Do something when a product is published in WooCommerce

woocommerce-publish-product-action-hook.php

<?php
/**
 * @snippet       Do Something When Product is Published
 * @how-to        Watch tutorial @ https://businessbloomer.com/?p=19055
 * @sourcecode    https://businessbloomer.com/?p=543
 * @author        Rodolfo Melogli
 * @testedwith    WooCommerce 3.2.6
 */
 
function add_this_to_new_products( $new_status, $old_status, $post ) {
 
    global $post;
 
    if ( $post->post_type !== 'product' ) return;
 
    if ( 'publish' !== $new_status or 'publish' === $old_status ) return;
 
    add_post_meta( $post->ID, 'total_amount', '0', true ); // This is the action to take
 
}
 
add_action( 'transition_post_status', 'add_this_to_new_products', 10, 3 );