type LogLevel = "debug" | "info" | "warn" | "error";
type LoggerConfig = {
level: LogLevel;
prefix?: string;
};
const LOG_LEVELS: Record<LogLevel, number> = {
debug: 0,
info: 1,
warn: 2,
error: 3,
};
function createLogger(config: LoggerConfig) {
const currentLevel = LOG_LEVELS[config.level];
const prefix = config.prefix ? `[${config.prefix}] ` : "";
function shouldLog(level: LogLevel): boolean {
return LOG_LEVELS[level] >= currentLevel;
}
function formatMessage(level: LogLevel, message: string): string {
const timestamp = new Date().toISOString();
return `${timestamp} ${level.toUpperCase().padEnd(5)} ${prefix}${message}`;
}
return {
debug(message: string): void {
if (shouldLog("debug")) {
process.stderr.write(formatMessage("debug", message) + "\n");
}
},
info(message: string): void {
if (shouldLog("info")) {
process.stderr.write(formatMessage("info", message) + "\n");
}
},
warn(message: string): void {
if (shouldLog("warn")) {
process.stderr.write(formatMessage("warn", message) + "\n");
}
},
error(message: string, error?: unknown): void {
if (shouldLog("error")) {
let msg = formatMessage("error", message);
if (error instanceof Error) {
msg += `: ${error.message}`;
} else if (error !== undefined) {
msg += `: ${String(error)}`;
}
process.stderr.write(msg + "\n");
}
},
};
}
const logLevel = (process.env.LOG_LEVEL as LogLevel) || "info";
export const logger = createLogger({ level: logLevel, prefix: "mcpfs" });
