/**
* Logger utility for mcpGraph
*
* All logging goes to stderr to avoid interfering with MCP server
* communication which uses stdout.
*/
type LogLevel = 'debug' | 'info' | 'warn' | 'error';
export interface LogEntry {
level: string;
message: string;
timestamp: string;
args?: unknown[];
}
interface Logger {
debug(message: string, ...args: unknown[]): void;
info(message: string, ...args: unknown[]): void;
warn(message: string, ...args: unknown[]): void;
error(message: string, ...args: unknown[]): void;
startCollection(): void;
stopCollection(): LogEntry[];
}
class LogCollector {
private entries: LogEntry[] = [];
addEntry(level: string, message: string, timestamp: string, args?: unknown[]): void {
this.entries.push({
level,
message,
timestamp,
args: args && args.length > 0 ? args : undefined,
});
}
getEntries(): LogEntry[] {
return [...this.entries];
}
clear(): void {
this.entries = [];
}
}
class ConsoleLogger implements Logger {
private collector: LogCollector | null = null;
private formatMessage(level: LogLevel, message: string): string {
const timestamp = new Date().toISOString();
return `[${timestamp}] [${level.toUpperCase()}] ${message}`;
}
private log(level: LogLevel, message: string, ...args: unknown[]): void {
const timestamp = new Date().toISOString();
const formattedMessage = this.formatMessage(level, message);
const logFn = level === 'error' ? console.error : console.warn;
// Always log to stderr
if (args.length > 0) {
logFn(formattedMessage, ...args);
} else {
logFn(formattedMessage);
}
// Also collect if collection is active
if (this.collector) {
this.collector.addEntry(level, message, timestamp, args.length > 0 ? args : undefined);
}
}
debug(message: string, ...args: unknown[]): void {
this.log('debug', message, ...args);
}
info(message: string, ...args: unknown[]): void {
this.log('info', message, ...args);
}
warn(message: string, ...args: unknown[]): void {
this.log('warn', message, ...args);
}
error(message: string, ...args: unknown[]): void {
this.log('error', message, ...args);
}
startCollection(): void {
this.collector = new LogCollector();
}
stopCollection(): LogEntry[] {
if (!this.collector) {
return [];
}
const entries = this.collector.getEntries();
this.collector = null;
return entries;
}
}
// Export a singleton logger instance
export const logger = new ConsoleLogger();
