Improve contract fetching

This merge contains the following set of changes:
  * [Oracle, Improvement] Periodic check for RPC sync state (#656)

CONFIGURATION.md

@@ -56,9 +56,11 @@ ORACLE_JSONRPC_ERROR_CODES | Override default JSON rpc error codes that can trig
 ORACLE_HOME_EVENTS_REPROCESSING | If set to `true`, home events happened in the past will be refetched and processed once again, to ensure that nothing was missed on the first pass. | `bool`
 ORACLE_HOME_EVENTS_REPROCESSING_BATCH_SIZE | Batch size for one `eth_getLogs` request when reprocessing old logs in the home chain. Defaults to `1000` | `integer`
 ORACLE_HOME_EVENTS_REPROCESSING_BLOCK_DELAY | Block confirmations number, after which old logs are being reprocessed in the home chain. Defaults to `500` | `integer`
+ORACLE_HOME_RPC_SYNC_STATE_CHECK_INTERVAL | Interval for checking JSON RPC sync state, by requesting the latest block number. Oracle will switch to the fallback JSON RPC in case sync process is stuck | `integer`
 ORACLE_FOREIGN_EVENTS_REPROCESSING  | If set to `true`, foreign events happened in the past will be refetched and processed once again, to ensure that nothing was missed on the first pass. | `bool`
 ORACLE_FOREIGN_EVENTS_REPROCESSING_BATCH_SIZE | Batch size for one `eth_getLogs` request when reprocessing old logs in the foreign chain. Defaults to `500` | `integer`
 ORACLE_FOREIGN_EVENTS_REPROCESSING_BLOCK_DELAY | Block confirmations number, after which old logs are being reprocessed in the foreign chain. Defaults to `250` | `integer`
+ORACLE_FOREIGN_RPC_SYNC_STATE_CHECK_INTERVAL | Interval for checking JSON RPC sync state, by requesting the latest block number. Oracle will switch to the fallback JSON RPC in case sync process is stuck | `integer`
 
 
 ## Monitor configuration

README.md

@@ -19,7 +19,7 @@ Sub-repositories maintained within this monorepo are listed below.
 
 | Sub-repository | Description |
 | --- | --- |
-| [Oracle](oracle/README.md) | Oracle responsible for listening to bridge related events and authorizing asset transfers. |
+| [Oracle](oracle/README.md) | Responsible for listening to bridge related events and authorizing asset transfers. |
 | [Monitor](monitor/README.md) | Tool for checking balances and unprocessed events in bridged networks. |
 | [Deployment](deployment/README.md) | Ansible playbooks for deploying cross-chain bridges. |
 | [Oracle-E2E](oracle-e2e/README.md) | End to end tests for the Oracle |

alm/src/utils/contract.ts

@@ -22,6 +22,16 @@ export const getRequiredBlockConfirmations = async (
   web3: Web3 | null = null,
   api: string = ''
 ) => {
+  let blockConfirmations
+
+  try {
+    blockConfirmations = await contract.methods.requiredBlockConfirmations().call()
+  } catch {}
+
+  if (blockConfirmations) {
+    return parseInt(blockConfirmations)
+  }
+
   const eventsFromSnapshot = snapshotProvider.requiredBlockConfirmationEvents(blockNumber)
   const snapshotBlockNumber = snapshotProvider.snapshotBlockNumber()
 
@@ -35,16 +45,10 @@ export const getRequiredBlockConfirmations = async (
 
   const events = [...eventsFromSnapshot, ...contractEvents]
 
-  let blockConfirmations
-  if (events.length > 0) {
-    // Use the value from last event before the transaction
-    const event = events[events.length - 1]
-    blockConfirmations = event.returnValues.requiredBlockConfirmations
-  } else {
-    // This is a special case where RequiredBlockConfirmationChanged was not emitted during initialization in early versions of AMB
-    // of Sokol - Kovan. In this case the current value is used.
-    blockConfirmations = await contract.methods.requiredBlockConfirmations().call()
-  }
+  // Use the value from last event before the transaction
+  const event = events[events.length - 1]
+  blockConfirmations = event.returnValues.requiredBlockConfirmations
+
   return parseInt(blockConfirmations)
 }
 
@@ -57,6 +61,16 @@ export const getRequiredSignatures = async (
   web3: Web3 | null = null,
   api: string = ''
 ) => {
+  let requiredSignatures
+
+  try {
+    requiredSignatures = await contract.methods.requiredSignatures().call()
+  } catch {}
+
+  if (requiredSignatures) {
+    return parseInt(requiredSignatures)
+  }
+
   if (blockNumber === 'latest') {
     return contract.methods.requiredSignatures().call()
   }
@@ -76,7 +90,7 @@ export const getRequiredSignatures = async (
 
