@aitc/logger

AITC logging utility with requestId and service name support. Built on winston with customizable transports.

Installation

npm install @aitc/logger

Quick Start

const { createLogger } = require("@aitc/logger");

const logger = createLogger({
  level: process.env.LOG_LEVEL || "info",
  service: "property-service",
  transports: ["console", "file"],
  logDir: __dirname,
});

// Use the logger
logger.info("Application started", { requestId: "abc123" });
logger.error("Something went wrong", { error: error.message, requestId: "abc123" });

Configuration Options

createLogger(options)

Creates a logger instance with the following options:

| Option | Type | Default | Description | |--------|------|---------|-------------| | level | string | process.env.LOG_LEVEL \|\| "info" | Log level (info, error, warn, debug) | | service | string | null | Service name to include in logs | | transports | Array | ["console"] | Transport types: "console", "file" | | logDir | string | process.cwd() | Directory for log files (only if file transport enabled) | | errorLogFile | string | "error.log" | Error log filename | | combinedLogFile | string | "combined.log" | Combined log filename |

Usage Examples

Basic Usage (Console Only)

const { createLogger } = require("@aitc/logger");

const logger = createLogger({
  level: "info",
  service: "my-service",
});

logger.info("User logged in", { userId: 123, requestId: "req-456" });
logger.error("Database connection failed", { error: err.message, requestId: "req-456" });

With File Logging

const { createLogger } = require("@aitc/logger");
const path = require("path");

const logger = createLogger({
  level: process.env.LOG_LEVEL || "info",
  service: "property-service",
  transports: ["console", "file"],
  logDir: path.join(__dirname, "logs"),
  errorLogFile: "error.log",
  combinedLogFile: "combined.log",
});

Using Environment Variables

const { createLogger } = require("@aitc/logger");

// LOG_LEVEL is automatically read from process.env
const logger = createLogger({
  service: "auth-service",
  transports: ["console"],
});

Migration from Old Logger

If you're migrating from the old logger that used a config file:

Before:

const logger = require("../utils/logger");
const config = require("../config/config");

After:

const { createLogger } = require("@aitc/logger");
const config = require("../config/config");

const logger = createLogger({
  level: config.log_level || process.env.LOG_LEVEL || "info",
  service: "property-service",
  transports: ["console", "file"],
  logDir: __dirname,
});

API

logger.info(message, meta)

Logs an info message.

Parameters:

• message (string): Log message
• meta (object): Metadata object. Special fields:
  • requestId: Request ID to include in log
  • service: Service name (overrides default service)
  • Any other fields will be JSON stringified

logger.error(message, meta)

Logs an error message.

logger.warn(message, meta)

Logs a warning message.

logger.debug(message, meta)

Logs a debug message.

logger.raw

Access to the underlying winston logger instance for advanced usage.

Log Format

Logs are formatted as:

YYYY-MM-DD HH:mm:ss [LEVEL] [service-name] [request-id: requestId] message {metadata}

Example:

2026-01-09 12:30:45 [INFO] [property-service] [request-id: abc123] User logged in {"userId":123}

Environment Variables

• LOG_LEVEL: Sets the default log level (info, error, warn, debug)

License

ISC

Support

For issues and questions, please contact the AITC development team.