Add scraperLogger.js with credential redaction

Implement structured JSON logging module for the scraper service:
- createLogger(jobId) factory function for job-scoped logging
- info(), warn(), error() methods with consistent JSON output
- Automatic redaction of MongoDB connection string credentials
- Redaction of sensitive keys (password, secret, token, apikey, authorization)
- Message truncation to prevent log bloat (1000 char limit)
- Circular reference handling
- Buffer object representation as [Buffer: N bytes]

Includes comprehensive test suite with 35 test cases covering:
- Log entry format validation (timestamp, level, message, jobId, context)
- MongoDB URI redaction for both mongodb:// and mongodb+srv://
- Sensitive key redaction
- Edge cases (null, undefined, nested objects, arrays)
- Buffer and circular reference handling

__tests__/scraper/scraperLogger.test.js

@@ -0,0 +1,471 @@
+/**
+ * Tests for scraperLogger.js
+ * Following TDD - these tests are written BEFORE implementation
+ */
+
+const { createLogger, LEVELS } = require('../../services/scraperLogger');
+
+describe('scraperLogger', () => {
+  let consoleSpy;
+  let logOutput;
+
+  beforeEach(() => {
+    logOutput = [];
+    consoleSpy = jest.spyOn(console, 'log').mockImplementation((output) => {
+      logOutput.push(output);
+    });
+  });
+
+  afterEach(() => {
+    consoleSpy.mockRestore();
+  });
+
+  describe('createLogger', () => {
+    test('should return an object with info, warn, error methods', () => {
+      const logger = createLogger('test-job-id');
+
+      expect(typeof logger).toBe('object');
+      expect(typeof logger.info).toBe('function');
+      expect(typeof logger.warn).toBe('function');
+      expect(typeof logger.error).toBe('function');
+    });
+
+    test('should include jobId in all log entries', () => {
+      const jobId = 'unique-job-123';
+      const logger = createLogger(jobId);
+
+      logger.info('Test message');
+
+      expect(logOutput.length).toBe(1);
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.jobId).toBe(jobId);
+    });
+  });
+
+  describe('log entry format', () => {
+    test('should include timestamp in ISO format', () => {
+      const logger = createLogger('test-job');
+      const beforeTime = new Date().toISOString();
+
+      logger.info('Test message');
+
+      const afterTime = new Date().toISOString();
+      const parsed = JSON.parse(logOutput[0]);
+
+      expect(parsed.timestamp).toBeDefined();
+      // Verify timestamp is in ISO format
+      expect(parsed.timestamp).toMatch(/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z$/);
+      // Verify timestamp is within test window
+      expect(parsed.timestamp >= beforeTime).toBe(true);
+      expect(parsed.timestamp <= afterTime).toBe(true);
+    });
+
+    test('should include log level', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('Info message');
+      logger.warn('Warn message');
+      logger.error('Error message');
+
+      expect(logOutput.length).toBe(3);
+
+      const infoEntry = JSON.parse(logOutput[0]);
+      const warnEntry = JSON.parse(logOutput[1]);
+      const errorEntry = JSON.parse(logOutput[2]);
+
+      expect(infoEntry.level).toBe('info');
+      expect(warnEntry.level).toBe('warn');
+      expect(errorEntry.level).toBe('error');
+    });
+
+    test('should include message', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('Test message content');
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.message).toBe('Test message content');
+    });
+
+    test('should include context when provided', () => {
+      const logger = createLogger('test-job');
+      const context = { key: 'value', count: 42 };
+
+      logger.info('Test message', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context).toEqual(context);
+    });
+
+    test('should output valid JSON', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('Test message', { data: 'test' });
+
+      expect(() => JSON.parse(logOutput[0])).not.toThrow();
+    });
+  });
+
+  describe('log levels', () => {
+    test('info() should output with level "info"', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('Info message');
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.level).toBe('info');
+    });
+
+    test('warn() should output with level "warn"', () => {
+      const logger = createLogger('test-job');
+
+      logger.warn('Warning message');
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.level).toBe('warn');
+    });
+
+    test('error() should output with level "error"', () => {
+      const logger = createLogger('test-job');
+
+      logger.error('Error message');
