Using flashbot to submit transaction

package.json

@@ -46,6 +46,7 @@
   },
   "homepage": "https://github.com/cennznet/cennznet#readme",
   "dependencies": {
+    "@flashbots/ethers-provider-bundle": "^0.5.0",
     "@types/chai": "^4.2.19",
     "@types/mocha": "^8.2.2",
     "dotenv": "^8.2.0",

scripts/subscribeEventProof.js

@@ -7,6 +7,7 @@ const mongoose = require('mongoose');
 const { EventProcessed  } = require('../src/mongo/models');
 const ethers = require('ethers');
 const bridgeAbi = require("../abi/CENNZnetBridge.json").abi;
+const { FlashbotsBundleProvider, FlashbotsTransactionResolution} = require("@flashbots/ethers-provider-bundle");
 
 const timeoutMs = 20000;
 const BUFFER = 1000;
@@ -86,16 +87,34 @@ async function getEventPoofAndSubmit(api, eventId, bridge, txExecutor, newValida
             logger.info('percentGasPrice:',percentGasPrice.toString());
             const increasedGasPrice = gasPrice.add(percentGasPrice);
             logger.info('Gas price nw;:', gasPrice.toString());
-
-            const gasEstimated = await bridge.estimateGas.setValidators(newValidators, newValidatorSetId, proof, {gasLimit: 5000000, gasPrice: increasedGasPrice});
             const eventExists = await bridge.eventIds(eventId.toString()); // check storage again, before sending event proof
+            const gasEstimated = await bridge.estimateGas.setValidators(newValidators, newValidatorSetId, proof, {gasLimit: 5000000, gasPrice: increasedGasPrice});
             if (!eventExists) {
-                const tx = await bridge.setValidators(newValidators, newValidatorSetId, proof, {
+                const iface = new ethers.utils.Interface(bridgeAbi);
+                const data = iface.encodeFunctionData("setValidators", [newValidators, newValidatorSetId, proof]);
+                const flashbotsProvider = await FlashbotsBundleProvider.create(provider, txExecutor);
+                const transaction = {
+                    from: txExecutor.address,
+                    to: process.env.BRIDGE_CONTRACT,
+                    data: data,
+                    gasPrice: increasedGasPrice,
                     gasLimit: gasEstimated.add(BUFFER),
-                    gasPrice: increasedGasPrice
+                }
+                const res = await flashbotsProvider.sendPrivateTransaction({
+                    transaction,
+                    txExecutor,
+                }, {
+                    maxBlockNumber: (await provider.getBlockNumber()) + 15, // only allow tx to be mined for the next 15 blocks
                 });
-                await tx.wait(); // wait till tx is mined
-                logger.info(JSON.stringify(tx));
+
+                const waitRes = await res.wait();
+                if (waitRes === FlashbotsTransactionResolution.TransactionIncluded) {
+                    logger.info("Private transaction successfully mined.");
+                    logger.info(JSON.stringify(waitRes));
+                } else if (waitRes === FlashbotsTransactionResolution.TransactionDropped) {
+                    logger.info("Private transaction was not mined and has been removed from the system.");
+                    await sendSlackNotification(`Failed to submit transaction via flashbot`);
+                }
                 await updateLastEventProcessed(eventId, blockHash.toString());
                 const balance = await provider.getBalance(txExecutor.address);
                 logger.info(`IMP Balance is: ${balance}`);
@@ -113,8 +132,7 @@ async function getEventPoofAndSubmit(api, eventId, bridge, txExecutor, newValida
             logger.error(`IMP Error: ${e.stack}`);
             // send slack notification when proof submission fails
             const message = ` 🚨 Issue while submitting validator set on ethereum bridge 
-                    proof: ${JSON.stringify(proof)} 
-                    newValidators: ${newValidators}
+                    event proof id: ${eventProof.eventId} 
                     newValidatorSetId: ${newValidatorSetId}
                     on CENNZnets ${process.env.NETWORK} chain`;
             await sendSlackNotification(message);

yarn.lock

@@ -1089,6 +1089,14 @@
   dependencies:
     ajv "^6.12.6"
 
+"@flashbots/ethers-provider-bundle@^0.5.0":
+  version "0.5.0"
+  resolved "https://registry.yarnpkg.com/@flashbots/ethers-provider-bundle/-/ethers-provider-bundle-0.5.0.tgz#068dd6a078066c50c36ac81b92d4726636768853"
+  integrity sha512-w7vc6aWDtgaHkDSgACjda0NoKYjOJ4mkr2av+u0NctvsoeNTg5dji65zeyU+98Fx3s6IbK0mfUTSGHAUtyt21A==
+  dependencies:
+    ts-node "^9.1.0"
+    typescript "^4.1.2"
+
 "@humanwhocodes/config-array@^0.5.0":
   version "0.5.0"
   resolved "https://registry.yarnpkg.com/@humanwhocodes/config-array/-/config-array-0.5.0.tgz#1407967d4c6eecd7388f83acf1eaf4d0c6e58ef9"
@@ -9782,6 +9790,18 @@ ts-node@^10.0.0:
     source-map-support "^0.5.17"
     yn "3.1.1"
 
+ts-node@^9.1.0:
+  version "9.1.1"
+  resolved "https://registry.yarnpkg.com/ts-node/-/ts-node-9.1.1.tgz#51a9a450a3e959401bda5f004a72d54b936d376d"
+  integrity sha512-hPlt7ZACERQGf03M253ytLY3dHbGNGrAq9qIHWUY9XHYl1z7wYngSr3OQ5xmui8o2AaxsONxIzjafLUiWBo1Fg==
+  dependencies:
+    arg "^4.1.0"
+    create-require "^1.1.0"
+    diff "^4.0.1"
+    make-error "^1.1.1"
+    source-map-support "^0.5.17"
+    yn "3.1.1"
+
 [email protected]:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-2.0.1.tgz#410eb0d113e5b6356490eec749603725b021b43e"
@@ -9894,6 +9914,11 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
+typescript@^4.1.2:
+  version "4.7.4"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.7.4.tgz#1a88596d1cf47d59507a1bcdfb5b9dfe4d488235"
+  integrity sha512-C0WQT0gezHuw6AdY1M2jxUO83Rjf0HP7Sk1DtXj6j1EwkQNZrHAg2XPWlq62oqEhYvONq5pkC2Y9oPljWToLmQ==
+
 typescript@^4.3.4, typescript@^4.3.5:
   version "4.3.5"
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.3.5.tgz#4d1c37cc16e893973c45a06886b7113234f119f4"