Developing Windows Service with Autofac, Atlas and Quartz.NET

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There are many articles about implementing a scheduled job using Autofac and Quartz.NET on the Internet. However, they are not quite complete. They just provide some concepts but not actual working example. In general, this post follows Mark Jourdan's post, A quick way to create a windows service using Autofac, Quartz and Atlas. However, it actually didn't go into how to run method from resolved instances. Here in this post, I'll walkthrough how to develop a Windows Service using Autofac, Atlas and Quartz.NET with some corrections of Mark's post. The source code used for this post can be found here:

Windows Service with Autofac Atlas & Quartz.NET

Downloading NuGet Packages

In order for this application to get working, several NeGet package libraries need to be installed before starting.

Autofac: http://www.nuget.org/packages/Autofac
Atlas: http://www.nuget.org/packages/Atlas
Quartz.NET: http://www.nuget.org/packages/Quartz

NOTE: At the time of writing this post, the version of Autofac is 3.4.0 but Atlas only supports up to 3.3.1 version of Autofac. Please make sure this.

Preparing Console Application for `Atlas`

With, Atlas, a console application can easily turn into a Windows Service application. So, let's create a console application project into a solution file.

First of all, App.config needs to be setup for Atlas.

Now, have a look at the following code snippet.

internal class Program
{
    private static readonly ILog Log = LogManager.GetCurrentClassLogger();

    static void Main(string\[\] args)
    {
        try
        {
            var configuration = Host.UseAppConfig() // #1
                                    .AllowMultipleInstances()      // #2
                                    .WithRegistrations(p => p.RegisterModule(new SampleModule())); // #3
            if (args != null && args.Any())
                configuration = configuration.WithArguments(args); // #4

            Host.Start(configuration);                             // #5
        }
        catch (Exception ex)
        {
            Log.Fatal("Exception during startup.", ex);
            Console.ReadLine();
        }
    }
}

#1: Let Atlas know that SampleService is run as a Windows Service.
#2: Let Atlas allow to run multiple instances. Comment or remove this, if not necessary.
#3: Register the IoC container built with Autofac
#4: Add arguements, if provided.
#5: Start Atlas.

Both #1 and #3 are the most crucial part of the post. #1 defines the actual Windows Service to run and #3 defines IoC container for dependency injection. First comes first. Let's start with #1.

Implementing `SampleService`

SampleService must implement the IAmAHostedProcess interface to be run on top of Atlas. First of all, App.config needs CronExpression value within the <appSettings> element.

This value tells the scheduler to run the job per every 10 seconds. Now, let's implement the SampleService class for the actual Windows Service.

internal class SampleService : IAmAHostedProcess
{
    private static readonly ILog Log = LogManager.GetCurrentClassLogger();

    public IScheduler Scheduler { get; set; }           // #1

    public IJobFactory JobFactory { get; set; }         // #2

    public IJobListener JobListener { get; set; }       // #3

    public void Start()
    {
        Log.Info("Sample Windows Service starting");

        var job = JobBuilder.Create()
                            .WithIdentity("SampleJob", "SampleWindowsService")
                            .Build();                   // #4

        var trigger = TriggerBuilder.Create()
                                    .WithIdentity("SampleTrigger", "SampleWindowsService")
                                    .WithCronSchedule(ConfigurationManager.AppSettings\["CronExpression"\])   // #5
                                    .ForJob("SampleJob", "SampleWindowsService")
                                    .Build();           // #6

        this.Scheduler.JobFactory = this.JobFactory;    // #7
        this.Scheduler.ScheduleJob(job, trigger);       // #8
        this.Scheduler.ListenerManager.AddJobListener(this.JobListener);    // #9
        this.Scheduler.Start();                         // #10

        Log.Info("Sample Windows Service started");
    }

    public void Stop()
    {
        Log.Info("Sample Windows Service stopping");

        this.Scheduler.Shutdown();

        Log.Info("Sample Windows Service stopped");
    }

    public void Resume()
    {
        Log.Info("Sample Windows Service resuming");

        this.Scheduler.ResumeAll();

        Log.Info("Sample Windows Service resumed");
    }

    public void Pause()
    {
        Log.Info("Sample Windows Service pausing");

        this.Scheduler.PauseAll();

        Log.Info("Sample Windows Service paused");
    }
}

#1: IScheduler instance is injected through the IoC container.
#2: IJobFactory instance is injected through the IoC container.
#3: IJobListener instance is injected through the IoC container.
#4: Builds a SampleJob instance.
#5: Lets a trigger to run the SampleJob instance on the schedule using the cron expression.
#6: Builds a trigger instance.
#7: Let the IScheduler instance to resolve instances built through the IoC container.
#8: Schedule the SampleJob instance with the trigger built.
#9: Adds a IJobListener instance while the SampleJob is being executed.
#10: Starts the IScheduler instance.

IScheduler instance is defined in the IoC container and injected into the SampleService instance. Make sure, both IJobFactory and IJobListener instances are also injected from the IoC container. The IoC container is defined by the SampleModule instance which comes to the next section.

