Woocommerce: function to update all products

I have an issue with my Woocommerce products. This issue is fixed if I just update the product (edit the product and click in the Update button) with no changes at all.

I have around 2000 products in my site, then I am thinking of doing this using a function in my function.php file.

It should be something like this, I just need the line which update the product.

function update_all_products(){

    // getting all products
    $products = get_posts( $args );

    // Going through all products
    foreach ( $products as $key => $value ) {

        // the product ID
        $product_id = $value->ID;

        // update product
        update_post_meta...(NEED HELP HERE)...

   } //..end foreach
}

// fire the function
update_all_products();

Answer

Try the following, that will update your products by 200 each time to avoid problems (if you have variable products also, the post_type arg will need to be product & product_variation):

 add_action( 'woocommerce_loaded', 'update_products_by_x' );
function update_products_by_x(){
    $limit = 200;

    // getting all products
    $products_ids = get_posts( array(
        'post_type'        => 'product', // or ['product','product_variation'],
        'numberposts'      => $limit,
        'post_status'      => 'publish',
        'fields'           => 'ids',
        'meta_query'       => array( array(
            'key'     => '_sync_updated',
            'compare' => 'NOT EXISTS',
        ) )
    ) );

    // Loop through product Ids
    foreach ( $products_ids as $product_id ) {

        // Get the WC_Product object
        $product = wc_get_product($product_id);

        // Mark product as updated
        $product->update_meta_data( '_sync_updated', true );

        $product->save();
    }
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.

Each time you will browse a page of your site the function will be triggered. processing products by 200 is just more secure and will avoid a timeout or errors.

You can increase that number to 500 for example, setting the $limit to 500