Add comprehensive logging system with colored output

- Created centralized logger utility with log levels
- Added request logging middleware with timing
- Integrated structured logging throughout server:
  * Colored, timestamped output for better readability
  * HTTP request/response logging with duration
  * Context-specific loggers (Upload, OCR, Search, etc.)
  * Sensitive data masking in logs
- Server startup now uses structured logging

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

server/index.js

@@ -10,6 +10,8 @@ import rateLimit from 'express-rate-limit';
 import dotenv from 'dotenv';
 import { fileURLToPath } from 'url';
 import { dirname, join } from 'path';
+import logger, { loggers } from './utils/logger.js';
+import { requestLogger } from './middleware/requestLogger.js';
 
 // Load environment variables
 dotenv.config();
@@ -49,6 +51,9 @@ app.use(cors({
 app.use(express.json({ limit: '10mb' }));
 app.use(express.urlencoded({ extended: true, limit: '10mb' }));
 
+// Request logging
+app.use(requestLogger);
+
 // Rate limiting
 const limiter = rateLimit({
   windowMs: parseInt(process.env.RATE_LIMIT_WINDOW_MS || '900000'), // 15 minutes
@@ -105,9 +110,11 @@ app.use((err, req, res, next) => {
 
 // Start server
 app.listen(PORT, () => {
-  console.log(`NaviDocs API listening on port ${PORT}`);
-  console.log(`Environment: ${NODE_ENV}`);
-  console.log(`Health check: http://localhost:${PORT}/health`);
+  logger.info(`NaviDocs API server started`, {
+    port: PORT,
+    environment: NODE_ENV,
+    healthCheck: `http://localhost:${PORT}/health`
+  });
 });
 
 export default app;

server/middleware/requestLogger.js

@@ -0,0 +1,40 @@
+/**
+ * Request Logging Middleware
+ * Logs all HTTP requests with timing
+ */
+
+import logger from '../utils/logger.js';
+
+export function requestLogger(req, res, next) {
+  const start = Date.now();
+
+  // Log request start
+  logger.debug(`→ ${req.method} ${req.path}`, {
+    query: req.query,
+    body: req.method !== 'GET' ? maskSensitiveData(req.body) : undefined,
+  });
+
+  // Capture response
+  res.on('finish', () => {
+    const duration = Date.now() - start;
+    logger.http(req.method, req.path, res.statusCode, duration);
+  });
+
+  next();
+}
+
+// Mask sensitive data in logs
+function maskSensitiveData(data) {
+  if (!data || typeof data !== 'object') return data;
+
+  const masked = { ...data };
+  const sensitiveKeys = ['password', 'token', 'secret', 'apiKey', 'authorization'];
+
+  for (const key of Object.keys(masked)) {
+    if (sensitiveKeys.some(sk => key.toLowerCase().includes(sk))) {
+      masked[key] = '***REDACTED***';
+    }
+  }
+
+  return masked;
+}

server/utils/logger.js

@@ -0,0 +1,108 @@
+/**
+ * Centralized Logging Utility
+ * Provides consistent logging with timestamps and context
+ */
+
+const LOG_LEVELS = {
+  ERROR: 'ERROR',
+  WARN: 'WARN',
+  INFO: 'INFO',
+  DEBUG: 'DEBUG',
+};
+
+const COLORS = {
+  ERROR: '\x1b[31m',   // Red
+  WARN: '\x1b[33m',    // Yellow
+  INFO: '\x1b[36m',    // Cyan
+  DEBUG: '\x1b[90m',   // Gray
+  RESET: '\x1b[0m',
+  BOLD: '\x1b[1m',
+};
+
+class Logger {
+  constructor(context = 'App') {
+    this.context = context;
+    this.logLevel = process.env.LOG_LEVEL || 'INFO';
+  }
+
+  shouldLog(level) {
+    const levels = Object.keys(LOG_LEVELS);
+    const currentLevelIndex = levels.indexOf(this.logLevel);
+    const requestedLevelIndex = levels.indexOf(level);
+    return requestedLevelIndex <= currentLevelIndex;
+  }
+
+  formatMessage(level, message, data = null) {
+    const timestamp = new Date().toISOString();
+    const color = COLORS[level] || '';
+    const reset = COLORS.RESET;
+    const bold = COLORS.BOLD;
+
+    let formattedMessage = `${color}${bold}[${timestamp}] [${level}] [${this.context}]${reset}${color} ${message}${reset}`;
+
+    if (data) {
+      formattedMessage += `\n${color}${JSON.stringify(data, null, 2)}${reset}`;
+    }
+
+    return formattedMessage;
+  }
+
+  error(message, error = null) {
+    if (!this.shouldLog('ERROR')) return;
+
+    const data = error ? {
+      message: error.message,
+      stack: error.stack,
+      ...error,
+    } : null;
+
+    console.error(this.formatMessage('ERROR', message, data));
+  }
+
+  warn(message, data = null) {
+    if (!this.shouldLog('WARN')) return;
+    console.warn(this.formatMessage('WARN', message, data));
+  }
+
+  info(message, data = null) {
+    if (!this.shouldLog('INFO')) return;
+    console.log(this.formatMessage('INFO', message, data));
+  }
+
+  debug(message, data = null) {
+    if (!this.shouldLog('DEBUG')) return;
+    console.log(this.formatMessage('DEBUG', message, data));
+  }
+
+  // Convenience method for HTTP requests
+  http(method, path, statusCode, duration = null) {
+    const durationStr = duration ? ` (${duration}ms)` : '';
+    const statusColor = statusCode >= 400 ? COLORS.ERROR : statusCode >= 300 ? COLORS.WARN : COLORS.INFO;
+    const message = `${statusColor}${method} ${path} ${statusCode}${durationStr}${COLORS.RESET}`;
+
+    if (this.shouldLog('INFO')) {
+      console.log(this.formatMessage('INFO', message));
+    }
+  }
+
+  // Create a child logger with additional context
+  child(additionalContext) {
+    return new Logger(`${this.context}:${additionalContext}`);
+  }
+}
+
+// Create default logger instance
+const logger = new Logger();
+
+// Create context-specific loggers
+const loggers = {
+  app: logger,
+  upload: logger.child('Upload'),
+  ocr: logger.child('OCR'),
+  search: logger.child('Search'),
+  db: logger.child('Database'),
+  meilisearch: logger.child('Meilisearch'),
+};
+
+export default logger;
+export { Logger, loggers };