implement lazy selector registration #388
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Lukasa
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Lukasa
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Cool, mostly looks really good! Some notes!
| case fresh | ||
| case registered | ||
| case lazilyRegistered // register() has been run but the selector doesn't know about it yet | ||
| case fullyRegistered // fully registered, ie. the selector knows about it |
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Nit: I don't love these names. Can we call the new state preRegistered, maybe?
Sources/NIO/BaseSocketChannel.swift
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| case activate | ||
| case register | ||
| case registerLazily | ||
| case registerFully |
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Similarly, these names aren't necessarily right. Maybe beginRegistration and completeRegistration?
| if self.lifecycleManager.isRegisteredLazily { | ||
| try! becomeFullyRegistered0() | ||
| if self.lifecycleManager.isRegisteredFully { | ||
| becomeActive0(promise: promise) |
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Do these callouts not get triggered by register0?
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@Lukasa right now register0 only does the pre-registration. I didn't change its name as it's on ChannelCore. But we could obviously rename it to preRegister0
| let error = EventLoopError.shutdown | ||
| self.pipeline.fireErrorCaught0(error: error) | ||
| self.close0(error: error, mode: .all, promise: nil) | ||
| promise?.fail(error: error) |
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I think we should just pass the promise into self.close0(...) which will ensure correct ordering as well.
So basically:
self.close0(error: error, mode: .all, promise: promise)
Sources/NIO/EventLoop.swift
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| } | ||
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| /// Is this `SelectableEventLoop` still open (ie. not shutting down or shut down) | ||
| public var isOpen: Bool { |
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@weissi this is not safe as lifecycleState is not thread-safe. Maybe change to internal and assert that the caller is the EventLoop thread ?
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@normanmaurer it's fine as SelectableEventLoop is an internal type (not public) but regardless I changed this to internal and added an assertion
Tests/NIOTests/ChannelTests.swift
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| XCTAssertNoThrow(try server.register().wait()) | ||
| XCTAssertNoThrow(try server.eventLoop.submit { | ||
| XCTAssertFalse(server.isActive) | ||
| }.wait()) |
| } | ||
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| func testLazyRegistrationWorksForServerSockets() throws { | ||
| let group = MultiThreadedEventLoopGroup(numThreads: 1) |
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add:
defer {
XCTAssertNoThrow(try group.syncShutdownGracefully())
}| } | ||
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| func testLazyRegistrationWorksForClientSockets() throws { | ||
| let group = MultiThreadedEventLoopGroup(numThreads: 1) |
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add:
defer {
XCTAssertNoThrow(try group.syncShutdownGracefully())
}
Motivation: Previously we would eagerly register any fd with the selector (epoll/kqueue) which works well with kqueue. With epoll however, you'll get `EPOLLHUP` immediately if you supplied a socket that hasn't had connect/bind called on it. We got away with this because we took quite a bit of care to always make sure we call connect/bind pretty much immediately after we registered it. And crucially before we ever asked the selector to tell us about new events. Modifications: made selector registration lazy (when we try activating the channel by calling connect/bind) Result: the user can now register and connect whenever they feel like it.
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Thanks @weissi ... merged :) |
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Motivation:
Previously we would eagerly register any fd with the selector
(epoll/kqueue) which works well with kqueue. With epoll however, you'll
get
EPOLLHUPimmediately if you supplied a socket that hasn't hadconnect/bind called on it.
We got away with this because we took quite a bit of care to always make
sure we call connect/bind pretty much immediately after we registered
it. And crucially before we ever asked the selector to tell us about
new events.
Modifications:
made selector registration lazy (when we try activating the channel by
calling connect/bind)
Result:
the user can now register and connect whenever they feel like it, fixes #380