feat: 实现内存版 SessionManager（TTL 30 分钟，历史上限 20 条）
This commit is contained in:
275
backend/internal/session/memory.go
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275
backend/internal/session/memory.go
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@@ -0,0 +1,275 @@
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package session
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import (
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"context"
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"sync"
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"time"
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"github.com/google/uuid"
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"github.com/hhs/camtalk/internal/logger"
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"github.com/hhs/camtalk/internal/models"
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)
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const (
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defaultTTL = 30 * time.Minute
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defaultHistorySize = 20
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)
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// sessionEntry 内部会话条目。
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type sessionEntry struct {
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session models.Session
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history []models.Message
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activeReqID string
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lastActive time.Time
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}
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// MemoryManager 基于内存的 SessionManager 实现。
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// 适用于 MVP 和无 Redis 的开发环境。
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type MemoryManager struct {
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mu sync.RWMutex
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sessions map[string]*sessionEntry
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ttl time.Duration
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maxHistory int
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stopCleaner chan struct{}
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}
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// NewMemoryManager 创建内存版 SessionManager。
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// ttl 为会话过期时间，maxHistory 为对话历史上限（0 表示使用默认值 20）。
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func NewMemoryManager(ttl time.Duration, maxHistory int) *MemoryManager {
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if ttl <= 0 {
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ttl = defaultTTL
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}
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if maxHistory <= 0 {
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maxHistory = defaultHistorySize
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}
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m := &MemoryManager{
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sessions: make(map[string]*sessionEntry),
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ttl: ttl,
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maxHistory: maxHistory,
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stopCleaner: make(chan struct{}),
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}
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// 启动后台清理 goroutine，每分钟清除过期会话。
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go m.cleanLoop()
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return m
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}
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// cleanLoop 后台定期清理过期会话。
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func (m *MemoryManager) cleanLoop() {
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ticker := time.NewTicker(1 * time.Minute)
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defer ticker.Stop()
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for {
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select {
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case <-ticker.C:
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m.cleanExpired()
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case <-m.stopCleaner:
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return
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}
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}
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}
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// cleanExpired 清除所有过期会话。
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func (m *MemoryManager) cleanExpired() {
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m.mu.Lock()
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defer m.mu.Unlock()
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now := time.Now()
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for id, entry := range m.sessions {
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if now.Sub(entry.lastActive) > m.ttl {
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delete(m.sessions, id)
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logger.Log.Debugw("session expired (cleaner)", "session", id)
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}
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}
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}
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// Stop 停止后台清理 goroutine。应用退出前调用。
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func (m *MemoryManager) Stop() {
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close(m.stopCleaner)
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}
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// isExpired 检查会话是否过期（调用方需持锁或在已知 entry 存在时调用）。
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func (m *MemoryManager) isExpired(entry *sessionEntry) bool {
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return time.Since(entry.lastActive) > m.ttl
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}
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// Create 创建新会话。
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func (m *MemoryManager) Create(_ context.Context, config models.SessionConfig) (string, error) {
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m.mu.Lock()
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defer m.mu.Unlock()
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id := uuid.New().String()
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now := time.Now()
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m.sessions[id] = &sessionEntry{
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session: models.Session{
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ID: id,
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CreatedAt: now,
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Config: config,
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},
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history: make([]models.Message, 0),
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lastActive: now,
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}
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logger.Log.Debugw("session created", "session", id)
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return id, nil
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}
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// Get 获取会话。
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func (m *MemoryManager) Get(_ context.Context, sessionID string) (*models.Session, error) {
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m.mu.RLock()
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defer m.mu.RUnlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return nil, ErrSessionNotFound
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}
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sess := entry.session // 复制一份返回
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return &sess, nil
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}
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// UpdateConfig 更新会话配置。
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func (m *MemoryManager) UpdateConfig(_ context.Context, sessionID string, patch models.SessionConfigPatch) error {
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m.mu.Lock()
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defer m.mu.Unlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return ErrSessionNotFound
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}
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patch.Apply(&entry.session.Config)
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entry.lastActive = time.Now()
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logger.Log.Debugw("session config updated", "session", sessionID)
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return nil
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}
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// GetHistory 获取最近 N 轮对话历史。
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func (m *MemoryManager) GetHistory(_ context.Context, sessionID string, limit int) ([]models.Message, error) {
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m.mu.RLock()
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defer m.mu.RUnlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return nil, ErrSessionNotFound
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}
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if limit <= 0 || limit > len(entry.history) {
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limit = len(entry.history)
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}
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// 返回最近 limit 条的副本
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result := make([]models.Message, limit)
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copy(result, entry.history[len(entry.history)-limit:])
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return result, nil
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}
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// AppendMessage 追加一条对话消息，同时刷新 TTL。
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func (m *MemoryManager) AppendMessage(_ context.Context, sessionID string, msg models.Message) error {
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m.mu.Lock()
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defer m.mu.Unlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return ErrSessionNotFound
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}
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entry.history = append(entry.history, msg)
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// 超过上限时裁剪，保留最新的 maxHistory 条
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if len(entry.history) > m.maxHistory {
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entry.history = entry.history[len(entry.history)-m.maxHistory:]
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}
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entry.lastActive = time.Now()
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return nil
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}
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// SetActiveRequest 标记当前正在处理的请求 ID。
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func (m *MemoryManager) SetActiveRequest(_ context.Context, sessionID string, requestID string) error {
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m.mu.Lock()
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defer m.mu.Unlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return ErrSessionNotFound
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}
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entry.activeReqID = requestID
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entry.lastActive = time.Now()
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return nil
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}
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// GetActiveRequestID 获取当前活跃请求 ID。
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func (m *MemoryManager) GetActiveRequestID(_ context.Context, sessionID string) (string, error) {
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m.mu.RLock()
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defer m.mu.RUnlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return "", ErrSessionNotFound
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}
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return entry.activeReqID, nil
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}
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// ClearActiveRequest 清除活跃请求标记。
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func (m *MemoryManager) ClearActiveRequest(_ context.Context, sessionID string) error {
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m.mu.Lock()
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defer m.mu.Unlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return ErrSessionNotFound
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}
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entry.activeReqID = ""
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entry.lastActive = time.Now()
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return nil
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}
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// Touch 刷新 TTL。
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func (m *MemoryManager) Touch(_ context.Context, sessionID string) error {
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m.mu.Lock()
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defer m.mu.Unlock()
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entry, ok := m.sessions[sessionID]
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if !ok || m.isExpired(entry) {
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return ErrSessionNotFound
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}
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entry.lastActive = time.Now()
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return nil
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}
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// Destroy 显式销毁会话。
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func (m *MemoryManager) Destroy(_ context.Context, sessionID string) error {
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m.mu.Lock()
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defer m.mu.Unlock()
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if _, ok := m.sessions[sessionID]; !ok {
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return ErrSessionNotFound
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}
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delete(m.sessions, sessionID)
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logger.Log.Debugw("session destroyed", "session", sessionID)
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return nil
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}
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// ActiveCount 返回当前活跃会话数。
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func (m *MemoryManager) ActiveCount() int {
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m.mu.RLock()
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defer m.mu.RUnlock()
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now := time.Now()
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count := 0
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for _, entry := range m.sessions {
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if now.Sub(entry.lastActive) <= m.ttl {
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count++
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}
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}
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return count
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}
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