Implementing `SampleModule`

SampleModule works as an IoC container with Autofac. With this, all instances used in this Windows Service are registered and resolved. SampleModule inherits the Autofac.Module class.

internal class SampleModule : Module
{
    protected override void Load(ContainerBuilder builder)
    {
        this.LoadQuartz(builder);
        this.LoadServices(builder);
        this.LoadLogicLayers(builder);
    }

    private void LoadQuartz(ContainerBuilder builder)
    {
        builder.Register(c => new StdSchedulerFactory().GetScheduler())
               .As()
               .InstancePerLifetimeScope(); // #1
        builder.Register(c => new SampleJobFactory(ContainerProvider.Instance.ApplicationContainer))
               .As();          // #2
        builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly())
               .Where(p => typeof (IJob).IsAssignableFrom(p))
               .PropertiesAutowired();      // #3
        builder.Register(c => new SampleJobListener(ContainerProvider.Instance))
               .As();         // #4
    }

    private void LoadServices(ContainerBuilder builder)
    {
        builder.RegisterType()
               .As()
               .PropertiesAutowired();      // #5
    }

    private void LoadLogicLayers(ContainerBuilder builder)
    {
        builder.RegisterType()
               .As();    // #6
    }
}

#1: Registers the IScheduler instance.
#2: Registers the IJobFactory instance.
#3: Registers the IJob instance. This will resolve the SampleJob instance.
#4: Registers the IJobListener instance.
#5: Registers the IAmAHostedProcess instance. This will resolve the SampleService instance.
#6: Registers the ISampleLogicLayer instance. This will run the actual business logic.

When #5 is resolved, its properties will get IScheduler, IJobFactory and IJobListener instances injected. Let's move onto the SampleJob class to execute the real job.

Implementing `SampleJob`

The SampleJob class actually runs the business logic instance resolved from the IoC container.

internal class SampleJob : IJob
{
    private static readonly ILog Log = LogManager.GetCurrentClassLogger();

    public ISampleLogicLayer SampleLogicLayer { get; set; }

    public void Execute(IJobExecutionContext context)
    {
        Log.Info("Application executing");

        this.SampleLogicLayer.Run();

        Log.Info("Application executed");
    }
}

And the SampleJob needs the ISampleLogicLayer instance.

internal interface ISampleLogicLayer : IDisposable
{
    void Run();
}

internal class SampleLogicLayer : ISampleLogicLayer
{
    private static readonly ILog Log = LogManager.GetCurrentClassLogger();

    public void Run()
    {
        Log.Info("This has been run");
    }

    public void Dispose()
    {
    }
}

Therefore, when the SampleJob instance is executed, it calls the method Run() of the ISampleLogicLayer instance. The Run() method writes a log into the logger instance. So far, we've implemented the core logics. However, Quartz.NET needs to know whether all necessary instances are resolved or not. Let's move onto the next section to let Quartz.NET know the IoC container is ready for use.

Implementing `SampleJobFactory`

In order to let the IScheduler know all necessary instances are ready for use, an IJobFactory instance needs to be injected. Here's a code snippet for the class implementing the IJobFactory interface.

internal class SampleJobFactory : IJobFactory
{
    private readonly IContainer \_container;

    public SampleJobFactory(IContainer container)
    {
        if (container == null)
            throw new ArgumentNullException("container");

        this.\_container = container;
    }

    public IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler)
    {
        if (bundle == null)
            throw new ArgumentNullException("bundle");

        return (IJob)this.\_container.Resolve(bundle.JobDetail.JobType); // #1
    }

    public void ReturnJob(IJob job)
    {
    }
}

#1: Returns the resolved job instance. In our example, it returns the SampleJob instance resolved from the IoC container.

Let's move back to the SampleService section above. The SampleService gets this IJobFactory instance as a parameter and the IJobFactory instance is set to the ISchedule's JobFactory property. By doing so, instances that Autofac IoC container register and resolve are notified to the scheduler so that it runs the job correctly. Now, as a final section, implement SampleJobListener class.

Implementing `SampleJobListener`

SampleJobListener makes sure the job instance gets all necessary instances injected before executing the job and disposes all relevant resources after being executed.

internal class SampleJobListener : IJobListener
{
    private readonly IContainerProvider \_provider;

    private IUnitOfWorkContainer \_container;

    public SampleJobListener(IContainerProvider provider)
    {
        if (provider == null)
            throw new ArgumentNullException("provider");

        this.\_provider = provider;
        this.Name = "SampleJobListener";
    }

    public string Name { get; private set; }

    public void JobToBeExecuted(IJobExecutionContext context)
    {
        this.\_container = this.\_provider.CreateUnitOfWork();
        this.\_container.InjectUnsetProperties(context.JobInstance);
    }

    public void JobExecutionVetoed(IJobExecutionContext context)
    {
    }

    public void JobWasExecuted(IJobExecutionContext context, JobExecutionException jobException)
    {
        this.\_container.Dispose();
    }
}

As above, all the implementations have been completed. It's now time to run this. In order to debug this application on the console mode, simple put the parameter of console on the debug mode.

Make sure that App.config needs to have the logging configuration like below.

Once it's done, punch F5 key for debug. Then you'll see the result similar to the following screen:

Conclusion

Implementing a Windows Service with Autofac, Atlas and Quartz.NET is a little bit tricky, as transferring IoC container needs some extra implementation. This sample application can provide a brief overview how to use those libraries in a consolidated manner. Once you are familiar with them, your Windows Service application that needs scheduling will be a lot easier to develop.

Downloading NuGet Packages

Preparing Console Application for Atlas

Implementing SampleService

Implementing SampleModule

Implementing SampleJob

Implementing SampleJobFactory

Implementing SampleJobListener