/**
* Simple structured logger for the Perplexity MCP Server
* Outputs to stderr to avoid interfering with STDIO transport
*/
export enum LogLevel {
DEBUG = 0,
INFO = 1,
WARN = 2,
ERROR = 3,
}
const LOG_LEVEL_NAMES: Record<LogLevel, string> = {
[LogLevel.DEBUG]: "DEBUG",
[LogLevel.INFO]: "INFO",
[LogLevel.WARN]: "WARN",
[LogLevel.ERROR]: "ERROR",
};
/**
* Gets the configured log level from environment variable
* Defaults to ERROR to minimize noise in production
*/
function getLogLevel(): LogLevel {
const level = process.env.PERPLEXITY_LOG_LEVEL?.toUpperCase();
switch (level) {
case "DEBUG":
return LogLevel.DEBUG;
case "INFO":
return LogLevel.INFO;
case "WARN":
return LogLevel.WARN;
case "ERROR":
return LogLevel.ERROR;
default:
return LogLevel.ERROR;
}
}
const currentLogLevel = getLogLevel();
function safeStringify(obj: unknown): string {
try {
return JSON.stringify(obj);
} catch {
return "[Unstringifiable]";
}
}
/**
* Formats a log message with timestamp and level
*/
function formatMessage(level: LogLevel, message: string, meta?: Record<string, unknown>): string {
const timestamp = new Date().toISOString();
const levelName = LOG_LEVEL_NAMES[level];
if (meta && Object.keys(meta).length > 0) {
return `[${timestamp}] ${levelName}: ${message} ${safeStringify(meta)}`;
}
return `[${timestamp}] ${levelName}: ${message}`;
}
/**
* Logs a message if the configured log level allows it
*/
function log(level: LogLevel, message: string, meta?: Record<string, unknown>): void {
if (level >= currentLogLevel) {
const formatted = formatMessage(level, message, meta);
console.error(formatted); // Use stderr to avoid interfering with STDIO
}
}
/**
* Structured logger interface
*/
export const logger = {
debug(message: string, meta?: Record<string, unknown>): void {
log(LogLevel.DEBUG, message, meta);
},
info(message: string, meta?: Record<string, unknown>): void {
log(LogLevel.INFO, message, meta);
},
warn(message: string, meta?: Record<string, unknown>): void {
log(LogLevel.WARN, message, meta);
},
error(message: string, meta?: Record<string, unknown>): void {
log(LogLevel.ERROR, message, meta);
},
};
