sia.hackernoon.com

As a developer, you probably have tasks you’d like to automate — things like sending emails, generating reports, or cleaning up data on a schedule.

So, how do you make that happen?

That’s where services come in. They’re a great way to handle automation efficiently and reliably.

Let’s break down how you can set this up using services.

Introduction

Quartz is a popular open-source tool for scheduling and automation.

At the heart of it is the Quartz Trigger, a core component of the Quartz Scheduler, a powerful job scheduling library available in both C# and Java.

Official Documentation: https://www.quartz-scheduler.org/documentation/

What is a trigger?

A Trigger defines when and how often a job should run.
Think of it as theschedule attached to a job.

When you schedule a job in Quartz, you provide:

A Job (what to do)
A Trigger (when to do it)

Types of Quartz Triggers

Simple Trigger

Runs a job a specific number of times or at fixed intervals.
Example: run every 10 seconds, repeat 5 times.

Cron Trigger

Uses a Cron expression (like in Unix/Linux Cronjobs) for more complex schedules.
Example: run every day at 2:00 AM.

What is a Cron expression?

A Cron Expression is a string with 6 or 7 fields that defines a schedule, specifying exactly whena job should run (down to seconds).
It’s like acompact language for time-based scheduling.

Detailed expression: you can read it in their official documents.

The requirement is to read the file every 30 seconds.

Let’s implement a Cron trigger in .NET 8.

Project Settings

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <RootNamespace>CronImplementation</RootNamespace>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Quartz" Version="3.15.1" />
    <PackageReference Include="Quartz.Plugins" Version="3.15.1" />
  </ItemGroup>

	<ItemGroup>
		<Content Include="jobs.xml" CopyToOutputDirectory="Always" />
	</ItemGroup>
</Project>

Program

using Quartz;
using Quartz.Impl;
using Quartz.Xml;
using Quartz.Simpl;  // <-- needed for SimpleTypeLoadHelper

namespace CronImplementation
{
    class Program
    {
        static async Task Main(string[] args)
        {
            //Create a scheduler
            ISchedulerFactory factory = new StdSchedulerFactory();
            IScheduler scheduler = await factory.GetScheduler();

            //Create a type load helper (required by the new API)
            var typeLoadHelper = new SimpleTypeLoadHelper();
            typeLoadHelper.Initialize();

            //Use the new XMLSchedulingDataProcessor constructor
            var xmlProcessor = new XMLSchedulingDataProcessor(typeLoadHelper);

            //Ensure file path is an absolute
            string xmlPath = Path.Combine(AppContext.BaseDirectory, "jobs.xml");
            xmlProcessor.ProcessFileAndScheduleJobs(xmlPath, scheduler);

            Console.WriteLine(File.Exists(xmlPath));

            //Start the scheduler
            await scheduler.Start();

            Console.WriteLine("Quartz Scheduler started using XML configuration. Press any key to stop...");
            Console.ReadKey();

            await scheduler.Shutdown();
            Console.WriteLine("Scheduler stopped.");
        }
    }
}

File Reading Job

using Quartz;
 
namespace CronImplementation
{
    public class FileReadingJob : IJob
    {
        public Task Execute(IJobExecutionContext context)
        {
            string filePath = Path.Combine(AppContext.BaseDirectory, "file.txt");

            if (!File.Exists(filePath))
            {
                Console.WriteLine($"File not found: {filePath}");
                return Task.CompletedTask;
            }

            //Read all lines
            string[] lines = File.ReadAllLines(filePath);

            foreach (var line in lines)
            {
                Console.WriteLine(line);
            }
            Console.WriteLine($"FileReadingJob executed at: {DateTime.Now}");
            return Task.CompletedTask;
        }
    }
}

Jobs.xml

<?xml version="1.0" encoding="UTF-8"?>
<job-scheduling-data xmlns="http://quartznet.sourceforge.net/JobSchedulingData"
                     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                     version="2.0">

	<!-- List of scheduled jobs -->
	<schedule>

		<!-- Job definition -->
		<job>
			<name>FileReadingJob</name>
			<group>group1</group>
			<description>Job that reads content from file</description>
			<job-type>CronImplementation.FileReadingJob, CronImplementation</job-type>
			<!-- Namespace.ClassName, Assembly -->
			<durable>true</durable>
			<recover>false</recover>
		</job>

		<!-- Trigger definition (Cron-based) -->
		<trigger>
			<cron>
				<name>FileReadingJobTrigger</name>
				<group>group1</group>
				<job-name>FileReadingJob</job-name>
				<job-group>group1</job-group>
				<cron-expression>0/10 * * * * ?</cron-expression>
				<!-- Runs every 10 seconds -->
			</cron>
		</trigger>

	</schedule>
</job-scheduling-data>

File.txt

“This is the console app. This project explains the implementation of the Cron trigger in NET 8.”

Output

Summary

The Quartz trigger is platform-independent, meaning you can deploy your apps on both Windows and Linux servers without any issues.

Another great feature is that it lets you assign different trigger schedules to multiple jobs, giving you more flexibility in how tasks are executed.

You can also update or delete triggers by simply editing the XML file—no need to change the code. Just keep in mind that the service needs to be restarted for the changes to take effect.

Automate Tasks in .NET 8 Using Quartz and Cron Triggers