   // Use the value form last event before the transaction
   const event = events[events.length - 1]
-  const { requiredSignatures } = event.returnValues
+  ;({ requiredSignatures } = event.returnValues)
   return parseInt(requiredSignatures)
 }
 
@@ -87,9 +101,13 @@ export const getValidatorList = async (
   web3: Web3 | null = null,
   api: string = ''
 ) => {
-  if (blockNumber === 'latest') {
-    return contract.methods.validatorList().call()
-  }
+  try {
+    const currentList = await contract.methods.validatorList().call()
+
+    if (currentList) {
+      return currentList
+    }
+  } catch {}
 
   const addedEventsFromSnapshot = snapshotProvider.validatorAddedEvents(blockNumber)
   const removedEventsFromSnapshot = snapshotProvider.validatorRemovedEvents(blockNumber)

oracle/README.md

@@ -1,10 +1,10 @@
 # POA TokenBridge / Oracle
-Oracle responsible for listening to bridge related events and authorizing asset transfers.
+An oracle responsible for listening to bridge related events and authorizing asset transfers.
 
 ## Overview
 Please refer to the [POA TokenBridge](../README.md) overview first of all.
 
-The Oracle is deployed on specified validator nodes (only nodes whose private keys correspond to addresses specified in the smart contracts) in the network. It connects to two chains via a Remote Procedure Call (RPC) and is responsible for:
+The oracle is deployed on specified validator nodes (only nodes whose private keys correspond to addresses specified in the smart contracts) in the network. It connects to two chains via a Remote Procedure Call (RPC) and is responsible for:
 - listening to events related to bridge contracts
 - sending transactions to authorize asset transfers
 
@@ -69,7 +69,7 @@ For more information on the Redis/RabbitMQ requirements, see [#90](/../../issues
    }
    ```
 
-## Install and configure the Oracle
+## Install and configure the oracle
 
 1. [Initialize](../README.md#initializing-the-monorepository) the monorepository.
 

oracle/config/base.config.js

@@ -7,7 +7,15 @@ const {
   HOME_AMB_ABI,
   FOREIGN_AMB_ABI
 } = require('../../commons')
-const { web3Home, web3Foreign } = require('../src/services/web3')
+const {
+  web3Home,
+  web3Foreign,
+  web3HomeRedundant,
+  web3HomeFallback,
+  web3ForeignRedundant,
+  web3ForeignFallback,
+  web3ForeignArchive
+} = require('../src/services/web3')
 const { add0xPrefix, privateKeyToAddress } = require('../src/utils/utils')
 const { EXIT_CODES } = require('../src/utils/constants')
 
@@ -27,9 +35,11 @@ const {
   ORACLE_HOME_EVENTS_REPROCESSING,
   ORACLE_HOME_EVENTS_REPROCESSING_BATCH_SIZE,
   ORACLE_HOME_EVENTS_REPROCESSING_BLOCK_DELAY,
+  ORACLE_HOME_RPC_SYNC_STATE_CHECK_INTERVAL,
   ORACLE_FOREIGN_EVENTS_REPROCESSING,
   ORACLE_FOREIGN_EVENTS_REPROCESSING_BATCH_SIZE,
-  ORACLE_FOREIGN_EVENTS_REPROCESSING_BLOCK_DELAY
+  ORACLE_FOREIGN_EVENTS_REPROCESSING_BLOCK_DELAY,
+  ORACLE_FOREIGN_RPC_SYNC_STATE_CHECK_INTERVAL
 } = process.env
 
 let homeAbi
@@ -63,9 +73,12 @@ const homeConfig = {
   bridgeAddress: COMMON_HOME_BRIDGE_ADDRESS,
   bridgeABI: homeAbi,
   pollingInterval: parseInt(ORACLE_HOME_RPC_POLLING_INTERVAL, 10),
+  syncCheckInterval: parseInt(ORACLE_HOME_RPC_SYNC_STATE_CHECK_INTERVAL, 10) || 60000,
   startBlock: parseInt(ORACLE_HOME_START_BLOCK, 10) || 0,
   blockPollingLimit: parseInt(ORACLE_HOME_RPC_BLOCK_POLLING_LIMIT, 10),
   web3: web3Home,
+  web3Redundant: web3HomeRedundant,
+  web3Fallback: web3HomeFallback,
   bridgeContract: homeContract,
   eventContract: homeContract,
   reprocessingOptions: {
@@ -81,9 +94,13 @@ const foreignConfig = {
   bridgeAddress: COMMON_FOREIGN_BRIDGE_ADDRESS,
   bridgeABI: foreignAbi,
   pollingInterval: parseInt(ORACLE_FOREIGN_RPC_POLLING_INTERVAL, 10),
+  syncCheckInterval: parseInt(ORACLE_FOREIGN_RPC_SYNC_STATE_CHECK_INTERVAL, 10) || 60000,
   startBlock: parseInt(ORACLE_FOREIGN_START_BLOCK, 10) || 0,
   blockPollingLimit: parseInt(ORACLE_FOREIGN_RPC_BLOCK_POLLING_LIMIT, 10),
   web3: web3Foreign,
+  web3Redundant: web3ForeignRedundant,
+  web3Fallback: web3ForeignFallback,
+  web3Archive: web3ForeignArchive || web3Foreign,
   bridgeContract: foreignContract,
   eventContract: foreignContract,
   reprocessingOptions: {

