I have a webjob in Azure, hosted on an App Service that is not used for anything. I am currently deploying my webjob from Visual Studio, but this will change in the future as it's not in production. It's a .NET Core 3.1 application webjob that compiles to an EXE, but that shouldn't matter to this question (and I'm aware of Azure Functions, but that is also not a part of my question).
The webjob is a continous webjob triggered by a queue. I have set it up to run 10 batches simultaneously. I have looked online for answers, but I have found unclear answers.
My question is: Let's say I have 3 jobs running. Then I deploy a new version of the EXE file. This seems to work without problems. But what happens to the jobs that are running? Will they continue running to the end? Or will it fail and stop? I haven't quite managed to sort that out and I wanted to ask here in case someone have helpful experience on this.
My queue related config is like this, if that's helpful:
.ConfigureWebJobs(b =>
{
b.AddAzureStorageCoreServices();
b.AddAzureStorage(a =>
{
a.BatchSize = 10;
a.NewBatchThreshold = 5;
a.MaxDequeueCount = 1;
a.MaxPollingInterval = TimeSpan.FromSeconds(20);
});
})
Thank you!
But what happens to the jobs that are running? Will they continue running to the end? Or will it fail and stop?
When a WebJob that uses the WebJobs SDK picks up a message from a queue, it acquires it with a 10 minutes lease. If the job process dies while processing the message, the lease expires after 10 minutes and the message goes back in the queue. If the WebJob is restarted, it will pick that message again. The message is only deleted if the function completes successfully.
Therefore, if the job dies and restarts immediately, like in the case of a redeploy, it might take up to 10 minutes to pick again the message. Also, because of this, it is recommended to either save state yourself or make the function idempotent.
In the WebJobs Dashboard you will see two invocations for the same message. One of them will be marked as Never Finished because the function execution never completed.
Unfortunately, there is no out of the box solution to prevent jobs from running during deploy. You would have to create your own logic that notifies (through a queue message?) that a deploy is about the start and then aborts the host. The host abort will wait for any existing function to stop and will prevent new ones from starting. However, this is a very tricky situation if you have multiple instances of the webjob because only one of them will get the notification.