add: dynamic base gas fees

Author: sirpy

src/server/blockchain/BaseAdminWallet.js

@@ -8,8 +8,8 @@ const { base, env } = conf
 const options = {
   ethereum: base,
   network: `${env}-base`,
-  maxFeePerGas: (1e8).toFixed(0),
-  maxPriorityFeePerGas: (1e4).toFixed(0),
+  maxFeePerGas: undefined, // will force use of estimatefees
+  maxPriorityFeePerGas: undefined, // will force use of estimate fees
   fetchGasPrice: false,
   faucetTxCost: 500000
 }

src/server/blockchain/Web3Wallet.js

@@ -960,6 +960,21 @@ export class Web3Wallet {
     }
   }
 
+  async getFeeEstimates() {
+    const result = await this.web3.eth.getFeeHistory('0x5', 'latest', [10])
+
+    const baseFees = result.baseFeePerGas.map(hex => parseInt(hex, 16))
+    const rewards = result.reward.map(r => parseInt(r[0], 16)) // 10th percentile
+
+    const latestBaseFee = baseFees[baseFees.length - 1]
+    const minPriorityFee = Math.min(...rewards)
+
+    return {
+      baseFee: Math.floor(latestBaseFee * 1.1), // in wei
+      priorityFee: minPriorityFee // in wei
+    }
+  }
+
   /**
    * Helper function to handle a tx Send call
    * @param tx
@@ -1011,6 +1026,11 @@ export class Web3Wallet {
       maxFeePerGas = maxFeePerGas || this.maxFeePerGas
       maxPriorityFeePerGas = maxPriorityFeePerGas || this.maxPriorityFeePerGas
 
+      if (!maxFeePerGas || !maxPriorityFeePerGas) {
+        const { baseFee, priorityFee } = await this.getFeeEstimates()
+        maxFeePerGas = maxFeePerGas || baseFee
+        maxPriorityFeePerGas = maxPriorityFeePerGas || priorityFee
+      }
       logger.trace('getting tx lock:', { txuuid })
 
       const { nonce, release, address } = await this.txManager.lock(this.filledAddresses)