oracle/config/foreign-sender.config.js

@@ -1,17 +1,14 @@
 const baseConfig = require('./base.config')
 
 const { DEFAULT_TRANSACTION_RESEND_INTERVAL } = require('../src/utils/constants')
-const { web3Foreign, web3ForeignRedundant, web3ForeignFallback } = require('../src/services/web3')
 
 const { ORACLE_FOREIGN_TX_RESEND_INTERVAL } = process.env
 
 module.exports = {
   ...baseConfig,
+  main: baseConfig.foreign,
   queue: 'foreign-prioritized',
   id: 'foreign',
   name: 'sender-foreign',
-  web3: web3Foreign,
-  web3Redundant: web3ForeignRedundant,
-  web3Fallback: web3ForeignFallback,
   resendInterval: parseInt(ORACLE_FOREIGN_TX_RESEND_INTERVAL, 10) || DEFAULT_TRANSACTION_RESEND_INTERVAL
 }

oracle/config/home-sender.config.js

@@ -1,17 +1,14 @@
 const baseConfig = require('./base.config')
 
 const { DEFAULT_TRANSACTION_RESEND_INTERVAL } = require('../src/utils/constants')
-const { web3Home, web3HomeRedundant, web3HomeFallback } = require('../src/services/web3')
 
 const { ORACLE_HOME_TX_RESEND_INTERVAL } = process.env
 
 module.exports = {
   ...baseConfig,
+  main: baseConfig.home,
   queue: 'home-prioritized',
   id: 'home',
   name: 'sender-home',
-  web3: web3Home,
-  web3Redundant: web3HomeRedundant,
-  web3Fallback: web3HomeFallback,
   resendInterval: parseInt(ORACLE_HOME_TX_RESEND_INTERVAL, 10) || DEFAULT_TRANSACTION_RESEND_INTERVAL
 }

oracle/config/information-request-watcher.config.js

@@ -1,11 +1,9 @@
 const baseConfig = require('./base.config')
-const { web3ForeignArchive } = require('../src/services/web3')
 
 const id = `${baseConfig.id}-information-request`
 
 module.exports = {
   ...baseConfig,
-  web3ForeignArchive: web3ForeignArchive || baseConfig.foreign.web3,
   main: baseConfig.home,
   event: 'UserRequestForInformation',
   sender: 'home',

oracle/src/events/processAMBInformationRequests/index.js

@@ -35,11 +35,13 @@ Object.keys(asyncCalls).forEach(method => {
 })
 
 function processInformationRequestsBuilder(config) {
-  const { home, foreign, web3ForeignArchive } = config
+  const { home, foreign } = config
 
   let validatorContract = null
   let blockFinder = null
 
+  foreign.web3Archive.currentProvider.startSyncStateChecker(foreign.syncCheckInterval)
+
   return async function processInformationRequests(informationRequests) {
     const txToSend = []
 
@@ -49,13 +51,15 @@ function processInformationRequestsBuilder(config) {
 
     if (blockFinder === null) {
       rootLogger.debug('Initializing block finder')
-      blockFinder = await makeBlockFinder('foreign', foreign.web3)
+      blockFinder = await makeBlockFinder('foreign', foreign.web3Archive)
     }
 
