获取销售日期可变产品woo

Question

我想获取可变产品的计划日期销售，并尝试编码

function sales_timer_echo_product_from() {

        global $product;
if( $product->is_type('variable') ){
        $sale_price_dates   = get_post_meta($variation_id->get_date_on_sale_from(), '_sale_price_dates_from', true );
        $sale_price_dates_from  = get_post_meta($variation_id->get_date_on_sale_to(), '_sale_price_dates_to', true );
        //global $post;

        //$regular_price    = get_post_meta( $post->ID, '_sale_price_dates_to', true );
        if(!empty($sale_price_dates_from)) {

        echo '<div class="countdown-container" id="sales_timer_display_from'.$variation_id->get_date_on_sale_from().'" data-date-from="'.date("Y-m-d H:i:s",$sale_price_dates_from).'"></div>';
      }
   }
}

和

function sales_timer_echo_product_from() {

        global $product;
if( $product->is_type('variable') ){
        $sale_price_dates   = get_post_meta( $product->get_id(), '_sale_price_dates_to', true );
        $sale_price_dates_from  = get_post_meta( $product->get_id(), '_sale_price_dates_from', true );
        //global $post;

        //$regular_price    = get_post_meta( $post->ID, '_sale_price_dates_to', true );
        if(!empty($sale_price_dates_from)) {

        echo '<div class="countdown-container" id="sales_timer_display_from'.$product->get_id().'" data-date-from="'.date("Y-m-d H:i:s",$sale_price_dates_from).'">
     }
   }
}

我尝试更改此设置，但没有希望，或者我错了什么

$date_from = isset( $variation['sale_price_dates_from'] ) ? strtotime( $variation['sale_price_dates_from'] ) : get_post_meta($variation_id, '_sale_price_dates_from', true);    
$date_to   = isset( $variation['sale_price_dates_to'] ) ? strtotime( $variation['sale_price_dates_to'] ) : get_post_meta($variation_id, '_sale_price_dates_to', true);

它们不适用于可变产品，请帮助我解决此问题。