feat(experimental): Add an env var to limit the max gas price for resends (#800)

* set max gas price per wei

* bigMath

* add unit tests

* rename

Author: arcoraven

src/tests/math.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { getPercentile } from "../utils/math";
+import { bigMath, getPercentile } from "../utils/math";
 
 describe("getPercentile", () => {
   it("should correctly calculate the p50 (median) of a sorted array", () => {
@@ -27,3 +27,81 @@ describe("getPercentile", () => {
     expect(getPercentile(numbers, 50)).toBe(0);
   });
 });
+
+describe("bigMath", () => {
+  describe("min", () => {
+    it("should return the smaller of two positive numbers", () => {
+      const a = 5n;
+      const b = 10n;
+      expect(bigMath.min(a, b)).toBe(5n);
+    });
+
+    it("should return the smaller of two negative numbers", () => {
+      const a = -10n;
+      const b = -5n;
+      expect(bigMath.min(a, b)).toBe(-10n);
+    });
+
+    it("should handle equal numbers", () => {
+      const a = 5n;
+      const b = 5n;
+      expect(bigMath.min(a, b)).toBe(5n);
+    });
+
+    it("should handle zero and positive number", () => {
+      const a = 0n;
+      const b = 5n;
+      expect(bigMath.min(a, b)).toBe(0n);
+    });
+
+    it("should handle zero and negative number", () => {
+      const a = 0n;
+      const b = -5n;
+      expect(bigMath.min(a, b)).toBe(-5n);
+    });
+
+    it("should handle very large numbers", () => {
+      const a = BigInt(Number.MAX_SAFE_INTEGER) * 2n;
+      const b = BigInt(Number.MAX_SAFE_INTEGER);
+      expect(bigMath.min(a, b)).toBe(b);
+    });
+  });
+
+  describe("max", () => {
+    it("should return the larger of two positive numbers", () => {
+      const a = 5n;
+      const b = 10n;
+      expect(bigMath.max(a, b)).toBe(10n);
+    });
+
+    it("should return the larger of two negative numbers", () => {
+      const a = -10n;
+      const b = -5n;
+      expect(bigMath.max(a, b)).toBe(-5n);
+    });
+
+    it("should handle equal numbers", () => {
+      const a = 5n;
+      const b = 5n;
+      expect(bigMath.max(a, b)).toBe(5n);
+    });
+
+    it("should handle zero and positive number", () => {
+      const a = 0n;
+      const b = 5n;
+      expect(bigMath.max(a, b)).toBe(5n);
+    });
+
+    it("should handle zero and negative number", () => {
+      const a = 0n;
+      const b = -5n;
+      expect(bigMath.max(a, b)).toBe(0n);
+    });
+
+    it("should handle very large numbers", () => {
+      const a = BigInt(Number.MAX_SAFE_INTEGER) * 2n;
+      const b = BigInt(Number.MAX_SAFE_INTEGER);
+      expect(bigMath.max(a, b)).toBe(a);
+    });
+  });
+});

src/utils/env.ts

@@ -102,10 +102,12 @@ export const env = createEnv({
     /**
      * Experimental env vars. These may be renamed or removed in future non-major releases.
      */
-    // Sets how long the mine worker waits for a transaction receipt before considering the transaction dropped (default: 30 minutes).
+    // Sets how long the mine worker waits for a transaction receipt before considering the transaction dropped. Default: 30 minutes
     EXPERIMENTAL__MINE_WORKER_TIMEOUT_SECONDS: z.coerce
       .number()
       .default(30 * 60),
+    // Sets the max gas price for a transaction attempt. Most RPCs reject transactions above a certain gas price. Default: 10^18 wei.
+    EXPERIMENTAL__MAX_GAS_PRICE_WEI: z.coerce.number().default(10 ** 18),
   },
   clientPrefix: "NEVER_USED",
   client: {},
@@ -144,6 +146,8 @@ export const env = createEnv({
     NONCE_MAP_COUNT: process.env.NONCE_MAP_COUNT,
     EXPERIMENTAL__MINE_WORKER_TIMEOUT_SECONDS:
       process.env.EXPERIMENTAL__MINE_WORKER_TIMEOUT_SECONDS,
+    EXPERIMENTAL__MAX_GAS_PRICE_WEI:
+      process.env.EXPERIMENTAL__MAX_GAS_PRICE_WEI,
     METRICS_PORT: process.env.METRICS_PORT,
     METRICS_ENABLED: process.env.METRICS_ENABLED,
   },

src/utils/math.ts

@@ -7,3 +7,8 @@ export const getPercentile = (arr: number[], percentile: number): number => {
   const index = Math.floor((percentile / 100) * (arr.length - 1));
   return arr[index];
 };
+
+export const BigIntMath = {
+  min: (a: bigint, b: bigint) => (a < b ? a : b),
+  max: (a: bigint, b: bigint) => (a > b ? a : b),
+};

src/worker/tasks/sendTransactionWorker.ts

@@ -39,6 +39,7 @@ import {
   isReplacementGasFeeTooLow,
   wrapError,
 } from "../../utils/error";
+import { BigIntMath } from "../../utils/math";
 import { getChecksumAddress } from "../../utils/primitiveTypes";
 import { recordMetrics } from "../../utils/prometheus";
 import { redis } from "../../utils/redis/redis";
@@ -565,34 +566,37 @@ const _minutesFromNow = (minutes: number) =>
  * @param populatedTransaction The transaction with estimated gas from RPC.
  * @param resendCount The resend attempt #. Example: 2 = the transaction was initially sent, then resent once. This is the second resend attempt.
  */
-export const _updateGasFees = (
+export function _updateGasFees(
   populatedTransaction: PopulatedTransaction,
   resendCount: number,
   overrides: SentTransaction["overrides"],
-): PopulatedTransaction => {
+): PopulatedTransaction {
   if (resendCount === 0) {
     return populatedTransaction;
   }
 
-  const multiplier = BigInt(Math.min(10, resendCount * 2));
-
+  const multiplier = BigIntMath.min(10n, BigInt(resendCount) * 2n);
   const updated = { ...populatedTransaction };
 
   // Update gas fees (unless they were explicitly overridden).
+  // Do not exceed MAX_GAS_PRICE_WEI.
+  const MAX_GAS_PRICE_WEI = BigInt(env.EXPERIMENTAL__MAX_GAS_PRICE_WEI);
 
   if (updated.gasPrice && !overrides?.gasPrice) {
-    updated.gasPrice *= multiplier;
+    const newGasPrice = updated.gasPrice * multiplier;
+    updated.gasPrice = BigIntMath.min(newGasPrice, MAX_GAS_PRICE_WEI);
   }
   if (updated.maxPriorityFeePerGas && !overrides?.maxPriorityFeePerGas) {
     updated.maxPriorityFeePerGas *= multiplier;
   }
   if (updated.maxFeePerGas && !overrides?.maxFeePerGas) {
-    updated.maxFeePerGas =
+    const newMaxFeePerGas =
       updated.maxFeePerGas * 2n + (updated.maxPriorityFeePerGas ?? 0n);
+    updated.maxFeePerGas = BigIntMath.min(newMaxFeePerGas, MAX_GAS_PRICE_WEI);
   }
 
   return updated;
-};
+}
 
 // Must be explicitly called for the worker to run on this host.
 export const initSendTransactionWorker = () => {