@gati-framework/observability/dist/loki/logger.js

Observability stack for Gati framework - Prometheus, Grafana, Loki, and Tracing

import winston from 'winston';
import LokiTransport from 'winston-loki';
export class LokiLogger {
    logger;
    lokiTransport;
    constructor(config) {
        this.lokiTransport = new LokiTransport({
            host: config.host,
            basicAuth: config.basicAuth,
            labels: {
                app: 'gati',
                ...config.labels,
            },
            batching: config.batching !== false,
            interval: config.interval || 5000,
            json: true,
        });
        this.logger = winston.createLogger({
            level: 'info',
            format: winston.format.combine(winston.format.timestamp(), winston.format.errors({ stack: true }), winston.format.json()),
            transports: [
                this.lokiTransport,
                new winston.transports.Console({
                    format: winston.format.combine(winston.format.colorize(), winston.format.simple()),
                }),
            ],
        });
    }
    info(message, meta) {
        this.logger.info(message, meta);
    }
    warn(message, meta) {
        this.logger.warn(message, meta);
    }
    error(message, error, meta) {
        this.logger.error(message, {
            error: error?.message,
            stack: error?.stack,
            ...meta,
        });
    }
    debug(message, meta) {
        this.logger.debug(message, meta);
    }
    child(labels) {
        const transport = this.lokiTransport;
        const childLogger = new LokiLogger({
            host: transport.host || 'http://localhost:3100',
            basicAuth: transport.basicAuth,
            labels: {
                ...(transport.labels || {}),
                ...labels,
            },
            batching: transport.batching !== false,
            interval: transport.interval || 5000,
        });
        return childLogger;
    }
    async flush() {
        await new Promise((resolve) => {
            this.logger.on('finish', resolve);
            this.logger.end();
        });
    }
}
export function createLokiMiddleware(logger) {
    return (req, res, next) => {
        const start = Date.now();
        res.on('finish', () => {
            const duration = Date.now() - start;
            logger.info('HTTP Request', {
                method: req.method,
                path: req.path,
                statusCode: res.statusCode,
                duration,
                userAgent: req.get('user-agent'),
                ip: req.ip,
            });
        });
        next();
    };
}