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.level).toBe('error');
+    });
+  });
+
+  describe('LEVELS constant', () => {
+    test('should export LEVELS constant with info, warn, error', () => {
+      expect(LEVELS).toBeDefined();
+      expect(LEVELS.info).toBe('info');
+      expect(LEVELS.warn).toBe('warn');
+      expect(LEVELS.error).toBe('error');
+    });
+  });
+
+  describe('message truncation', () => {
+    test('should truncate messages longer than 1000 characters', () => {
+      const logger = createLogger('test-job');
+      const longMessage = 'x'.repeat(1500);
+
+      logger.info(longMessage);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.message.length).toBeLessThanOrEqual(1020); // 1000 + "... [truncated]"
+      expect(parsed.message).toContain('... [truncated]');
+    });
+
+    test('should not truncate messages of 1000 characters or less', () => {
+      const logger = createLogger('test-job');
+      const shortMessage = 'x'.repeat(1000);
+
+      logger.info(shortMessage);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.message).toBe(shortMessage);
+      expect(parsed.message).not.toContain('... [truncated]');
+    });
+
+    test('should handle empty message', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('');
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.message).toBe('');
+    });
+
+    test('should handle null or undefined message', () => {
+      const logger = createLogger('test-job');
+
+      logger.info(null);
+      logger.info(undefined);
+
+      expect(logOutput.length).toBe(2);
+      // Should not throw and should handle gracefully
+    });
+  });
+
+  describe('MongoDB connection string redaction', () => {
+    test('should redact username and password from mongodb:// URIs', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        uri: 'mongodb://admin:secretpassword123@localhost:27017/mydb'
+      };
+
+      logger.info('Database connection', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.uri).toBe('mongodb://[user]:[REDACTED]@localhost:27017/mydb');
+      expect(parsed.context.uri).not.toContain('admin');
+      expect(parsed.context.uri).not.toContain('secretpassword123');
+    });
+
+    test('should redact username and password from mongodb+srv:// URIs', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        uri: 'mongodb+srv://myuser:mypass@cluster0.example.mongodb.net/testdb'
+      };
+
+      logger.info('Database connection', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.uri).toBe('mongodb+srv://[user]:[REDACTED]@cluster0.example.mongodb.net/testdb');
+      expect(parsed.context.uri).not.toContain('myuser');
+      expect(parsed.context.uri).not.toContain('mypass');
+    });
+
+    test('should handle connection string without credentials', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        uri: 'mongodb://localhost:27017/mydb'
+      };
+
+      logger.info('Database connection', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.uri).toBe('mongodb://localhost:27017/mydb');
+    });
+  });
+
+  describe('sensitive key redaction', () => {
+    test('should redact keys containing "password"', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        password: 'secret123',
+        userPassword: 'anotherSecret',
+        password_hash: 'hashed'
+      };
+
+      logger.info('User data', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.password).toBe('[REDACTED]');
+      expect(parsed.context.userPassword).toBe('[REDACTED]');
+      expect(parsed.context.password_hash).toBe('[REDACTED]');
+    });
+
+    test('should redact keys containing "secret"', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        secret: 'mysecret',
+        clientSecret: 'secret123',
+        SECRET_KEY: 'key'
+      };
+
+      logger.info('Config data', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.secret).toBe('[REDACTED]');
+      expect(parsed.context.clientSecret).toBe('[REDACTED]');
+      // Case-insensitive check
+    });
+
+    test('should redact keys containing "token"', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        token: 'abc123',
+        accessToken: 'token456',
+        refresh_token: 'refresh789'
+      };
+
+      logger.info('Auth data', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.token).toBe('[REDACTED]');
+      expect(parsed.context.accessToken).toBe('[REDACTED]');
+      expect(parsed.context.refresh_token).toBe('[REDACTED]');
+    });
+
+    test('should redact keys containing "apikey"', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        apikey: 'key123',
+        apiKey: 'key456',
+        api_key: 'key789' // Note: underscores may not match 'apikey'
