@aikidosec/firewall/helpers/LockFile.js

Zen by Aikido is an embedded Application Firewall that autonomously protects Node.js apps against common and critical attacks, provides rate limiting, detects malicious traffic (including bots), and more.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.LockFile = void 0;
const promises_1 = require("fs/promises");
const promises_2 = require("timers/promises");
const path_1 = require("path");
const os_1 = require("os");
const isUnitTest_1 = require("./isUnitTest");
const LOCK_DIR = (0, path_1.join)((0, os_1.tmpdir)(), "zen-test-locks");
class LockFile {
    constructor(name) {
        this.handle = null;
        if (!(0, isUnitTest_1.isUnitTest)()) {
            throw new Error("LockFile can only be used in unit tests");
        }
        this.lockFile = (0, path_1.join)(LOCK_DIR, `${name}.lock`);
    }
    async acquire() {
        // Ensure lock directory exists
        await (0, promises_1.mkdir)(LOCK_DIR, { recursive: true });
        // Use wx flag to create file exclusively (fails if file exists)
        const maxRetries = 1000;
        const retryDelay = 100; // 100ms
        for (let i = 0; i < maxRetries; i++) {
            try {
                this.handle = await (0, promises_1.open)(this.lockFile, "wx");
                return; // Lock acquired successfully
            }
            catch (error) {
                if (error.code === "EEXIST") {
                    // Lock file exists, wait and retry
                    await (0, promises_2.setTimeout)(retryDelay);
                    continue;
                }
                throw error;
            }
        }
        throw new Error(`Failed to acquire lock after ${maxRetries} attempts`);
    }
    async release() {
        if (this.handle) {
            await this.handle.close();
            this.handle = null;
        }
        try {
            await (0, promises_1.unlink)(this.lockFile);
        }
        catch (error) {
            // Ignore ENOENT errors (file already doesn't exist)
            if (error.code !== "ENOENT") {
                throw error;
            }
        }
    }
    async withLock(fn) {
        await this.acquire();
        try {
            return await fn();
        }
        finally {
            await this.release();
        }
    }
}
exports.LockFile = LockFile;