0 0 1 */4 * Cron Schedule Reference | CronBase

#!/usr/bin/env bash
set -euo pipefail

# Production-grade script to safely install the triannual cron job
CRON_JOB="0 0 1 */4 * /usr/local/bin/triannual-cleanup.sh >> /var/log/cleanup.log 2>&1"

# Verify the target script exists before scheduling
if [ ! -f /usr/local/bin/triannual-cleanup.sh ]; then
    echo "Warning: Target script /usr/local/bin/triannual-cleanup.sh does not exist yet."
fi

# Check if the cron job already exists to prevent duplicate entries
if crontab -l 2>/dev/null | grep -Fq "/usr/local/bin/triannual-cleanup.sh"; then
    echo "Cron job already exists. Skipping deployment."
else
    (crontab -l 2>/dev/null; echo "$CRON_JOB") | crontab -
    echo "Successfully scheduled triannual cleanup job in crontab."
fi

const cron = require('node-cron');
const winston = require('winston'); // Production logger

const logger = winston.createLogger({
    level: 'info',
    transports: [new winston.transports.Console()]
});

// Expression: 0 0 1 */4 * (At midnight on day 1 of every 4th month)
const CRON_SCHEDULE = '0 0 1 */4 *';

try {
    const task = cron.schedule(CRON_SCHEDULE, async () => {
        const startTime = Date.now();
        logger.info('Starting triannual database archiving task...');
        try {
            // Perform heavy historical database archiving and index management
            await runArchivingPipeline();
            const duration = Date.now() - startTime;
            logger.info(`Archiving completed successfully in ${duration}ms`);
        } catch (error) {
            logger.error('Critical failure in triannual archiving job:', error);
            // Route to your incident response system (e.g., PagerDuty, Opsgenie)
            await alertOpsTeam(error);
        }
    }, {
        scheduled: true,
        timezone: "UTC" // Enforce UTC to avoid daylight saving shifts
    });
    task.start();
    logger.info('Triannual scheduler initialized successfully.');
} catch (initError) {
    logger.error('Failed to initialize triannual cron task:', initError);
    process.exit(1);
}

async function runArchivingPipeline() { /* Real business logic goes here */ }
async function alertOpsTeam(err) { /* Notification integration */ }

import logging
import sys
from datetime import datetime
from apscheduler.schedulers.blocking import BlockingScheduler
from apscheduler.triggers.cron import CronTrigger

logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
logger = logging.getLogger('TriannualScheduler')

def execute_triannual_audit():
    logger.info("Initiating triannual audit and compliance report generation...")
    try:
        # Place long-running audit logic here
        logger.info("Triannual audit completed successfully.")
    except Exception as e:
        logger.error(f"Fatal error during triannual execution: {str(e)}", exc_info=True)
        # Route to your alerting service
        sys.exit(1)

if __name__ == "__main__":
    scheduler = BlockingScheduler()
    # 0 0 1 */4 * -> equivalent to months 1, 5, 9
    trigger = CronTrigger(
        month='1,5,9',
        day=1,
        hour=0,
        minute=0,
        timezone='UTC'
    )
    scheduler.add_job(execute_triannual_audit, trigger=trigger, id='triannual_audit_job')
    logger.info("Scheduler started. Monitoring triannual job...")
    try:
        scheduler.start()
    except (KeyboardInterrupt, SystemExit):
        logger.info("Scheduler stopped cleanly.")

package main

import (
	"log"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/robfig/cron/v3"
)

func runTriannualReport() {
	log.Println("Starting triannual financial consolidation...")
	// Perform actual business logic here
	log.Println("Triannual financial consolidation completed.")
}

func main() {
	// Load UTC location to avoid timezone offsets on production servers
	utc, err := time.LoadLocation("UTC")
	if err != nil {
		log.Fatalf("Failed to load UTC timezone: %v", err)
	}

	c := cron.New(cron.WithLocation(utc))
	
	// Standard cron expression: 0 0 1 */4 *
	cronSpec := "0 0 1 */4 *"
	
	_, err = c.AddFunc(cronSpec, func() {
		defer func() {
			if r := recover(); r != nil {
				log.Printf("Recovered from panic in triannual job: %v", r)
			}
		}()
		runTriannualReport()
	})
	if err != nil {
		log.Fatalf("Error scheduling triannual job: %v", err)
	}

	c.Start()
	log.Println("Triannual scheduler started successfully under UTC.")

	// Handle clean shutdown
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
	<-sigChan

	log.Println("Shutting down scheduler...")
	c.Stop()
}

package com.example.scheduler;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

@Component
public class TriannualMaintenanceScheduler {

    private static final Logger logger = LoggerFactory.getLogger(TriannualMaintenanceScheduler.class);

    // Spring cron: "second minute hour day-of-month month day-of-week"
    // We enforce UTC to ensure consistent behavior across distributed cloud nodes
    @Scheduled(cron = "0 0 0 1 */4 *", zone = "UTC")
    public void executeTriannualTask() {
        logger.info("Starting triannual system-wide maintenance and data purging...");
        try {
            processPurgePipeline();
            logger.info("Triannual maintenance completed successfully.");
        } catch (Exception e) {
            logger.error("Critical failure during triannual maintenance execution", e);
            // Standard practice: trigger external alerts or dead-man switch notifications
        }
    }

    private void processPurgePipeline() {
        // Production-grade logic for purging old partition indexes
    }
}

apiVersion: batch/v1
kind: CronJob
metadata:
  name: triannual-data-archiver
  namespace: production
  labels: 
    app: triannual-archiver
    tier: backend
spec:
  schedule: "0 0 1 */4 *"
  concurrencyPolicy: Forbid
  successfulJobsHistoryLimit: 3
  failedJobsHistoryLimit: 5
  startingDeadlineSeconds: 14400 # 4 hours to recover from cluster downtime
  jobTemplate:
    spec:
      template:
        metadata:
          labels:
            app: triannual-archiver
        spec:
          restartPolicy: OnFailure
          containers:
          - name: archiver
            image: registry.internal.net/data/archiver:v2.4.1
            env:
            - name: TZ
              value: "UTC"
            resources:
              limits:
                cpu: "1000m"
                memory: "2Gi"
              requests:
                cpu: "250m"
                memory: "512Mi"