Merge pull request #617 from EYBlockchain/estimate-gas

Better Gas estimation for on-chain calls

Author: Westlad

wallet/src/common-files/utils/contract.js

@@ -10,6 +10,10 @@ const { proposerUrl } = global.config;
 
 const options = global.config.WEB3_OPTIONS;
 
+// This is hardcoded because we just use it for all estimation.
+const gasEstimateEndpoint =
+'https://vqxy02tr5e.execute-api.us-east-2.amazonaws.com/production/estimateGas';
+
 // returns a web3 contract instance
 export async function getContractInstance(contractName, deployedAddress) {
 const web3 = Web3.connection();
@@ -41,18 +45,31 @@ export function getContractAddress(contractName) {
 */
 export async function submitTransaction(unsignedTransaction, contractAddress, fee) {
 const web3 = Web3.connection();
-let gasPrice = 20000000000;
-const gas = (await web3.eth.getBlock('latest')).gasLimit;
-const blockGasPrice = 2 * Number(await web3.eth.getGasPrice());
-if (blockGasPrice > gasPrice) gasPrice = blockGasPrice;
+const blockGasPrice = Number(await web3.eth.getGasPrice());
 const from = await Web3.getAccount();
+let proposedGasPrice = blockGasPrice; // This is the backup value if external estimation fails;
+try {
+// Call the endpoint to estimate the gas fee.
+const res = (await axios.get(gasEstimateEndpoint)).data.result;
+proposedGasPrice = Number(res?.ProposeGasPrice) * 10 ** 9 || blockGasPrice;
+} catch (error) {
+console.log('Gas Estimation Failed: ', error);
+}
+// Estimate the gasLimit
+const gasLimit = await web3.eth.estimateGas({
+from,
+to: contractAddress,
+data: unsignedTransaction,
+});
+
+const gasLimitWithBuffer = Math.ceil(Number(gasLimit) * 1.1); // 10% seems a reasonable buffer.
+
 const tx = {
 from,
 to: contractAddress,
 data: unsignedTransaction,
-gas: web3.utils.toHex(gas),
-gasPrice: web3.utils.toHex(gasPrice),
-// maxPriorityFeePerGas: web3.utils.toHex(1 * 10 ** 9),
+gas: web3.utils.toHex(gasLimitWithBuffer),
+gasPrice: web3.utils.toHex(proposedGasPrice),
 };
 
 if (fee) tx.value = web3.utils.toHex(fee);