QUESTION: Is graceful shutdown possible?

[stap123]

Is it possible to know when a function is about to be terminated by the runtime to perform a graceful shutdown?

It would be good to be able to get a notification of when this about to happen and do some logging at a bare minimum.

Thank you 😃

[ssa3512]

Based on this comment you should be able to inject IHostApplicationLifetime into your function class and use the ApplicationStopping cancellation token to detect shutdown.

[fabiocav]

Yes, you can use the application lifetime to get notified, but we're actively working on enhancements to enable a behavior that puts the app into a drain mode.

@nzthiago will be posting updates on this as we reach preview/GA states.

[stap123]

@fabiocav Is there somewhere we can follow to see what's currently being worked on somewhere specifically these updates will be published?

[nzthiago]

@fabiocav Is there somewhere we can follow to see what's currently being worked on somewhere specifically these updates will be published?

I just created this entry on the host repo that you can follow for updates Azure/azure-functions-host#7772

It's a mostly internal implementation but we'll make sure to update the CancellationToken documentation with an example as well.

[nzthiago]

Please note that at the moment the .NET isolated (i.e., out of process worker) doesn't have Cancellation Token support. To be surfaced to the .NET isolated worker this depends on a host update related to this feature Azure/azure-functions-host#7785, and requires further design decisions and prioritization, so for now the documentation here is up to date. Note that even though the cancellation token isn't flowing into the out of proc function, a graceful period should still be given to your function as per this work in Consumption and Premium plans.