hosted service (background service) in asp.net core restart in each Publish azure

Question

I have a hosted service that sends an email each 3 days my problem is when I publish in azure the service restart the calculation of 3 days

  public Task StartAsync(CancellationToken cancellationToken)
        {

            _timer = new Timer(SendReminderEmail, null, TimeSpan.FromDays(3), TimeSpan.FromDays(3));
             

            return Task.CompletedTask;
        }

there is a solution to this problem? for example, I publish sure azure Tuesday I expect I have an email Friday but if I publish another time in azure Wednesday it will calculation from Wednesday :/

thank you

Answer 1

There are a few different options that will likely fit your needs better. Of the three I would choose Functions as silent mentioned.

1. Webjobs are specifically for running background tasks separated from your main application. They can run on a timer and be deployed separately from your main app.
2. This is a good use case for Functions, which were build on top of Webjobs and add the option of consumtion-based billing where you only pay for the resources you actually use, as opposed to a traditional App Service account where you pay hourly even if your app is standing idle. If you have an App Service already with excess capacity, you could also deploy it there.
3. Make use of scheduled delivery in either Service Bus or Storage Queues. Once your process is done running it schedules a message for three days from now. The downside is this can be be a bit brittle- if the process fails it won't create the new message and the loop will be broken.