+signup +login

frontend/pshared/lib/service/authorization/circuit_breaker.dart

@@ -0,0 +1,92 @@
+import 'package:logging/logging.dart';
+
+/// Circuit breaker pattern implementation for authentication service failures
+class AuthCircuitBreaker {
+  static final _logger = Logger('service.auth_circuit_breaker');
+  
+  static int _failureCount = 0;
+  static DateTime? _lastFailure;
+  static const int _failureThreshold = 3;
+  static const Duration _recoveryTime = Duration(minutes: 5);
+  
+  /// Returns true if the circuit breaker is open (blocking operations)
+  static bool get isOpen {
+    if (_failureCount < _failureThreshold) return false;
+    if (_lastFailure == null) return false;
+    
+    final isOpen = DateTime.now().difference(_lastFailure!) < _recoveryTime;
+    if (isOpen) {
+      _logger.warning('Circuit breaker is OPEN. Failure count: $_failureCount, last failure: $_lastFailure');
+    }
+    return isOpen;
+  }
+  
+  /// Returns true if the circuit breaker is in half-open state (allowing test requests)
+  static bool get isHalfOpen {
+    if (_failureCount < _failureThreshold) return false;
+    if (_lastFailure == null) return false;
+    
+    return DateTime.now().difference(_lastFailure!) >= _recoveryTime;
+  }
+  
+  /// Executes an operation with circuit breaker protection
+  static Future<T> execute<T>(Future<T> Function() operation) async {
+    if (isOpen) {
+      final timeSinceFailure = _lastFailure != null 
+        ? DateTime.now().difference(_lastFailure!)
+        : Duration.zero;
+      final timeUntilRecovery = _recoveryTime - timeSinceFailure;
+      
+      _logger.warning('Circuit breaker blocking operation. Recovery in: ${timeUntilRecovery.inSeconds}s');
+      throw Exception('Auth service temporarily unavailable. Try again in ${timeUntilRecovery.inMinutes} minutes.');
+    }
+    
+    try {
+      _logger.fine('Executing operation through circuit breaker');
+      final result = await operation();
+      _reset();
+      return result;
+    } catch (e) {
+      _recordFailure();
+      rethrow;
+    }
+  }
+  
+  /// Records a failure and updates the circuit breaker state
+  static void _recordFailure() {
+    _failureCount++;
+    _lastFailure = DateTime.now();
+    _logger.warning('Auth circuit breaker recorded failure #$_failureCount at $_lastFailure');
+    
+    if (_failureCount >= _failureThreshold) {
+      _logger.severe('Auth circuit breaker OPENED after $_failureCount failures');
+    }
+  }
+  
+  /// Resets the circuit breaker to closed state
+  static void _reset() {
+    if (_failureCount > 0) {
+      _logger.info('Auth circuit breaker CLOSED - resetting failure count from $_failureCount to 0');
+    }
+    _failureCount = 0;
+    _lastFailure = null;
+  }
+  
+  /// Manual reset (for testing or administrative purposes)
+  static void manualReset() {
+    _logger.info('Auth circuit breaker manually reset');
+    _reset();
+  }
+  
+  /// Get current status for debugging
+  static Map<String, dynamic> getStatus() {
+    return {
+      'failureCount': _failureCount,
+      'lastFailure': _lastFailure?.toIso8601String(),
+      'isOpen': isOpen,
+      'isHalfOpen': isHalfOpen,
+      'threshold': _failureThreshold,
+      'recoveryTime': _recoveryTime.inSeconds,
+    };
+  }
+}