/**
* Structured logging utility for Kolada MCP Server
* @version 2.1.0
*/
import type { LogLevel, LogEntry } from '../config/types.js';
const LOG_LEVELS: Record<LogLevel, number> = {
debug: 0,
info: 1,
warn: 2,
error: 3,
};
class Logger {
private minLevel: LogLevel;
private serviceName: string;
constructor(serviceName: string = 'kolada-mcp', minLevel: LogLevel = 'info') {
this.serviceName = serviceName;
this.minLevel = (process.env.LOG_LEVEL as LogLevel) || minLevel;
}
private shouldLog(level: LogLevel): boolean {
return LOG_LEVELS[level] >= LOG_LEVELS[this.minLevel];
}
private formatEntry(entry: LogEntry): string {
const base = {
timestamp: entry.timestamp,
level: entry.level.toUpperCase(),
service: this.serviceName,
message: entry.message,
...entry.context,
};
return JSON.stringify(base);
}
private log(level: LogLevel, message: string, context?: Record<string, unknown>): void {
if (!this.shouldLog(level)) return;
const entry: LogEntry = {
timestamp: new Date().toISOString(),
level,
message,
context,
};
// Use stderr for all logs (stdout reserved for MCP protocol)
const output = this.formatEntry(entry);
if (level === 'error') {
console.error(output);
} else {
console.error(output);
}
}
debug(message: string, context?: Record<string, unknown>): void {
this.log('debug', message, context);
}
info(message: string, context?: Record<string, unknown>): void {
this.log('info', message, context);
}
warn(message: string, context?: Record<string, unknown>): void {
this.log('warn', message, context);
}
error(message: string, context?: Record<string, unknown>): void {
this.log('error', message, context);
}
/**
* Log an API request
*/
apiRequest(endpoint: string, params?: Record<string, unknown>): void {
this.debug('API request', { endpoint, params });
}
/**
* Log an API response
*/
apiResponse(endpoint: string, status: number, duration: number): void {
this.debug('API response', { endpoint, status, duration_ms: duration });
}
/**
* Log a tool call
*/
toolCall(toolName: string, args: Record<string, unknown>): void {
this.info('Tool called', { tool: toolName, args });
}
/**
* Log a tool result
*/
toolResult(toolName: string, success: boolean, duration: number): void {
this.info('Tool completed', { tool: toolName, success, duration_ms: duration });
}
/**
* Log cache operations
*/
cacheHit(key: string): void {
this.debug('Cache hit', { key });
}
cacheMiss(key: string): void {
this.debug('Cache miss', { key });
}
cacheSet(key: string, ttl: number): void {
this.debug('Cache set', { key, ttl_ms: ttl });
}
}
// Singleton instance
export const logger = new Logger();
