8 @@ async function status(req, res) {
     tornadoServiceFee,
     miningServiceFee,
     version,
+    health,
+    currentQueue,
   })
 }