tornado-relayer/src/treeWatcher.js
2020-10-02 13:26:05 +03:00

98 lines
3.2 KiB
JavaScript

const MerkleTree = require('fixed-merkle-tree')
const { redisUrl, rpcUrl, minerMerkleTreeHeight, minerAddress } = require('../config')
const { poseidonHash2 } = require('./utils')
const { toBN } = require('web3-utils')
const Redis = require('ioredis')
const redis = new Redis(redisUrl)
const Web3 = require('web3')
const web3 = new Web3(rpcUrl)
const contract = new web3.eth.Contract(require('../abis/mining.abi.json'), minerAddress)
let tree, eventSubscription, blockSubscription
// todo handle the situation when we have two rewards in one block
async function fetchEvents(from = 0, to = 'latest') {
const events = await contract.getPastEvents('NewAccount', {
fromBlock: from,
toBlock: to,
})
return events
.sort((a, b) => a.returnValues.index - b.returnValues.index)
.map(e => toBN(e.returnValues.commitment))
}
async function processNewEvent(err, event) {
if (err) {
throw new Error(`Event handler error: ${err}`)
// console.error(err)
// return
}
console.log('New account event', event.returnValues)
const { commitment, index } = event.returnValues
if (tree.elements().length === Number(index)) {
tree.insert(toBN(commitment))
await updateRedis()
} else if (tree.elements().length === Number(index) + 1) {
console.log('Replacing element', index)
tree.update(index, toBN(commitment))
await updateRedis()
} else {
console.log(`Invalid element index ${index}, rebuilding tree`)
await rebuild()
}
}
async function processNewBlock(err) {
if (err) {
throw new Error(`Event handler error: ${err}`)
// console.error(err)
// return
}
// what if updateRedis takes more than 15 sec?
await updateRedis()
}
async function updateRedis() {
const rootOnContract = await contract.methods.getLastAccountRoot().call()
if (!tree.root().eq(toBN(rootOnContract))) {
console.log(`Invalid tree root: ${tree.root()} != ${toBN(rootOnContract)}, rebuilding tree`)
await rebuild()
return
}
const rootInRedis = await redis.get('tree:root')
if (!rootInRedis || !tree.root().eq(toBN(rootInRedis))) {
const serializedTree = JSON.stringify(tree.serialize())
await redis.set('tree:elements', serializedTree)
await redis.set('tree:root', tree.root().toString())
await redis.publish('treeUpdate', tree.root().toString())
console.log('Updated tree in redis, new root:', tree.root().toString())
} else {
console.log('Tree in redis is up to date, skipping update')
}
}
async function rebuild() {
await eventSubscription.unsubscribe()
await blockSubscription.unsubscribe()
setTimeout(init, 3000)
}
async function init() {
console.log('Initializing')
const block = await web3.eth.getBlockNumber()
const events = await fetchEvents(0, block)
tree = new MerkleTree(minerMerkleTreeHeight, events, { hashFunction: poseidonHash2 })
console.log(`Rebuilt tree with ${events.length} elements, root: ${tree.root()}`)
eventSubscription = contract.events.NewAccount({ fromBlock: block + 1 }, processNewEvent)
blockSubscription = web3.eth.subscribe('newBlockHeaders', processNewBlock)
await updateRedis()
}
init()
process.on('unhandledRejection', error => {
console.error('Unhandled promise rejection', error)
process.exit(1)
})