跨境云架构：分布式智能DNS最优节点，长连接业务不掉线？？？解决方案//世耕通信全球办公专网

class NodeHealthMonitor:
    def __init__(self):
        self.check_interval = 30  # 秒
        
    def start_monitoring(self):
        while True:
            for node_id, node in self.nodes.items():
                # 综合健康检查
                health_score = self.comprehensive_health_check(node)
                node["health_status"] = "active" if health_score > 80 else "degraded"
                
                # 动态调整负载系数
                node["load_factor"] = self.calculate_load_factor(node)
                
            time.sleep(self.check_interval)
    
    def comprehensive_health_check(self, node):
        """综合健康检查"""
        checks = [
            self._check_latency(node),
            self._check_packet_loss(node),
            self._check_cpu_usage(node),
            self._check_bandwidth(node)
        ]
        
        return sum(checks) / len(checks)

class SmartDNSResolver:
    def resolve(self, domain, client_ip):
        """智能DNS解析"""
        # 1. 地理位置识别
        client_region = self.geoip_lookup(client_ip)
        
        # 2. 节点选择策略
        best_node = self.select_best_node_for_region(domain, client_region)
        
        # 3. 返回最优IP
        return best_node["ip_address"]
    
    def geoip_lookup(self, ip_address):
        """IP地理位置查询"""
        # 使用本地MaxMind数据库或第三方API
        response = requests.get(f"http://geoip.example.com/{ip_address}")
        return response.json()["region"]

class SessionPool:
    def __init__(self, max_size=1000, ttl=300):
        self.sessions = {}
        self.max_size = max_size
        self.ttl = ttl  # 会话存活时间（秒）
    
    def get_session(self, session_key):
        """获取会话"""
        if session_key in self.sessions:
            session = self.sessions[session_key]
            if time.time() - session["last_used"] < self.ttl:
                session["last_used"] = time.time()
                return session["connection"]
        return None
    
    def add_session(self, session_key, connection):
        """添加会话"""
        if len(self.sessions) >= self.max_size:
            self._evict_oldest()
        
        self.sessions[session_key] = {
            "connection": connection,
            "created": time.time(),
            "last_used": time.time()
        }
    
    def _evict_oldest(self):
        """淘汰最久未使用的会话"""
        oldest_key = None
        oldest_time = float('inf')
        
        for key, session in self.sessions.items():
            if session["last_used"] < oldest_time:
                oldest_time = session["last_used"]
                oldest_key = key        
        if oldest_key:
            self.sessions[oldest_key]["connection"].close()
            del self.sessions[oldest_key]

class AuditLogger:
    def log_request(self, request, response, node):
        """记录访问日志"""
        log_entry = {
            "timestamp": datetime.now().isoformat(),
            "user_id": request["user_id"],
            "source_ip": request["client_ip"],
            "target_host": request["host"],
            "target_path": request["path"],
            "method": request["method"],
            "user_agent": request["user_agent"],
            "node_id": node["id"],
            "response_status": response.status_code,
            "response_size": len(response.content),
            "processing_time": response.elapsed.total_seconds(),
            "compliance_check": "passed"
        }
        
        # 写入审计数据库
        self.db.insert("access_logs", log_entry)
        
        # 实时监控报警
        if response.status_code >= 500:
            self.alert_ops_team("backend_error", log_entry)
        
        if response.elapsed.total_seconds() > 5:
            self.alert_ops_team("slow_response", log_entry)

class ConnectionPool:
    def __init__(self):
        self.pool = {}
        self.max_pool_size = 100
        self.cleanup_interval = 60  # 秒
    
    def get_connection(self, node_id, host):
        """获取连接"""
        key = f"{node_id}_{host}"
        if key in self.pool:
            conn = self.pool[key]["connection"]
            if self._is_connection_alive(conn):
                self.pool[key]["last_used"] = time.time()
                return conn        
        # 创建新连接
        new_conn = self._create_new_connection(node_id, host)
        self._add_to_pool(key, new_conn)
        return new_conn    
    def _add_to_pool(self, key, connection):
        """添加到连接池"""
        if len(self.pool) >= self.max_pool_size:
            self._evict_oldest_connection()
        
        self.pool[key] = {
            "connection": connection,
            "created": time.time(),
            "last_used": time.time()
        }

class ComplianceEngine:
    def validate_request(self, request):
        """多层合规验证"""
        checks = [
            self._check_domain_whitelist(request["host"]),
            self._check_content_policy(request),
            self._check_user_permissions(request["user_id"], request["host"]),
            self._check_access_time(request["user_id"], request["host"]),
            self._check_data_classification(request)
        ]
        
        if all(checks):
            return True
        else:
            raise ComplianceError("请求未通过合规检查")
    
    def _check_data_classification(self, request):
        """数据分类检查"""
        if request["method"] in ["POST", "PUT"]:
            # 检查是否包含敏感数据
            sensitive_keywords = self.load_sensitive_keywords()
            content = request.get("body", "")
            
            for keyword in sensitive_keywords:
                if keyword in content:
                    # 触发额外审计
                    self.log_sensitive_data_access(
                        request["user_id"], 
                        request["host"], 
                        keyword                    )
                    return False
        
        return True