Background Server

The requirement was to have an engine to handle background jobs for tasks like (send notifications, calculate monthly bills..etc) also serve very basic workflow scenarios.

Solution

Use Hangfire + Topshelf to create a windows service to serve as the background server. Topshelf can be replaced with docker + orchestration.

How to use

BackgroundServer.Abstractions project should be referenced in an application (use case) level/layer and used as follows:

1. Fire and Forget jobs:

Use IFireAndForgetJobScheduler to run tasks in the background instantly or with a delay

var jobId = _fireAndForgetJobScheduler.EnqueueJob<SomeType>(x=>x.SomeMethod)

Also run method after a fire and forget job ends instantly or with a delay

_fireAndForgetJobScheduler.ContinueWith<SomeType>(jobId, x=> x.SomeOtherMethod)

2. Self Starting jobs:

For scenarios in which it is need to run some tasks upon the start of the Background Server

3. Recurring jobs Create an interface that implements IRecurringJob then implement that interface and provide the cron expression (preferably in the constructor) as follows

    public interface IHelloWorldRecurringJob: IRecurringJob
    {
    }

   public class HelloWorldRecurringJob : IHelloWorldRecurringJob
   {
       public string CronExpression { get; private set; }
       public HelloWorldRecurringJob()
       {
           UpdateCronExpression(Cron.Minutely());
       }

       public Task Execute()
       {
           Console.WriteLine("Hello World");
           return Task.FromResult(0);
       }

       public void UpdateCronExpression(string expression)
       {
           //Validation here
           CronExpression = expression;
       }
   }

Then there are to options to register this job

1. Using IRecurringJobScheduler.Register Method
2. Setting initializeRecurringJobs to true in IBackgroundServerManager.Start

How to run

1. Console Application

Just run the solution or start BackgroundServer.Client.ConsoleApplication.exe

2. Windows Service

• Publish the application as self-contained app

• Open as CMD administrator in the path of the deployment files

• Run dotnet BackgroundServer.Client.ConsoleApplication.dll install

• Run dotnet BackgroundServer.Client.ConsoleApplication.dll start

Stop the service :

Run dotnet BackgroundServer.Client.ConsoleApplication.dll stop

Uninstall the service:

Run Run dotnet BackgroundServer.Client.ConsoleApplication.dll uninstall

Stop the service :
Run `dotnet BackgroundServer.Client.ConsoleApplication.dll stop`

Uninstall the service:
Run `Run dotnet BackgroundServer.Client.ConsoleApplication.dll uninstall`

3. Docker Container

>docker-compose build

>docker-compose up