Problem Statement: Develop a hosted service that runs in a dotnet core app. This service needs to support dependency injection and logging configuration from the app.
Frameworks:
Asp.Net core 3.0 (This works in 2.2 as well)
Step 1:
In Startup.cs add this hosted service to Service Collection
services.AddHostedService();
Step 2:
I just want to highlight of couple of key areas from snippet below.
- Hosted services are singleton, so you cannot inject scoped or transient services.
- Service Provider can be used to create scope from which you can get all required services from dependency container.
- Cancellation token is the key service that can be used to handle graceful shutdown and also keep the service running in the background.
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| public class EmailBackgroundService : BackgroundService | |
| { | |
| private readonly IServiceProvider _serviceProvider; | |
| private readonly ILogger<EmailBackgroundService> _logger; | |
| public EmailBackgroundService(IServiceProvider serviceProvider, ILogger<EmailBackgroundService> logger) | |
| { | |
| _serviceProvider = serviceProvider; | |
| _logger = logger; | |
| } | |
| protected override async Task ExecuteAsync(CancellationToken stoppingToken) | |
| { | |
| while (!stoppingToken.IsCancellationRequested) | |
| { | |
| await RunSomeprocess(); | |
| await Task.Delay(5000, stoppingToken); | |
| } | |
| } | |
| private async Task RunSomeprocess() | |
| { | |
| using var providerScope = _serviceProvider.CreateScope(); | |
| var userService = providerScope.ServiceProvider.GetService<IUserService>(); | |
| _logger.Log( LogLevel.Information , $"{userService.GetUserId()}"); | |
| } | |
| } |
Have fun!
giridharprakash.me 