Handling Webjob Shutdown in ServiceBusTrigger Function in Azure Webjobs SDK v3

Question

I'm trying to gracefully handle webjob shutdown in my functions. I'm using v3 of the Azure Webjobs SDK and the Service Bus Extensions.

Here is a test function I've written, based on some sample code here: https://github.com/Azure/azure-webjobs-sdk-samples/blob/master/BasicSamples/MiscOperations/Functions.cs

    public async Task ProcessQueueMessageAsync([ServiceBusTrigger("testqueue")] Message message, CancellationToken cancellationToken, ILogger logWriter)
    {
        logWriter.LogError("GOT MESSAGE");
        while (!cancellationToken.IsCancellationRequested)
        {
            await Task.Delay(2000);
            logWriter.LogError("Not Cancelled");
        }

        logWriter.LogError("CANCELLED!!!");           
    }

When I shut down the webjob, though, the cancellation doesn't get logged.

I've also tried catching a TaskCanceledException as shown in this example: https://github.com/mathewc/samples/blob/master/WebJobSamples/ContinuousJobGracefulShutdown/Functions.cs

That didn't work for me either. Any ideas how to implement this in my function?

UPDATE (12/18/18):

While I still haven't figured this out, I've got a workaround that suits my purposes. In my Program class, I'm declaring a public static CancellationToken shutdownToken variable, and setting it in my Main method to

shutdownToken = new WebJobsShutdownWatcher().Token;

Then I'm registering a callback in my function as follows:

Program.shutdownToken.Register(() => logWriter.LogWarning("Webjob is shutting down!"));

George Chen George Chen · Accepted Answer · 2018-12-18T02:36:16

I refer to your link code and write a WebJob with QueueTrigger, then upload it and stop it after it has run a while. My output log shows it works fine. Maybe you can refer to it.

public static string ShutDownFilePath
    {
        get
        {
            return shutDownFile;
        }
    }

    public static void ShutdownMonitorJob(
         [QueueTrigger("myqueue")] string message,
         TextWriter log,
         CancellationToken cancellationToken)
    {

        new Thread(new ThreadStart(() =>
        {
            log.WriteLine("From thread: In about 10 seconds, the job will be signaled to stop");
            Thread.Sleep(10000);

            // Modify the shutdown file
            File.WriteAllText(shutDownFile, string.Empty);
        })).Start();

        log.WriteLine("From function: Received a message: " + message);

        while (!cancellationToken.IsCancellationRequested)
        {
            log.WriteLine("From function: Cancelled: No");
            Thread.Sleep(2000);
        }

        // Perform the graceful shutdown logic here
        log.WriteLine("From function: Cancelled: Yes");
    }

And this is my output log.The cancelled status is changed to yes.

[12/18/2018 02:14:07 > dd4ec8: INFO] From function: Cancelled: No
[12/18/2018 02:14:07 > dd4ec8: INFO] From function: Cancelled: No
[12/18/2018 02:14:07 > dd4ec8: INFO] info: Function[0]
[12/18/2018 02:14:07 > dd4ec8: INFO]       From function: Cancelled: No
[12/18/2018 02:14:07 > dd4ec8: INFO]       
[12/18/2018 02:14:09 > dd4ec8: INFO] From function: Cancelled: No
[12/18/2018 02:14:09 > dd4ec8: INFO] From function: Cancelled: No
[12/18/2018 02:14:09 > dd4ec8: INFO] info: Function[0]
[12/18/2018 02:14:09 > dd4ec8: INFO]       From function: Cancelled: No
[12/18/2018 02:14:09 > dd4ec8: INFO]       
[12/18/2018 02:14:09 > dd4ec8: SYS INFO] Detected WebJob file/s were updated, 
refreshing 
WebJob
[12/18/2018 02:14:10 > dd4ec8: SYS INFO] Status changed to Stopping
[12/18/2018 02:14:11 > dd4ec8: INFO] From function: Cancelled: Yes
[12/18/2018 02:14:11 > dd4ec8: INFO] From function: Cancelled: Yes
[12/18/2018 02:14:11 > dd4ec8: INFO] info: Function[0]
[12/18/2018 02:14:11 > dd4ec8: INFO]       From function: Cancelled: Yes
[12/18/2018 02:14:11 > dd4ec8: INFO]       
[12/18/2018 02:14:11 > dd4ec8: INFO] Executed 'Functions.ShutdownMonitorJob' 
(Succeeded, Id=9ce21c43-c113-4794-b565-81cb615a29ab)
[12/18/2018 02:14:11 > dd4ec8: INFO] info: Host.Results[0]
[12/18/2018 02:14:11 > dd4ec8: INFO]       Executed 'Functions.ShutdownMonitorJob' 
(Succeeded, Id=9ce21c43-c113-4794-b565-81cb615a29ab)
[12/18/2018 02:14:11 > dd4ec8: INFO] Job host stopped

I did more test with ServiceBus Trigger.

Here is my Program.cs content.

static void Main(string[] args)
    {

        JobHostConfiguration config = new JobHostConfiguration();
        config.UseServiceBus();
        JobHost host = new JobHost(config);
        host.RunAndBlock();

    }

And here is my Function content.

private static string shutDownFile = Path.GetTempFileName();

    public static string ShutDownFilePath
    {
        get
        {
            return shutDownFile;
        }
    }


    public static void ShutdownMonitorJob(
         [ServiceBusTrigger("myqueue")]
         string myQueueItem,
         TextWriter log,
         CancellationToken cancellationToken)
    {

        new Thread(new ThreadStart(() =>
        {
            log.WriteLine("From thread: In about 10 seconds, the job will be signaled to stop");
            Thread.Sleep(10000);

            // Modify the shutdown file
            File.WriteAllText(shutDownFile, string.Empty);
        })).Start();

        log.WriteLine("From function: Received a message: " + myQueueItem);

        while (!cancellationToken.IsCancellationRequested)
        {
            log.WriteLine("From function: Cancelled: No");
            Thread.Sleep(2000);
        }

        // Perform the graceful shutdown logic here
        log.WriteLine("From function: Cancelled: Yes");
    }

}

And this my new log pic.

I stopped the webjob and the status change normally.

Handling Webjob Shutdown in ServiceBusTrigger Function in Azure Webjobs SDK v3

1 Answers