181 lines
3.2 KiB
Go
181 lines
3.2 KiB
Go
package db
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import (
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"crypto/rand"
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"database/sql"
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"encoding/hex"
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"fmt"
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"sync"
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"time"
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"github.com/redis/go-redis/v9"
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)
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const sessionTTL = 45 * time.Minute
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const maxSessions = 64
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type Session struct {
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ID string
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Conn ConnReq
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mu sync.Mutex
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sqlPool map[string]*sql.DB
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redisCli *redis.Client
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tunnel *SSHTunnel
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LastUsed time.Time
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}
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var (
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sessionsMu sync.Mutex
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sessions = map[string]*Session{}
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)
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func init() {
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go func() {
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t := time.NewTicker(2 * time.Minute)
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defer t.Stop()
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for range t.C {
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expireSessions()
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}
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}()
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}
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func newSessionID() string {
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var b [16]byte
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if _, err := rand.Read(b[:]); err != nil {
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return fmt.Sprintf("%d", time.Now().UnixNano())
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}
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return hex.EncodeToString(b[:])
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}
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func OpenSession(c ConnReq) (string, error) {
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c.SQL = ""
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c.Table = ""
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c.Key = ""
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c.Pattern = ""
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c.SessionID = ""
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dial, tun, err := ApplySSHTunnel(c)
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if err != nil {
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return "", err
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}
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if err := testDial(dial); err != nil {
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if tun != nil {
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tun.Close()
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}
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return "", fmt.Errorf("数据库: %w", err)
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}
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sessionsMu.Lock()
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if len(sessions) >= maxSessions {
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sessionsMu.Unlock()
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if tun != nil {
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tun.Close()
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}
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return "", fmt.Errorf("连接会话已满，请关闭不用的连接后重试")
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}
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id := newSessionID()
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// Persist dialed endpoints (127.0.0.1:local) so later ops reuse the tunnel.
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stored := dial
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stored.SSHEnabled = false
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s := &Session{
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ID: id,
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Conn: stored,
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sqlPool: map[string]*sql.DB{},
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tunnel: tun,
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LastUsed: time.Now(),
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}
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sessions[id] = s
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sessionsMu.Unlock()
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return id, nil
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}
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func GetSession(id string) (*Session, error) {
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if id == "" {
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return nil, fmt.Errorf("缺少 sessionId")
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}
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sessionsMu.Lock()
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s, ok := sessions[id]
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sessionsMu.Unlock()
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if !ok {
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return nil, fmt.Errorf("会话已失效，请重新连接")
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}
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s.mu.Lock()
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s.LastUsed = time.Now()
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s.mu.Unlock()
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return s, nil
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}
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func CloseSession(id string) {
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sessionsMu.Lock()
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s, ok := sessions[id]
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if ok {
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delete(sessions, id)
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}
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sessionsMu.Unlock()
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if ok {
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s.closeAll()
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}
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}
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func expireSessions() {
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cutoff := time.Now().Add(-sessionTTL)
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sessionsMu.Lock()
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var dead []*Session
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for id, s := range sessions {
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s.mu.Lock()
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stale := s.LastUsed.Before(cutoff)
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s.mu.Unlock()
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if stale {
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dead = append(dead, s)
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delete(sessions, id)
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}
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}
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sessionsMu.Unlock()
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for _, s := range dead {
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s.closeAll()
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}
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}
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func (s *Session) closeAll() {
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s.mu.Lock()
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defer s.mu.Unlock()
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for k, dbh := range s.sqlPool {
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_ = dbh.Close()
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delete(s.sqlPool, k)
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}
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if s.redisCli != nil {
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_ = s.redisCli.Close()
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s.redisCli = nil
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}
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if s.tunnel != nil {
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s.tunnel.Close()
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s.tunnel = nil
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}
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}
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func (s *Session) ConnFor(req ConnReq) ConnReq {
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c := s.Conn
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// SQLite 的 database 是文件路径，对象树里的 "main" 不能覆盖它
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if req.Database != "" && driverKey(c.Driver) != "sqlite" {
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c.Database = req.Database
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}
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c.SQL = req.SQL
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c.Table = req.Table
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c.Key = req.Key
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c.Pattern = req.Pattern
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c.Limit = req.Limit
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c.SessionID = s.ID
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return c
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}
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func ResolveConn(req ConnReq) (ConnReq, error) {
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if req.SessionID == "" {
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return req, nil
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}
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s, err := GetSession(req.SessionID)
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if err != nil {
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return req, err
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}
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return s.ConnFor(req), nil
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}
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