Shutdown Gracefully on Kill or Interrupt.

[jsolman]

With this PR Interrupt due to Control+C or process kill will properly be caught and cause the node to be stopped in the same way as typing exit.

[erikzhang]

In fact, I prefer Control+C to kill the process directly. Sometimes when debugging, you will want to use Control+C when you want to close the process immediately.

[jsolman]

It still generally closes in less than 1 second. It is a best practice to shutdown cleanly.

[vncoelho]

I also like this, Erik...hauajaha
ctrl+c is the power. I never had problem with it.

But I think @jsolman wants to avoid crashes.

[jsolman]

Sometimes when debugging, you will want to use Control+C when you want to close the process immediately.

@erikzhang
You can send a more forceful type of signal if you want to kill it immediately.

[shargon]

A lot of red message appears before close

Maybe we could avoid this to prevent "scares"

[jsolman]

@shargon I was looking for the best way to do it. I haven’t found a trivial way yet since we don’t have a top level actor.

[jsolman]

I’ll see if I can find a way to get rid of them also in this PR after I finish the consensus PR I’m working on now

[vncoelho]

I think that maybe this patch can come to neo-cli 3.0, however, let's not modify 2.x.

Is there something else to be done here, @jsolman?

@erikzhang, I also prefer ctrl+c to kill direct. However, in the last core developers meeting I think that the majority agreed that we should avoid crashes...aehauhuea

[jsolman]

There is no reason this should not be on both branches IMO.

[vncoelho]

neo-cli 2.x can historically stay with its behavior, this will not really impact in anything critical.

However, it may be a good practice for Neo 3, if the majority agrees.
As I said, I prefer ctrl+c to be quick and exit, but, without crashing anything critical.

[shargon]

conflicts

[lock9]

Hi @jsolman, could you solve the conflicts? Do you want us to solve it for you?

[shargon]

My review at #428

[shargon]

@vncoelho does this work well for you in linux?

[vncoelho]

@shargon, with this PR the ctrl +c is working on linux. Looks good

[shargon]

@vncoelho with my patch is working too?

[jsolman]

Thanks for rebasing.

[vncoelho]

I did not test yet, @shargon. I want to finish the P2P...aheuahueaea

[vncoelho]

@shargon, In fact, ctrl+c has been always working on linux.
Just failing on that other PR that you made and closed...aehauheuaea ajajaja

I still need to test the patch you opened.

But is this an agreement that this change is good?
I got some Akka errors after killing it with ctrl+c. But the same error was obtained when typing exit.
I think it happens when we kill it very soon, before it really initialized.
I need to double test if I also get these errors without this PR!

[vncoelho]

@shargon, @jsolman and @erikzhang,

This works nice and ok with ctrl+c.

However, if the client is still killed very fast (just after initialization), this error is still obtained:

[ERROR][08/19/2019 19:37:29][Thread 0004][akka://NeoSystem/system/IO-TCP/$a] Monitored actor [[akka://NeoSystem/user/$b#1681348270]] terminated
Cause: Akka.Actor.DeathPactException: Monitored actor [[akka://NeoSystem/user/$b#1681348270]] terminated
   at Akka.Actor.ActorBase.Unhandled(Object message)
   at Akka.Actor.ActorBase.AroundReceive(Receive receive, Object message)
   at Akka.Actor.ActorCell.ReceiveMessage(Object message)
   at Akka.Actor.ActorCell.AutoReceiveMessage(Envelope envelope)
   at Akka.Actor.ActorCell.Invoke(Envelope envelope)

[shargon]

In my windows works well, but this exceptions is something to fix in other PR, i think

[vncoelho]

@shargon, I prefer to wait for @erikzhang or @superboyiii approval.

[vncoelho]

@Tommo-L, can you give a look at this?
#469

[lock9]

It fixes the control+c problem, thanks.
It prints some messages but I think they are ok.
On my windows machine, without this, control-c makes neo-cli unresponsive.

[Tommo-L]

@Tommo-L, can you give a look at this?
#469

I think it also can fix the exit problem. I'll close #469

[vncoelho]

That is why I did not want to merge it and told to wait for @erikzhang and @superboyiii review's.
I think it should be reverted. It is quite bad as it is. Application is taking tremendous take to be finished when errors are presented, during tests and experimental phase this makes no sense.

[jsolman]

The red messages on Akka are just notifying the actors shutdown. A different top level actor needs to be added to avoid them.

I have run this on Linux a long time and never saw the hang you are describing @vncoelho. What are the steps you are using to reproduce the hang? What hardware are you running on? What flavor of Linux?