Azure timertriggered webjob hangs randomly

Question

I want to schedule a timertriggered method to call other methods but somehow the CronJob method won't run if I use it to call one of my own methods, I simply get this console output: " Found the following functions: ...ProcessQueueMessage ...Functions.CronJob Job host started "

and nothing else happens for a couple of minutes and then it might suddenly start working. But if I only use the CronJob() method for running it's own Console.WriteLine("Timer job fired") statement everything works.

I have been trying to find a solution to this problem for hours now but no one seems to have the same problem. Any ideas on what I'm doing wrong?

public static void CronJob([TimerTrigger("*/3 * * * * *", RunOnStartup = true)] TimerInfo timerInfo)
    {
        Console.WriteLine("Timer job fired! ");
        DoTask();

    }

    private static void DoTask()
    {
        Console.WriteLine("Doing task...");
    }

Main method:

static void Main()
    {
        var config = new JobHostConfiguration();

        if (config.IsDevelopment)
        {
            config.UseDevelopmentSettings();
        }

        var host = new JobHost(config);
        config.UseTimers();
        // The following code ensures that the WebJob will be running continuously
        host.RunAndBlock();
    }

Are you seeing these problems when running locally, on an Azure Web App instance, or both? — Rob Reagan, Mar 04 '18 at 18:13
At least when running locally it happens all the time. EDIT: it happens on both — Rem, Mar 04 '18 at 18:42
Can you set the JobHostConfiguration.Tracing.ConsoleLevel to Verbose and see if this sheds light on things? I'm wondering if you're not experiencing an issue with the TimerTrigger singleton lock. — Rob Reagan, Mar 04 '18 at 18:46
While we are at the topic is it common practice to call other methods from a TimeTrigger method? — Rem, Mar 04 '18 at 18:47
Absolutely, other methods are often called from a TimerTrigger method. — Rob Reagan, Mar 04 '18 at 18:54
Could you elaborate on the possible singleton lock issue? This problem is really getting on my nerves now — Rem, Mar 04 '18 at 20:32

Tom Sun - MSFT · Accepted Answer · 2018-03-05T05:33:40.943

Any ideas on what I'm doing wrong?

According to your description, it is not related with whether you call code directly. The root reason is that a blob lease (the Singleton Lock) is taken for a default time of 30 seconds.

As Rob Reagan mention that you could set JobHostConfiguration.Tracing.ConsoleLeve to Verbose. When the webjob hangs you could get the information "Unable to aquire Singleton lock".

For more detail info you could refer to this issue.

When the listener starts for a particular TimerTrigger function, a blob lease (the Singleton Lock) is taken for a default time of 30 seconds. This is the lock that ensures that only a single instance of your scheduled function is running at any time. If you kill your console app, that lease will still be held until it expires naturally

Thank you very much for your help, that link was also really useful! — Rem, Mar 05 '18 at 08:54

Azure timertriggered webjob hangs randomly

1 Answers1