fix: queue monitor tasks and recover doubao dom answers

server/internal/tenant/app/desktop_task_service.go

@@ -25,7 +25,10 @@ import (
 	"github.com/geo-platform/tenant-api/internal/tenant/repository"
 )
 
-const desktopPublishMaxAttempts = 3
+const (
+	desktopPublishMaxAttempts                     = 3
+	maxConcurrentMonitorPlatformsPerDesktopClient = 2
+)
 
 var errDesktopTaskLeaseDeferred = errors.New("desktop task lease deferred")
 
@@ -520,7 +523,13 @@ func (s *DesktopTaskService) leaseNextQueuedMonitorTask(
 	}
 	hasAccountIDs := len(accountIDs) > 0
 
-	row := s.pool.QueryRow(ctx, leaseNextQueuedMonitorTaskSQL(),
+	tx, err := beginDesktopMonitorLeaseTx(ctx, s.pool, client.ID)
+	if err != nil {
+		return nil, err
+	}
+	defer tx.Rollback(ctx)
+
+	row := tx.QueryRow(ctx, leaseNextQueuedMonitorTaskSQL(),
 		client.TenantID,
 		client.WorkspaceID,
 		client.ID,
@@ -528,8 +537,16 @@ func (s *DesktopTaskService) leaseNextQueuedMonitorTask(
 		accountIDs,
 		params.AttemptID,
 		params.LeaseTokenHash,
+		maxConcurrentMonitorPlatformsPerDesktopClient,
 	)
-	return scanRepositoryDesktopTask(row)
+	task, err := scanRepositoryDesktopTask(row)
+	if err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return nil, response.ErrInternal(50088, "desktop_task_lease_failed", "failed to commit desktop monitor task lease")
+	}
+	return task, nil
 }
 
 func leaseNextQueuedMonitorTaskSQL() string {
@@ -564,6 +581,16 @@ func leaseNextQueuedMonitorTaskSQL() string {
 				  AND recent.updated_at >= now() - interval '30 seconds'
 				  AND recent.desktop_id <> dt.desktop_id
 			  )
+			  AND (
+				SELECT COUNT(DISTINCT active_platform.platform_id)
+				FROM desktop_tasks AS active_platform
+				WHERE active_platform.tenant_id = dt.tenant_id
+				  AND active_platform.workspace_id = dt.workspace_id
+				  AND active_platform.kind = 'monitor'
+				  AND active_platform.target_client_id = $3
+				  AND active_platform.status = 'in_progress'
+				  AND active_platform.desktop_id <> dt.desktop_id
+			  ) < $8::integer
 			  AND (
 				dt.target_client_id = $3
 				OR ($4::boolean AND dt.target_account_id = ANY($5::uuid[]))
@@ -658,7 +685,13 @@ func (s *DesktopTaskService) leaseQueuedDesktopTaskByID(
 	}
 	hasAccountIDs := len(accountIDs) > 0
 
-	row := s.pool.QueryRow(ctx, leaseQueuedDesktopTaskByIDSQL(),
+	tx, err := beginDesktopMonitorLeaseTx(ctx, s.pool, client.ID)
+	if err != nil {
+		return nil, err
+	}
+	defer tx.Rollback(ctx)
+
+	row := tx.QueryRow(ctx, leaseQueuedDesktopTaskByIDSQL(),
 		desktopID,
 		client.WorkspaceID,
 		client.TenantID,
@@ -668,8 +701,16 @@ func (s *DesktopTaskService) leaseQueuedDesktopTaskByID(
 		params.AttemptID,
 		params.LeaseTokenHash,
 		desktopPublishMaxAttempts,
+		maxConcurrentMonitorPlatformsPerDesktopClient,
 	)
-	return scanRepositoryDesktopTask(row)
+	task, err := scanRepositoryDesktopTask(row)
+	if err != nil {
+		return nil, err
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return nil, response.ErrInternal(50088, "desktop_task_lease_failed", "failed to commit desktop task lease")
+	}
+	return task, nil
 }
 
 func leaseQueuedDesktopTaskByIDSQL() string {
@@ -722,6 +763,19 @@ func leaseQueuedDesktopTaskByIDSQL() string {
 					  AND recent.desktop_id <> dt.desktop_id
 				)
 			  )
+			  AND (
+				dt.kind <> 'monitor'
+				OR (
+					SELECT COUNT(DISTINCT active_platform.platform_id)
+					FROM desktop_tasks AS active_platform
+					WHERE active_platform.tenant_id = dt.tenant_id
+					  AND active_platform.workspace_id = dt.workspace_id
+					  AND active_platform.kind = 'monitor'
+					  AND active_platform.target_client_id = $4
+					  AND active_platform.status = 'in_progress'
+					  AND active_platform.desktop_id <> dt.desktop_id
+				) < $10::integer
+			  )
 			  AND (
 				(
 					dt.kind = 'monitor'
@@ -753,6 +807,21 @@ func leaseQueuedDesktopTaskByIDSQL() string {
 		RETURNING ` + desktopTaskRepositoryReturningColumns
 }
 
+func beginDesktopMonitorLeaseTx(ctx context.Context, pool *pgxpool.Pool, clientID uuid.UUID) (pgx.Tx, error) {
+	if pool == nil {
+		return nil, response.ErrInternal(50088, "desktop_task_lease_failed", "desktop task pool is not available")
+	}
+	tx, err := pool.Begin(ctx)
+	if err != nil {
+		return nil, response.ErrInternal(50088, "desktop_task_lease_failed", "failed to start desktop monitor task lease")
+	}
+	if _, err := tx.Exec(ctx, `SELECT pg_advisory_xact_lock($1)`, monitorDesktopTaskClientSlotLockKey(clientID)); err != nil {
+		_ = tx.Rollback(ctx)
+		return nil, response.ErrInternal(50088, "desktop_task_lease_failed", "failed to lock desktop monitor task lease")
+	}
+	return tx, nil
+}
+
 func (s *DesktopTaskService) loadMonitorLeaseAccountIDs(ctx context.Context, client *repository.DesktopClient) ([]uuid.UUID, error) {
 	if s == nil || client == nil || s.pool == nil {
 		return nil, nil