wc-log-webhook-as-order-note.php

add_action( 'woocommerce_webhook_delivery', function( $args, $response, $duration, $arg, $webhook_id ) {
	$order = wc_get_order( $arg );

    if (
        empty( $order )
        || is_wp_error( $order )
        || !is_a( $order, 'WC_Order' )
    )
        return;

    $webhook = new WC_Webhook( $webhook_id );

    if (
        empty( $webhook )
        || is_wp_error( $webhook )
        || !is_a( $webhook, 'WC_Webhook' )
    )
        return;

    if ( is_wp_error( $response ) ) {
        $errors_output = array();

        foreach ( $response->errors as $type => $errors )
            foreach ( $errors as $error )
                $errors_output[] = $type . ': ' . $error;

        $order->add_order_note(
            'Webhook <code style="font-size: 0.8em;">' . $webhook->get_name() . '</code> fired, and failed:' . "\n" .
            '<ul><li>' . implode( '</li><li>', $errors_output ) . '</li></ul>' . 
            'Connection duration: ' . $duration . 's'
        );
    } else
        $order->add_order_note(
            'Webhook <code style="font-size: 0.8em;">' . $webhook->get_name() . '</code> fired.' . "\n" .
            'Response code: ' . $response['response']['code'] . "\n" .
            'Connection duration: ' . $duration . 's'
        );
}, 10, 5 );