/**
* AusLaw MCP - Structured logging utility
* Copyright (c) 2024 Russell Brenner
* Licensed under the MIT License
*
* Provides levelled logging with environment-variable configuration.
*/
export enum LogLevel {
DEBUG = 0,
INFO = 1,
WARN = 2,
ERROR = 3,
}
class Logger {
private level: LogLevel;
constructor(level: LogLevel = LogLevel.INFO) {
this.level = level;
}
/**
* Log a debug-level message (most verbose).
*
* @param message - Human-readable log message
* @param meta - Optional structured metadata
*/
debug(message: string, meta?: Record<string, unknown>): void {
if (this.level <= LogLevel.DEBUG) {
console.error(`[DEBUG] ${message}`, meta ?? "");
}
}
/**
* Log an informational message.
*
* @param message - Human-readable log message
* @param meta - Optional structured metadata
*/
info(message: string, meta?: Record<string, unknown>): void {
if (this.level <= LogLevel.INFO) {
console.error(`[INFO] ${message}`, meta ?? "");
}
}
/**
* Log a warning message.
*
* @param message - Human-readable log message
* @param meta - Optional structured metadata
*/
warn(message: string, meta?: Record<string, unknown>): void {
if (this.level <= LogLevel.WARN) {
console.warn(`[WARN] ${message}`, meta ?? "");
}
}
/**
* Log an error message.
*
* @param message - Human-readable log message
* @param error - The Error or unknown value that triggered this log
* @param meta - Optional structured metadata
*/
error(message: string, error?: Error | unknown, meta?: Record<string, unknown>): void {
if (this.level <= LogLevel.ERROR) {
console.error(`[ERROR] ${message}`, { error, ...meta });
}
}
}
/**
* Parse the LOG_LEVEL environment variable into a {@link LogLevel}.
* Falls back to `INFO` if unset or invalid.
*/
function parseLogLevel(): LogLevel {
const raw = process.env.LOG_LEVEL;
if (raw === undefined) return LogLevel.INFO;
const parsed = parseInt(raw, 10);
if (Number.isNaN(parsed) || parsed < LogLevel.DEBUG || parsed > LogLevel.ERROR) {
return LogLevel.INFO;
}
return parsed as LogLevel;
}
/** Singleton logger instance configured via LOG_LEVEL env var */
export const logger = new Logger(parseLogLevel());
