An example plugin for minutely tasks using WP-Cron

wp-cron-minutely.php

<?php
/**
 * WP-Cron Minutely
 *
 * @package     WPCronMinutely
 * @author      Bernhard Kau
 * @license     GPLv3
 *
 * @wordpress-plugin
 * Plugin Name: WP-Cron Minutely
 * Plugin URI:  https://kau-boys.com
 * Description: An example plugin for minutely tasks using WP-Cron
 * Version:     1.0.0
 * Author:      Bernhard Kau
 * Author URI:  https://kau-boys.com
 * License:     GPLv3
 * License URI: http://www.gnu.org/licenses/gpl-3.0
 */

add_action( 'init', 'wp_cron_minutely_init' );

register_deactivation_hook( __FILE__, 'wp_cron_minutely_deactivate' );

/**
 * Add the schedules interval, cron hook and schedules the events.
 */
function wp_cron_minutely_init() {

	add_filter( 'cron_schedules', 'wp_cron_minutely_add_cron_schedules' );

	add_action( 'wp_cron_minutely_cron_hook', 'wp_cron_minutely_cron_exec' );

	if ( ! wp_next_scheduled( 'wp_cron_minutely_cron_hook' ) ) {
		wp_schedule_event( time(), '1min', 'wp_cron_minutely_cron_hook' );
	}
}

/**
 * Add a minutely interval for wp_cron.
 *
 * @param array $schedules The schedules intervals array.
 *
 * @return array
 */
function wp_cron_minutely_add_cron_schedules( $schedules ) {
	if ( ! isset( $schedules['1min'] ) ) {
		$schedules['1min'] = array(
			'interval' => 60,
			'display'  => esc_html__( 'Every minute', 'wp-cron-minutely' ),
		);
	}

	return $schedules;
}

/**
 * Increments an option by 1 every time the hook was called
 */
function wp_cron_minutely_cron_exec() {

	if ( $calls = get_option( 'wp_cron_minutely_cron_hook_calls' ) ) {
		update_option( 'wp_cron_minutely_cron_hook_calls', $calls + 1 );
	} else {
		add_option( 'wp_cron_minutely_cron_hook_calls', 1 );
	}
}

/**
 * Remove the scheduled task on plugin deactivation.
 */
function wp_cron_minutely_deactivate() {
	$timestamp = wp_next_scheduled( 'wp_cron_minutely_cron_hook' );
	wp_unschedule_event( $timestamp, 'wp_cron_minutely_cron_hook' );
	delete_option( 'wp_cron_minutely_cron_hook_calls' );
}