⏰ Cron Task Scheduling

Many applications require periodic background tasks—such as clearing expired sessions every night at midnight, recalculating analytics hourly, or polling external feeds every 5 minutes.

ferrox-schedule provides cron-based task scheduling for background worker processes.

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1. Defining Cron Tasks

ferrox-schedule allows registering async closures scheduled with standard 5-field cron syntax:

use std::time::Duration;
use tokio::time::interval;

pub async fn schedule_daily_cleanup() {
    tokio::spawn(async {
        // Runs periodic cleanup job
        let mut timer = interval(Duration::from_secs(86400)); // Every 24 hours
        loop {
            timer.tick().await;
            println!("🧹 Running scheduled daily database cleanup...");
            // Execute cleanup logic
        }
    });
}

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2. Standard Cron Expression Syntax

Expression	Execution Schedule
*/5 * * * *	Every 5 minutes
0 * * * *	Every hour on the hour
0 0 * * *	Daily at midnight
0 0 * * 0	Every Sunday at midnight

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3. Distributed Task Locking

[!WARNING] When running multiple container replicas of your Ferrox app in Kubernetes, simple local cron timers will fire on every replica simultaneously. Combine ferrox-schedule with ferrox-sync distributed locks so only one replica executes the periodic task per interval.