@aruncodergriphic/logger

A flexible and production-ready logging library for microservices, built on top of pino, with:

• Console, File, and Loki transports
• Colorized & pretty console logs
• Structured JSON logs for files & Loki
• Fastify middleware for request/response logging
• GraphQL Apollo plugin for query/mutation/subscription logging
• Built-in helpers for auth, DB, business events

Designed to work independently or as part of any Fastify-based microservice.

🚀 Installation

pnpm install @aruncodergriphic/logger

📦 Basic Usage

import { createLogger, logger } from '@aruncodergriphic/logger';

// Use the default logger
logger.info('Service started');

// Create a custom logger
const customLogger = createLogger({
  level: 'debug',
  service: 'payment-service',
  environment: 'production',
});
customLogger.debug('Debugging...');

⚡ Features

• Levels: trace, debug, info, warn, error, fatal
• Transports:
  • Console (colorized & pretty by default)
  • File (with rotation support)
  • Loki (Grafana Loki integration, batch & flush)
• Context-aware logging (requestId, userId, etc.)
• Specialized helpers:
  • logger.request(req, res, duration)
  • logger.database(operation, table, duration)
  • logger.auth(action, userId, success)
  • logger.business(event, entityType, entityId)

🔌 Fastify Integration

import Fastify from 'fastify';
import { logger, fastifyLogger } from '@aruncodergriphic/logger';

const app = Fastify({ logger: false });

app.register(fastifyLogger({
  logger,
  includeRequestBody: true,
  includeResponseBody: false,
  excludePaths: ['/health'],
}));

app.get('/ping', async (req, reply) => {
  req.log.info('Ping received');
  return { pong: true };
});

app.listen({ port: 3000 });

🧩 GraphQL Integration (Apollo)

import { ApolloServer } from '@apollo/server';
import { createGraphQLLogger, logger } from '@aruncodergriphic/logger';

const server = new ApolloServer({
  typeDefs,
  resolvers,
  plugins: [
    createGraphQLLogger({
      logger,
      logQueries: true,
      logMutations: true,
      logErrors: true,
      logSlowQueries: true,
      slowQueryThreshold: 1000, // 1s
    }),
  ],
});

📂 File Transport Example

import { createLogger } from '@aruncodergriphic/logger';

const fileLogger = createLogger({
  enableFile: true,
  transports: {
    file: {
      level: 'info',
      filename: './logs/app.log',
      maxSize: '50MB',
      maxFiles: 5,
      format: 'json'
    },
  },
});

fileLogger.info('This will be written to app.log');

📡 Loki Transport Example

import { createLogger } from '@aruncodergriphic/logger';

const lokiLogger = createLogger({
  enableLoki: true,
  transports: {
    loki: {
      level: 'info',
      host: 'http://localhost:3100',
      basicAuth: {
        username: 'admin',
        password: 'secret',
      },
      labels: {
        service: 'order-service',
        environment: 'staging',
      },
      batchSize: 100,
      flushInterval: 5000,
    },
  },
});

lokiLogger.info('Hello from Loki transport!');

⚙️ Environment Variables

| Variable | Description | Default | |----------------------|--------------------------------------|-----------------------| | LOG_LEVEL | Log level (info, debug, etc.) | info | | SERVICE_NAME | Service name | ai-interview-backend| | SERVICE_VERSION | Service version | 1.0.0 | | NODE_ENV | Environment (development, production) | development | | LOG_FILE | Log file path | ./logs/app.log | | LOG_MAX_SIZE | Max log file size | 100MB | | LOG_MAX_FILES | Number of rotated log files | 5 | | LOKI_URL | Loki server URL | — | | LOKI_USERNAME | Loki basic auth username | — | | LOKI_PASSWORD | Loki basic auth password | — | | LOKI_BATCH_SIZE | Loki batch size | 100 | | LOKI_FLUSH_INTERVAL| Loki flush interval (ms) | 5000 |

📝 License

MIT © Arun Singh (@aruncodergriphic)