Remove code to shutdown EventLoopGroup in FluentQueuesDriver

[thuotdwz]

This will fix error message:

ERROR: Cannot schedule tasks on an EventLoop that has already shut down. This will be upgraded to a forced crash in future SwiftNIO versions.

when using Ctrl+C to shut down application. EventLoopGroup here is not owned by FluentQueuesDriver and used by other objects during shutdown procedure

Fixes #6

[thuotdwz]

Can we please add this fix to a release?

[m-barthelemy]

I added this exactly because I was getting issues during shutdown (using Ctrl+C) - the app was hanging.
I'm unable to reproduce the ERROR: Cannot schedule tasks on an EventLoop that has already shut down message.

[thuotdwz]

I create new vapor template using vapor-beta new command, then add your package dependency. Just below the line

app.databases.use(.sqlite(.file("db.sqlite")), as: .sqlite)

I add two lines

app.queues.use(.fluent(.sqlite))
app.migrations.add(JobModelMigrate())

If I run this template app on Mac OS and do ctrl+c I instantly see error messages

[ NOTICE ] Server starting on http://127.0.0.1:8080
^C
ERROR: Cannot schedule tasks on an EventLoop that has already shut down. This will be upgraded to a forced crash in future SwiftNIO versions.
ERROR: Cannot schedule tasks on an EventLoop that has already shut down. This will be upgraded to a forced crash in future SwiftNIO versions.
ERROR: Cannot schedule tasks on an EventLoop that has already shut down. This will be upgraded to a forced crash in future SwiftNIO versions.
ERROR: Cannot schedule tasks on an EventLoop that has already shut down. This will be upgraded to a forced crash in future SwiftNIO versions.
Fatal error: leaking promise created at (file: "/Users/thuotdwz/app/.build/checkouts/swift-nio/Sources/NIO/SelectableEventLoop.swift", line: 214): file /Users/thuotdwz/app/.build/checkouts/swift-nio/Sources/NIO/SelectableEventLoop.swift, line 214

If you try the same steps do you also see this error?

[thuotdwz]

Hi, have you had a chance to check on this bug fix?

[m-barthelemy]

Not yet unfortunately.
If you still have your sample project created from the vapor-beta new command and can push it to Github, I will clone it and use it to try reproducing the error (and hopefully fix it if it's related to this package).

[thuotdwz]

sure, I uploaded a sample app here https://github.com/thuotdwz/app

All you need to see the bug is run "swift run" and then type Ctrl+c once started

[m-barthelemy]

Seems to help, finally merging this.