fix: prevent reconnect after pool close

db/clickhouse.go

@@ -2,6 +2,7 @@ package db
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log"
 	"net"
@@ -22,8 +23,11 @@ type Pool struct {
 	mu                sync.RWMutex
 	conn              clickhouse.Conn
 	healthy           bool
+	closed            bool
 }
 
+var errPoolClosed = errors.New("db pool is closed")
+
 // NewPool 创建 Pool。即使首次连接失败也返回非 nil 实例，后台会持续重试。
 func NewPool(ctx context.Context, dsn string, reconnectInterval time.Duration) *Pool {
 	p := &Pool{dsn: dsn, reconnectInterval: reconnectInterval}
@@ -35,6 +39,13 @@ func NewPool(ctx context.Context, dsn string, reconnectInterval time.Duration) *
 }
 
 func (p *Pool) connect(ctx context.Context) error {
+	p.mu.RLock()
+	closed := p.closed
+	p.mu.RUnlock()
+	if closed {
+		return errPoolClosed
+	}
+
 	cctx, cancel := context.WithTimeout(ctx, 5*time.Second)
 	defer cancel()
 	opts, err := ClickHouseOptions(p.dsn)
@@ -62,6 +73,11 @@ func (p *Pool) connect(ctx context.Context) error {
 		return err
 	}
 	p.mu.Lock()
+	if p.closed {
+		p.mu.Unlock()
+		_ = conn.Close()
+		return errPoolClosed
+	}
 	if p.conn != nil {
 		_ = p.conn.Close()
 	}
@@ -217,6 +233,7 @@ func (p *Pool) Get() clickhouse.Conn {
 // Close starts closing the underlying connection and waits within ctx.
 func (p *Pool) Close(ctx context.Context) error {
 	p.mu.Lock()
+	p.closed = true
 	conn := p.conn
 	p.conn = nil
 	p.healthy = false