Notifications¶

NCronJob provides a way to get notified when a job is done. For this, implement a IJobNotificationHandler<TJob> and register it in your DI container.

builder.Services.AddNCronJob(options =>
    options.AddCronJob<PrintHelloWorld>(j => 
    {
        // Every minute and optional parameter
        j.WithCronExpression("* * * * *")
         .WithParameter("Hello World");
    })
    .AddNotificationHandler<MyJobNotificationHandler>());

This allows to run logic after a job is done. The JobExecutionContext and the Exception (if there was one) are passed to the HandleAsync method.

Service scope

The notification handler is resolved from its own dependency injection scope. Scoped services (for example an Entity Framework DbContext) are therefore not shared with the job instance. Pass data from the job to the handler via IJobExecutionContext.Output instead.

Exceptions thrown by a notification handler are caught and don’t affect the job outcome.

public class MyJobNotificationHandler : IJobNotificationHandler<MyJob>
{
    private readonly ILogger<MyJobNotificationHandler> logger;

    public MyJobNotificationHandler(ILogger<MyJobNotificationHandler> logger)
    {
        this.logger = logger;
    }

    public Task HandleAsync(IJobExecutionContext context, Exception? exception, CancellationToken token)
    {
        if (exception is not null)
        {
            logger.LogError(exception, "Job failed");
        }
        else
        {
            logger.LogInformation("Job was successful");
            logger.LogInformation("Output: {Output}", context.Output);
        }

        return Task.CompletedTask;
    }
}