fix: 接线 Prometheus 指标到连接与投递事件

internal/app/message/ack.go

@@ -17,6 +17,8 @@ func (a *App) Ack(ctx context.Context, endpointID string, req *protocol.Ack) (Ac
 	nowMs := a.now().UnixMilli()
 	var out AckResult
 	var seq int64
+	var ackLatencySec float64
+	var observeAck bool
 	err := a.db.Queue.Do(ctx, func(tx *sql.Tx) error {
 		err := tx.QueryRow(`SELECT seq FROM messages WHERE sender_id = ? AND id = ?`, req.From, req.ID).Scan(&seq)
 		if err == sql.ErrNoRows {
@@ -25,6 +27,10 @@ func (a *App) Ack(ctx context.Context, endpointID string, req *protocol.Ack) (Ac
 		if err != nil {
 			return err
 		}
+		var pushedAt sql.NullInt64
+		_ = tx.QueryRow(`
+SELECT pushed_at FROM deliveries
+WHERE seq = ? AND endpoint_id = ? AND state = 'pending'`, seq, endpointID).Scan(&pushedAt)
 		res, err := tx.Exec(`
 UPDATE deliveries SET state = ?, reason = '', pushed_conn = NULL, updated_at = ?
 WHERE seq = ? AND endpoint_id = ? AND state = 'pending'`,
@@ -35,6 +41,10 @@ WHERE seq = ? AND endpoint_id = ? AND state = 'pending'`,
 		aff, _ := res.RowsAffected()
 		if aff > 0 {
 			out.Result = DeliveryAccepted
+			if pushedAt.Valid && pushedAt.Int64 > 0 && nowMs >= pushedAt.Int64 {
+				ackLatencySec = float64(nowMs-pushedAt.Int64) / 1000.0
+				observeAck = true
+			}
 			if e := insertReceiptTx(tx, req.From, seq, endpointID, DeliveryAccepted, "", nowMs); e != nil {
 				return e
 			}
@@ -55,6 +65,9 @@ SELECT state FROM deliveries WHERE seq = ? AND endpoint_id = ?`, seq, endpointID
 	if err != nil {
 		return out, err
 	}
+	if observeAck && a.met != nil {
+		a.met.AckSeconds.Observe(ackLatencySec)
+	}
 	if out.Result == DeliveryAccepted {
 		a.releaseLarge(seq, endpointID)
 	}