loki-logger-node

Lightweight Node.js logger for Grafana Loki — simple, fast, and easy to integrate.

Installation

 npm install loki-logger-node

Quick start

import { loki } from 'loki-logger-node';

const logger = loki({ name: 'my-service', stage: 'production', url: '[http://loki:3100](http://loki:3100)', pattern: 'default' });

logger.info('Bootstrap', 'Application started');

await logger.flush();

API

loki(config)

Creates or returns a logger instance.

const logger = loki({ name: 'my-service', stage: 'production', url: '[http://loki:3100](http://loki:3100)' });

Configuration

type LokiSetting = { url: string | URL; name: string; stage?: string; pattern?: string; job?: string; headers?: Record<string, string>; };

| Option | Required | Description | |---|---:|---| | url | Yes | Base Loki URL, for example http://loki:3100 or https://loki.example.com | | name | Yes | Service/application name sent as the lambda_name Loki label | | stage | No | Environment/stage sent as the env Loki label | | pattern | No | Log pattern sent as the log_pattern Loki label | | job | No | Loki job label. Defaults to lambda_logs | | headers | No | Custom HTTP headers for auth or tenancy |

HTTPS Loki endpoint

import { loki } from 'loki-logger-node';

const logger = loki({ name: 'my-service', stage: 'production', url: '[https://loki.example.com](https://loki.example.com)' });

logger.info('Bootstrap', 'Application started');

await logger.flush();

Custom headers and authentication

import { loki } from 'loki-logger-node';

const logger = loki({ name: 'my-service', stage: 'production', url: '[https://loki.example.com](https://loki.example.com)', headers: { Authorization: `Bearer ${process.env.LOKI_TOKEN}`, 'X-Scope-OrgID': 'my-tenant' } });

logger.info('Bootstrap', 'Application started');

await logger.flush();

Logger methods

logger.trace(context, message, ...params);
logger.debug(context, message, ...params);
logger.info(context, message, ...params);
logger.warn(context, message, ...params);
logger.error(context, message, ...params);
logger.fatal(context, message, ...params);

Example:

logger.info('UserService', 'User created', { userId: '123' });

Optional params are included in the JSON log body, not as Loki labels.

Sending logs

Logs are queued in memory until flushed.

await logger.flush();

For backward compatibility, execute() is also available: