From f55f9a46aa6b42e86e3c791a3fc332f8daa453ca Mon Sep 17 00:00:00 2001
From: "CodesBy.Mitch" <osiagomitchell@gmail.com>
Date: Thu, 25 Jun 2026 14:58:06 +0000
Subject: [PATCH] Distributed lock TTL expires during long Stellar operations
 FIXED

---
 src/utils/lock.ts             |  28 +++++++-
 tests/unit/utils/lock.test.ts | 123 ++++++++++++++++++++++++++++++++++
 2 files changed, 150 insertions(+), 1 deletion(-)
 create mode 100644 tests/unit/utils/lock.test.ts

diff --git a/src/utils/lock.ts b/src/utils/lock.ts
index 8c2b1c7..3eb8d7f 100644
--- a/src/utils/lock.ts
+++ b/src/utils/lock.ts
@@ -1,11 +1,12 @@
 import { redis } from "../config/redis.js";
 import { ConflictError } from "./errors.js";
 import crypto from "node:crypto";
+import { logger } from "./logger.js";
 
 export async function withLock<T>(
   key: string,
   fn: () => Promise<T>,
-  ttlMs: number = 10_000
+  ttlMs: number = 30_000
 ): Promise<T> {
   const lockKey = `lock:${key}`;
   const lockValue = crypto.randomUUID();
@@ -21,9 +22,34 @@ export async function withLock<T>(
     throw new ConflictError("Operation in progress, please retry");
   }
 
+  let heartbeat: NodeJS.Timeout | undefined;
+
   try {
+    heartbeat = setInterval(async () => {
+      try {
+        const script = `
+          if redis.call("get", KEYS[1]) == ARGV[1] then
+            return redis.call("pexpire", KEYS[1], ARGV[2])
+          else
+            return 0
+          end
+        `;
+        const result = await redis.eval(script, 1, lockKey, lockValue, ttlMs);
+        if (result !== 1) {
+          logger.warn({ lockKey }, "Lock renewal failed: lock lost or changed");
+          if (heartbeat) {
+            clearInterval(heartbeat);
+            heartbeat = undefined;
+          }
+        }
+      } catch (err) {
+        logger.error({ err, lockKey }, "Error during lock renewal heartbeat");
+      }
+    }, ttlMs / 2);
+
     return await fn();
   } finally {
+    if (heartbeat) clearInterval(heartbeat);
     const script = `
       if redis.call("get", KEYS[1]) == ARGV[1] then
         return redis.call("del", KEYS[1])
diff --git a/tests/unit/utils/lock.test.ts b/tests/unit/utils/lock.test.ts
new file mode 100644
index 0000000..d84a68b
--- /dev/null
+++ b/tests/unit/utils/lock.test.ts
@@ -0,0 +1,123 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { withLock } from "../../../src/utils/lock.js";
+import { redis } from "../../../src/config/redis.js";
+import { ConflictError } from "../../../src/utils/errors.js";
+
+vi.mock("../../../src/config/redis.js", () => ({
+  redis: {
+    set: vi.fn(),
+    eval: vi.fn(),
+  },
+}));
+
+vi.mock("../../../src/utils/logger.js", () => ({
+  logger: {
+    warn: vi.fn(),
+    error: vi.fn(),
+    info: vi.fn(),
+  },
+}));
+
+describe("withLock", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.useFakeTimers();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it("should acquire lock and release it after execution", async () => {
+    (redis.set as any).mockResolvedValue("OK");
+    (redis.eval as any).mockResolvedValue(1);
+
+    const fn = vi.fn().mockResolvedValue("result");
+    const result = await withLock("test", fn);
+
+    expect(result).toBe("result");
+    expect(redis.set).toHaveBeenCalledWith(
+      "lock:test",
+      expect.any(String),
+      "PX",
+      30000,
+      "NX"
+    );
+    // The release eval call should have happened
+    expect(redis.eval).toHaveBeenCalled();
+  });
+
+  it("should throw ConflictError if lock cannot be acquired", async () => {
+    (redis.set as any).mockResolvedValue(null);
+
+    const fn = vi.fn();
+    await expect(withLock("test", fn)).rejects.toThrow("Operation in progress, please retry");
+    expect(fn).not.toHaveBeenCalled();
+  });
+
+  it("should renew lock via heartbeat", async () => {
+    (redis.set as any).mockResolvedValue("OK");
+    (redis.eval as any).mockResolvedValue(1);
+
+    let resolveFn: any;
+    const promise = new Promise((resolve) => {
+      resolveFn = resolve;
+    });
+
+    const fn = vi.fn().mockReturnValue(promise);
+
+    const lockPromise = withLock("test", fn, 10000);
+
+    // Advance time to trigger heartbeat (ttlMs / 2 = 5000)
+    await vi.advanceTimersByTimeAsync(5001);
+    
+    // Check if eval was called for renewal
+    expect(redis.eval).toHaveBeenCalledWith(
+        expect.stringContaining("pexpire"),
+        1,
+        "lock:test",
+        expect.any(String),
+        10000
+    );
+
+    // Trigger another heartbeat
+    await vi.advanceTimersByTimeAsync(5001);
+    // Now it should have been called twice for renewal
+    expect(redis.eval).toHaveBeenCalledTimes(2);
+
+    resolveFn("done");
+    await lockPromise;
+
+    // After completion, it should have called eval one more time for release
+    // But since release is also an eval call, total should be 3
+    expect(redis.eval).toHaveBeenCalledTimes(3);
+  });
+
+  it("should stop heartbeat if renewal fails", async () => {
+    (redis.set as any).mockResolvedValue("OK");
+    // First renewal returns 0 (lock lost)
+    (redis.eval as any).mockResolvedValue(0);
+
+    let resolveFn: any;
+    const promise = new Promise((resolve) => {
+      resolveFn = resolve;
+    });
+
+    const fn = vi.fn().mockReturnValue(promise);
+
+    const lockPromise = withLock("test", fn, 10000);
+
+    await vi.advanceTimersByTimeAsync(5001);
+    expect(redis.eval).toHaveBeenCalledTimes(1);
+
+    // Advance more time, should NOT call eval again because heartbeat should be cleared
+    await vi.advanceTimersByTimeAsync(5001);
+    expect(redis.eval).toHaveBeenCalledTimes(1);
+
+    resolveFn("done");
+    await lockPromise;
+    
+    // Release call happens at the end
+    expect(redis.eval).toHaveBeenCalledTimes(2);
+  });
+});