+    // latest foreign block is requested from an archive RPC, to ensure that it is synced with the network
+    // block confirmations can be requested from the regular JSON RPC
     const foreignBlockNumber =
-      (await getBlockNumber(foreign.web3)) - (await getRequiredBlockConfirmations(foreign.bridgeContract))
+      (await getBlockNumber(foreign.web3Archive)) - (await getRequiredBlockConfirmations(foreign.bridgeContract))
     const homeBlock = await getBlock(home.web3, informationRequests[0].blockNumber)
-    const lastForeignBlock = await getBlock(foreign.web3, foreignBlockNumber)
+    const lastForeignBlock = await getBlock(foreign.web3Archive, foreignBlockNumber)
 
     if (homeBlock.timestamp > lastForeignBlock.timestamp) {
       rootLogger.debug(
@@ -85,7 +89,7 @@ function processInformationRequestsBuilder(config) {
         logger.info({ requestSelector, method: asyncCallMethod, data }, 'Processing async request')
 
         const call = asyncCalls[asyncCallMethod]
-        let [status, result] = await call(web3ForeignArchive, data, foreignClosestBlock).catch(e => {
+        let [status, result] = await call(foreign.web3Archive, data, foreignClosestBlock).catch(e => {
           if (e instanceof HttpListProviderError) {
             throw e
           }

oracle/src/sender.js

@@ -32,8 +32,8 @@ if (process.argv.length < 3) {
 
 const config = require(path.join('../config/', process.argv[2]))
 
-const { web3, web3Fallback } = config
-const web3Redundant = ORACLE_TX_REDUNDANCY === 'true' ? config.web3Redundant : web3
+const { web3, web3Fallback, syncCheckInterval } = config.main
+const web3Redundant = ORACLE_TX_REDUNDANCY === 'true' ? config.main.web3Redundant : web3
 
 const nonceKey = `${config.id}:nonce`
 let chainId = 0
@@ -43,6 +43,7 @@ async function initialize() {
     const checkHttps = checkHTTPS(process.env.ORACLE_ALLOW_HTTP_FOR_RPC, logger)
 
     web3.currentProvider.urls.forEach(checkHttps(config.id))
+    web3.currentProvider.startSyncStateChecker(syncCheckInterval)
 
     GasPrice.start(config.id, web3)
 

oracle/src/services/HttpListProvider.js

@@ -1,5 +1,6 @@
 const fetch = require('node-fetch')
 const promiseRetry = require('promise-retry')
+const { utils } = require('web3')
 const { FALLBACK_RPC_URL_SWITCH_TIMEOUT } = require('../utils/constants')
 
 const { onInjected } = require('./injectedLogger')
@@ -39,19 +40,54 @@ function HttpListProvider(urls, options = {}) {
   this.options = { ...defaultOptions, ...options }
   this.currentIndex = 0
   this.lastTimeUsedPrimary = 0
+  this.latestBlock = 0
+  this.syncStateCheckerIntervalId = 0
 
   onInjected(logger => {
     this.logger = logger.child({ module: `HttpListProvider:${this.options.name}` })
   })
 }
 
-HttpListProvider.prototype.switchToFallbackRPC = function() {
-  if (this.urls.length < 2) {
+HttpListProvider.prototype.startSyncStateChecker = function(syncCheckInterval) {
+  if (this.urls.length > 1 && syncCheckInterval > 0 && this.syncStateCheckerIntervalId === 0) {
+    this.syncStateCheckerIntervalId = setInterval(this.checkLatestBlock.bind(this), syncCheckInterval)
+  }
+}
+
+HttpListProvider.prototype.checkLatestBlock = function() {
+  const payload = { jsonrpc: '2.0', id: 1, method: 'eth_blockNumber', params: [] }
+  this.send(payload, (error, result) => {
+    if (error) {
+      this.logger.warn({ oldBlock: this.latestBlock }, 'Failed to request latest block from all RPC urls')
+    } else if (result.error) {
+      this.logger.warn(
+        { oldBlock: this.latestBlock, error: result.error.message },
+        'Failed to make eth_blockNumber request due to unknown error, switching to fallback RPC'
+      )
+      this.switchToFallbackRPC()
+    } else {
+      const blockNumber = utils.hexToNumber(result.result)
+      if (blockNumber > this.latestBlock) {
+        this.logger.debug({ oldBlock: this.latestBlock, newBlock: blockNumber }, 'Updating latest block number')
+        this.latestBlock = blockNumber
+      } else {
+        this.logger.warn(
+          { oldBlock: this.latestBlock, newBlock: blockNumber },
+          'Latest block on the node was not updated since last request, switching to fallback RPC'
+        )
+        this.switchToFallbackRPC()
+      }
+    }
+  })
+}
+
+HttpListProvider.prototype.switchToFallbackRPC = function(index) {
+  const prevIndex = this.currentIndex
+  const newIndex = index || (prevIndex + 1) % this.urls.length
+  if (this.urls.length < 2 || prevIndex === newIndex) {
     return
   }
 
