z-mmap-logger/dist/index.js

High-performance logging for NestJS using memory-mapped files

"use strict";
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var __importStar = (this && this.__importStar) || function (mod) {
    if (mod && mod.__esModule) return mod;
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    __setModuleDefault(result, mod);
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Object.defineProperty(exports, "__esModule", { value: true });
exports.createZMmapLogger = exports.ZMmapLogger = void 0;
const fs = __importStar(require("fs"));
const path = __importStar(require("path"));
class ZMmapLogger {
    constructor(options) {
        var _a, _b;
        this.offset = 0;
        this.maxSize = 10 * 1024 * 1024; // 10MB
        const maxSize = (_a = options === null || options === void 0 ? void 0 : options.maxSize) !== null && _a !== void 0 ? _a : this.maxSize;
        this.maxSize = maxSize;
        const logDir = (_b = options === null || options === void 0 ? void 0 : options.logDir) !== null && _b !== void 0 ? _b : path.join(process.cwd(), '.z-logs');
        if (!fs.existsSync(logDir)) {
            fs.mkdirSync(logDir, { recursive: true });
        }
        this.logFile = path.join(logDir, 'logs.mmap');
        // Create or open the file
        this.fd = fs.openSync(this.logFile, 'a+');
        const stats = fs.fstatSync(this.fd);
        if (stats.size < this.maxSize) {
            // Pre-allocate buffer space for better performance
            fs.closeSync(this.fd);
            fs.truncateSync(this.logFile, this.maxSize);
            this.fd = fs.openSync(this.logFile, 'r+');
        }
        // Create a buffer that maps to the file
        this.buffer = Buffer.alloc(this.maxSize);
        // Read the file into buffer
        fs.readSync(this.fd, this.buffer, 0, 4, 0);
        // Initialize offset if file is new
        if (this.buffer.readUInt32LE(0) === 0) {
            this.buffer.writeUInt32LE(4, 0); // Offset starts after the header (4 bytes)
            this.offset = 4;
        }
        else {
            this.offset = this.buffer.readUInt32LE(0);
        }
    }
    log(message, context) {
        this.writeLog({ level: 'log', message, context });
    }
    error(message, trace, context) {
        this.writeLog({
            level: 'error',
            message,
            trace,
            context
        });
    }
    warn(message, context) {
        this.writeLog({ level: 'warn', message, context });
    }
    debug(message, context) {
        this.writeLog({ level: 'debug', message, context });
    }
    verbose(message, context) {
        this.writeLog({ level: 'verbose', message, context });
    }
    /**
     * Write a log entry to the memory-mapped file
     */
    writeLog(log) {
        // Create log entry with timestamp
        const logEntry = {
            timestamp: new Date().toISOString(),
            ...log,
        };
        const logString = JSON.stringify(logEntry) + '\n';
        const logBuffer = Buffer.from(logString);
        // Reset offset if we're at the end of the buffer
        if (this.offset + logBuffer.length > this.maxSize) {
            this.offset = 4; // Reset to start (after header)
        }
        // Write the log to our buffer
        logBuffer.copy(this.buffer, this.offset);
        this.offset += logBuffer.length;
        // Update the offset in the header
        this.buffer.writeUInt32LE(this.offset, 0);
        // Sync the buffer to the file
        fs.writeSync(this.fd, this.buffer, 0, this.offset, 0);
    }
    /**
     * Close the file descriptor when the logger is no longer needed
     */
    close() {
        fs.closeSync(this.fd);
    }
}
exports.ZMmapLogger = ZMmapLogger;
// Export a factory function for easy creation
function createZMmapLogger(options) {
    return new ZMmapLogger(options);
}
exports.createZMmapLogger = createZMmapLogger;