HTTP API Prevents Graceful Shutdown w/ Chrome

[spble]

Description

With the inclusion of the graceful_shutdown function in the RESTful HTTP API, Lighthouse should properly shutdown on an interrupt such as Ctrl+C, however it does not.

Present Behaviour

1. Start the beacon_node
2. Make a HTTP request to the API
3. Shutdown the beacon_node
4. beacon_node hangs indefinitely, until...
5. Make another HTTP request to the API
6. beacon_node exits.

Expected Behaviour

1. Start the beacon_node
2. Make a HTTP request to the API
3. Shutdown the beacon_node
4. beacon_node exits.

Steps to resolve

There are several issues on the hyper github which may assist in resolving this issue, these must be revised and a solution devised that is elegant and encompasses all of the client services (API, RPC, etc.).

e.g. hyperium/hyper#1681

[paulhauner]

Note: this issue is only present when using Chrome to access the API. Using curl does not result in Hyper "hanging".

This leads me to believe that Chrome is keeping a connection alive and Hyper is acting correctly.

I still think we should leave this open until we figure out exactly what's going on with Chrome :)

[adaszko]

I'm gonna take a look at this issue. Ping me if you have any additional information please.

[adaszko]

Turns out Chrome doesn't cause the Hyper HTTP server to hang. The shutdown simply takes a bit longer.

Here's how to the ^C looks with Firefox:

And with Chrome:

It can be seen that Chrome sends keepalives until it's connection timeout elapses. It's a separate confounding factor that Chrome has larger connection timeout settings than other browsers: 300 seconds compared to e.g. Firefox'es 90 (by default).

My opinion based on that is that the issue can be closed as there's nothing the built-in HTTP server does wrong.

[paulhauner]

Great, thanks @adaszko!

I'm confident in saying that this is expected and reasonable behavior and that this issue can be closed :)

[surya-prakash-susarla]

Hey folks, quick question, I have been trying to create a server which simply shuts down after a GET request is received (an OAuth response scenario) and I seem to be running into the same issue. Using hyper with Safari works perfectly but with Chrome I run into the issue above where the exit only happens after the second request is made. Can anyone suggest a workaround for this?