Send graceful shutdown notification via HTTP

[Tratcher]

RE: aspnet/Hosting#846

Today ANCM sends CTL+C to notify the child process of graceful shutdowns. This triggers shutdown events in Hosting, stops the server, drains requests, etc.. Unfortunately Azure Web Sites sandbox blocks all out-of-proc console APIs, including CTL+C. Sending the signal fails with an error and ANCM immediately terminates the child process.

Proposal:
ANCM will now send this notification via an HTTP request that will be handled by the IISMiddleware. The CTL+C will remain for back compat. We need to confirm if the debugger tooling is expecting this CTL+C.

Note 1.x sites on azure will not be fixed by this solution, only 2.x apps + a new ANCM.

Order of operations:

• Start the shutdown timer
• Send the HTTP shutdown request, wait for response.
• Send the CTL+C.
• If both failed, log the failure and terminate the process immediately
• Otherwise wait for the process to end.
• If the timeout expires then terminate the process and log the failure, including any notes on if the shutdown request returned the expected response.

Request details:
POST [/BasePath]/iisintegration HTTP/1.1
MS-ASPNETCORE-EVENT: shutdown
(no body)

Expected response:
HTTP/1.1 202 Accepted
(no body)

Other notes:
ANCM already filters out an external MS-* headers.
IISMiddleware already rejects requests missing the MS-ASPNETCORE-TOKEN header.
IISMiddleware is only added to the app if ANCM environment variables are present at startup.

[JunTaoLuo]

IISIntegration change is in.

[DamianEdwards]

@shirhatti @pan-wang do we have an ETA and release plan for this change?

[pan-wang]

I have done the prototype. Will run my private with new IISIntegration change today. ETA for code complete is this Friday. @shirhatti<https://github.com/shirhatti> is working on the release plan.

…

________________________________ From: Damian Edwards <[email protected]> Sent: Wednesday, June 28, 2017 1:24:55 AM To: aspnet/AspNetCoreModule Cc: pan-wang; Mention Subject: Re: [aspnet/AspNetCoreModule] Send graceful shutdown notification via HTTP (#115) @shirhatti<https://github.com/shirhatti> @pan-wang<https://github.com/pan-wang> do we have an ETA and release plan for this change? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#115 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/ARVK20pZevTBjT7ODfoiPykSIYOf1go0ks5sIeOngaJpZM4OC7Wh>.

[Plasma]

Hi team, any update on whether this change was rolled out to Azure AppService to support graceful shutdowns? Thank you

[Tratcher]

The change requires both a new version of ANCM and the final release of ASP.NET Core 2.0. Both are scheduled for release and azure deployment in the coming weeks.

[pan-wang]

the change was checked in. Close the issue

[rollsch]

What libraries and versions specifically do I need to ensure I have this new change?

[shirhatti]

ANCM >= 1.0.1983
Microsoft.AspNetCore.IISIntegration (or Microsoft.AspNetCore.All) >= 2.0.0

[rollsch]

Thank you