EverTask.Abstractions 1.0.4-beta

Overview

EverTask is a .NET library for executing background tasks in ASP.NET Core applications. It is designed to be simple and focuses on task persistence, ensuring that pending tasks resume upon application restart.

This project is in its initial stages, more detailed documentation will be provided in the future.

Features

Efficient Task Processing

EverTask employs a non-polling approach for task management, utilizing the .NET's System.Threading.Channels to create a BoundedQueue. This queue efficiently manages task execution without the need for constant database polling. Upon application restart after a stop, any unprocessed tasks are retrieved from the database in bulk and re-queued in the channel's queue for execution by the background service. This design ensures a seamless and efficient task processing cycle, even across application restarts.

Implementation Example

public record SampleTaskRequest(string TestProperty) : IEverTask;

public class SampleTaskRequestHanlder : EverTaskHandler<SampleTaskRequest>
{
    private readonly ILogger<SampleTaskRequestHanlder> _logger;

    public SampleTaskRequestHanlder(ILogger<SampleTaskRequestHanlder> logger)
    {
        _logger = logger;
    }
    public override Task Handle(SampleTaskRequest backgroundTask, CancellationToken cancellationToken)
    {
        _logger.LogInformation(backgroundTask.TestProperty);
        return Task.CompletedTask;
    }

    // Optional Overrides
    public override ValueTask Completed()
    {
        return base.Completed();
    }

    public override ValueTask OnError(Exception? exception, string? message)
    {
        return base.OnError(exception, message);
    }
}

Task Dispatch

To dispatch a task, obtain an instance of ITaskDispatcher. This can be done using Dependency Injection:

// Retrieving ITaskDispatcher via method injection
var _dispatcher = serviceProvider.GetService<ITaskDispatcher>();

// Alternatively, ITaskDispatcher can be injected directly into the constructor of your class
_dispatcher.Dispatch(new SampleTaskRequest("Hello World"));

Basic Configuration

builder.Services.AddEverTask(opt =>
{
    opt.SetChannelOptions(50)
       .SetThrowIfUnableToPersist(true)
       .RegisterTasksFromAssembly(typeof(Program).Assembly);
})
.AddMemoryStorage();

Advanced Configuration

builder.Services.AddEverTask(opt =>
{
    opt.SetChannelOptions(settingsManager.Settings.Properties.BackgroundQueueCapacity)
       .SetThrowIfUnableToPersist(true)
       .RegisterTasksFromAssembly(typeof(AppSettings).Assembly);
})
.AddSqlServerStorage(configuration.GetConnectionString("QueueWorkerSqlStorage")!,
    opt =>
    {
        opt.SchemaName          = "EverTask";
        opt.AutoApplyMigrations = true;
    })
.AddSerilog(opt => opt.ReadFrom.Configuration(configuration, new ConfigurationReaderOptions { SectionName = "EverTaskSerilog" }));

Service Configuration Properties

EverTaskServiceConfiguration provides various options for configuring the EverTask service. Here's a summary of its properties and their intended functionalities:

ChannelOptions

• Type: BoundedChannelOptions
• Default: Capacity set to 100, FullMode set to BoundedChannelFullMode.Wait
• Purpose: Defines the behavior of the task queue. The capacity determines the maximum number of tasks that can be queued, and FullMode decides the behavior when the queue is full (e.g., waiting for space to become available).

ThrowIfUnableToPersist

• Type: bool
• Default: true
• Purpose: Determines whether the service should throw an exception if it is unable to persist a task. When set to true, it ensures that task persistence failures are explicitly handled, potentially preventing data loss.

SetChannelOptions (Overloaded Methods)

• Purpose: Allows configuring ChannelOptions either by specifying the capacity directly or by providing a BoundedChannelOptions object. Adjusting these options can optimize the task queue's performance and behavior.

SetThrowIfUnableToPersist

• Purpose: Enables or disables throwing exceptions when task persistence fails. This can be critical for ensuring data integrity and handling errors appropriately.

RegisterTasksFromAssembly

• Purpose: Registers task handlers from a single assembly. This is useful for modular applications where task handlers are defined in different modules.

RegisterTasksFromAssemblies

• Purpose: Registers task handlers from multiple assemblies. Ideal for larger applications with distributed task handling logic across various modules or libraries.

SQL Server Persistence and Logging

SQL Server Storage

• Default Schema: Creates a new schema named EverTask by default. This approach avoids adding clutter to the main data schema.
• Migration Table: Places the Entity Framework Core migration table in the custom EverTask schema.
• Schema Customization: Allows specifying a different schema or using null to default to the main schema.
• Migration Handling: Option to apply database migrations automatically or handle them manually.

Serilog Integration

• Default Logging: Uses ASP.NET Core's configured ILogger by default.
• Serilog Option: Enables adding Serilog as a separate logger for EverTask, with customizable options.
• Example Configuration in appsettings.json:

  "EverTaskSerilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Default": "Information",
        "Microsoft": "Warning",
        "Microsoft.AspNetCore.SpaProxy": "Information",
        "Microsoft.Hosting.Lifetime": "Information",
        "Microsoft.EntityFrameworkCore.Database.Command": "Information"
      }
    },
    "WriteTo": [
      {
        "Name": "Console"
      },
      {
        "Name": "File",
        "Args": {
          "path": "Logs/evertask-log-.txt",
          "rollingInterval": "Day",
          "fileSizeLimitBytes": 10485760,
          "retainedFileCountLimit": 10,
          "shared": true,
          "flushToDiskInterval": "00:00:01"
        }
      }
    ],
    "Enrich": [
      "FromLogContext",
      "WithMachineName",
      "WithThreadId"
    ],
    "Properties": {
      "Application": "CliClub"
    }
  }
  
  

EverTask and EverTask.Abstractions

EverTask is complemented by the EverTask.Abstractions package, designed for use in Application projects where additional implementations are not required. This allows separation of concerns, keeping your application layer free from infrastructural code.

In your Infrastructure project, where EverTask is added, specify the assembly (or assemblies) containing IEverTask requests. This modular approach ensures that the application layer remains clean and focused, while the infrastructure layer handles task execution and management.

Serialization and deserialization of Requests for Persistence

EverTask uses Newtonsoft.Json for serializing and deserializing task requests, due to its robust support for polymorphism and inheritance, features that are limited in System.Text.Json. It is recommended to use simple objects for task requests, preferably primitives or uncomplicated complex objects, to ensure smooth serialization. In cases where EverTask is unable to serialize a request, it will throw an exception during the Dispatch method. This design choice emphasizes reliability in task persistence, ensuring that only serializable tasks are queued for execution.

Future Developments

🌟 Acknowledgements

Special thanks to jbogard for the MediaTr project, providing significant inspiration in the development of key components of this library, especially in the creation of:

TaskDispatcher.cs

TaskHandlerExecutor.cs

TaskHandlerWrapper.cs

HandlerRegistrar.cs

I have included comments within these files to acknowledge and reference the specific parts of the MediaTr project that inspired them.

Their approach and architecture have been instrumental in shaping the functionality and design of these elements.

This project includes code from MediatR, which is licensed under the Apache 2.0 License. The full text of the license can be found in the LICENSE file.