+      };
+
+      logger.info('API data', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.apikey).toBe('[REDACTED]');
+      expect(parsed.context.apiKey).toBe('[REDACTED]');
+    });
+
+    test('should redact keys containing "authorization"', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        authorization: 'Bearer token123',
+        Authorization: 'Basic base64string'
+      };
+
+      logger.info('Header data', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.authorization).toBe('[REDACTED]');
+    });
+
+    test('should not redact non-sensitive keys', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        username: 'john',
+        email: 'john@example.com',
+        count: 42
+      };
+
+      logger.info('User info', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.username).toBe('john');
+      expect(parsed.context.email).toBe('john@example.com');
+      expect(parsed.context.count).toBe(42);
+    });
+  });
+
+  describe('circular reference handling', () => {
+    test('should handle circular references in context', () => {
+      const logger = createLogger('test-job');
+      const context = { name: 'test' };
+      context.self = context; // Create circular reference
+
+      // Should not throw
+      expect(() => {
+        logger.info('Circular test', context);
+      }).not.toThrow();
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.name).toBe('test');
+      expect(parsed.context.self).toBe('[Circular]');
+    });
+
+    test('should handle deeply nested circular references', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        level1: {
+          level2: {
+            level3: {}
+          }
+        }
+      };
+      context.level1.level2.level3.back = context.level1;
+
+      expect(() => {
+        logger.info('Deep circular test', context);
+      }).not.toThrow();
+
+      // Should be valid JSON output
+      expect(() => JSON.parse(logOutput[0])).not.toThrow();
+    });
+  });
+
+  describe('Buffer handling', () => {
+    test('should represent Buffer objects as "[Buffer: N bytes]"', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        data: Buffer.from('Hello World')
+      };
+
+      logger.info('Buffer data', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.data).toBe('[Buffer: 11 bytes]');
+    });
+
+    test('should handle empty Buffer', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        data: Buffer.alloc(0)
+      };
+
+      logger.info('Empty buffer', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.data).toBe('[Buffer: 0 bytes]');
+    });
+
+    test('should handle large Buffer', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        data: Buffer.alloc(1024 * 1024) // 1MB buffer
+      };
+
+      logger.info('Large buffer', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.data).toBe('[Buffer: 1048576 bytes]');
+    });
+  });
+
+  describe('edge cases', () => {
+    test('should handle empty context object', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('Test message', {});
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context).toEqual({});
+    });
+
+    test('should handle context not provided', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('Test message');
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context).toEqual({});
+    });
+
+    test('should handle null context', () => {
+      const logger = createLogger('test-job');
+
+      logger.info('Test message', null);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context).toEqual({});
+    });
+
+    test('should handle undefined values in context', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        defined: 'value',
+        undefinedValue: undefined
+      };
+
+      logger.info('Test message', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.defined).toBe('value');
+      // undefined is typically converted to null in JSON
+      expect(parsed.context.undefinedValue).toBeNull();
+    });
+
+    test('should handle nested objects in context', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        outer: {
+          inner: {
+            value: 'deep'
+          }
+        }
+      };
+
+      logger.info('Nested test', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.outer.inner.value).toBe('deep');
+    });
+
+    test('should handle arrays in context', () => {
+      const logger = createLogger('test-job');
+      const context = {
+        items: [1, 2, 3, 'four']
+      };
+
+      logger.info('Array test', context);
+
+      const parsed = JSON.parse(logOutput[0]);
+      expect(parsed.context.items).toEqual([1, 2, 3, 'four']);
+    });
+  });
+});