-  const prevIndex = this.currentIndex
-  const newIndex = (prevIndex + 1) % this.urls.length
   this.logger.info(
     { index: newIndex, oldURL: this.urls[prevIndex], newURL: this.urls[newIndex] },
     'Switching to fallback JSON-RPC URL'
@@ -80,11 +116,7 @@ HttpListProvider.prototype.send = async function send(payload, callback) {
 
     // if some of URLs failed to respond, current URL index is updated to the first URL that responded
     if (currentIndex !== index) {
-      this.logger.info(
-        { index, oldURL: this.urls[currentIndex], newURL: this.urls[index] },
-        'Switching to fallback JSON-RPC URL'
-      )
-      this.currentIndex = index
+      this.switchToFallbackRPC(index)
     }
     callback(null, result)
   } catch (e) {

oracle/src/utils/constants.js

@@ -27,7 +27,6 @@ module.exports = {
   MIN_GAS_PRICE_BUMP_FACTOR: 0.1,
   DEFAULT_TRANSACTION_RESEND_INTERVAL: 20 * 60 * 1000,
   FALLBACK_RPC_URL_SWITCH_TIMEOUT: 60 * 60 * 1000,
-  BLOCK_NUMBER_PROGRESS_ITERATIONS_LIMIT: 10,
   SENDER_QUEUE_MAX_PRIORITY: 10,
   SENDER_QUEUE_SEND_PRIORITY: 5,
   SENDER_QUEUE_CHECK_STATUS_PRIORITY: 1,

oracle/src/watcher.js

@@ -6,11 +6,7 @@ const logger = require('./services/logger')
 const { getShutdownFlag } = require('./services/shutdownState')
 const { getBlockNumber, getRequiredBlockConfirmations, getEvents } = require('./tx/web3')
 const { checkHTTPS, watchdog } = require('./utils/utils')
-const {
-  EXIT_CODES,
-  BLOCK_NUMBER_PROGRESS_ITERATIONS_LIMIT,
-  MAX_HISTORY_BLOCK_TO_REPROCESS
-} = require('./utils/constants')
+const { EXIT_CODES, MAX_HISTORY_BLOCK_TO_REPROCESS } = require('./utils/constants')
 
 if (process.argv.length < 3) {
   logger.error('Please check the number of arguments, config file was not provided')
@@ -38,21 +34,21 @@ const {
   pollingInterval,
   chain,
   reprocessingOptions,
-  blockPollingLimit
+  blockPollingLimit,
+  syncCheckInterval
 } = config.main
 const lastBlockRedisKey = `${config.id}:lastProcessedBlock`
 const lastReprocessedBlockRedisKey = `${config.id}:lastReprocessedBlock`
 const seenEventsRedisKey = `${config.id}:seenEvents`
 let lastProcessedBlock = Math.max(startBlock - 1, 0)
 let lastReprocessedBlock
-let lastSeenBlockNumber = 0
-let sameBlockNumberCounter = 0
 
 async function initialize() {
   try {
     const checkHttps = checkHTTPS(process.env.ORACLE_ALLOW_HTTP_FOR_RPC, logger)
 
     web3.currentProvider.urls.forEach(checkHttps(chain))
+    web3.currentProvider.startSyncStateChecker(syncCheckInterval)
 
     await getLastProcessedBlock()
     await getLastReprocessedBlock()
@@ -225,28 +221,6 @@ async function getLastBlockToProcess(web3, bridgeContract) {
     getBlockNumber(web3),
     getRequiredBlockConfirmations(bridgeContract)
   ])
-
-  if (lastBlockNumber < lastSeenBlockNumber) {
-    sameBlockNumberCounter = 0
-    logger.warn({ lastBlockNumber, lastSeenBlockNumber }, 'Received block number less than already seen block')
-    web3.currentProvider.switchToFallbackRPC()
-  } else if (lastBlockNumber === lastSeenBlockNumber) {
-    sameBlockNumberCounter++
-    if (sameBlockNumberCounter > 1) {
-      logger.info({ lastBlockNumber, sameBlockNumberCounter }, 'Received the same block number more than twice')
-      if (sameBlockNumberCounter >= BLOCK_NUMBER_PROGRESS_ITERATIONS_LIMIT) {
-        sameBlockNumberCounter = 0
-        logger.warn(
-          { lastBlockNumber, n: BLOCK_NUMBER_PROGRESS_ITERATIONS_LIMIT },
-          'Received the same block number for too many times. Probably node is not synced anymore'
-        )
-        web3.currentProvider.switchToFallbackRPC()
-      }
-    }
-  } else {
-    sameBlockNumberCounter = 0
-    lastSeenBlockNumber = lastBlockNumber
-  }
   return lastBlockNumber - requiredBlockConfirmations
 }