Add suspend, resume and reconnect methods #64
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Signed-off-by: Piotr Piotrowski <piotr@synadia.com>
Sources/Nats/NatsConnection.swift
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| if self.state == .connected { | ||
| self.state = .suspended | ||
| try await disconnect() | ||
| self.fire(.disconnected) |
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Should suspended and disconnect be different events? even though suspension technically closes the connection from the clients perspective we are keeping subscription state whereas disconnect should also clear that state?
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We were discussing those with @piotrpio
We should never clear the state of subscriptions and we should always recover them when reconnecting/resuming.
The only difference is that if you disconnect because of suspend, client will not try to reconnect automatically. In all other cases, it will.
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I guess my point is about the event types more than the state. For example when you call close() we're emitting closed as opposed to disconnected
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Yeah, I was wondering weather to add a new event type or not. I was not sure how useful it would be to add a new event type, separate from "disconnected". Now that I think about it, having separate event types would mean you would be able to easily catch and separate instances of disconnects not triggered by the client and potentially take some action. Meanwhile, suspending is always initiated by the library and thus may not need a callback (or have a different one). I'll add the new event type.
Sources/Nats/NatsConnection.swift
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| } | ||
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| func resume() async throws { | ||
| guard self.state == .suspended else { |
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should we make sure state changes are synchronized to avoid races?
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Good point, changed 👍
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do you think checking the state than changing it could also be racy? if we ran them in the event loop we shouldn't need locks or we can lock read-modify if it won't cause deadlocks.
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So you mean managing the state as tasks in event loop right?
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yes, using eventloop.execute { }
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I'm really not sure what would be the best approach here, but possibly it would be safer to execute these on event loop.
I took a stab at this, please take a look at the latest changes.
Signed-off-by: Piotr Piotrowski <piotr@synadia.com>
Signed-off-by: Piotr Piotrowski <piotr@synadia.com>
Signed-off-by: Piotr Piotrowski <piotr@synadia.com>
Sources/Nats/NatsConnection.swift
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| Task { | ||
| self.state = .closed | ||
| do { | ||
| try await self.disconnect() |
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disconnect is essentially a call to channel.close() and can be done without spawning a Task.
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You're right. I wanted to re-use disconnect method but it does not make sense here.
Sources/Nats/NatsConnection.swift
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| self.state = .closed | ||
| try await disconnect() | ||
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| let eventLoop = self.channel?.eventLoop ?? MultiThreadedEventLoopGroup.currentEventLoop! |
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should we guard these instead? What are the cases channel being nil other than connect() call not being done at this point?
Signed-off-by: Piotr Piotrowski <piotr@synadia.com>
Signed-off-by: Piotr Piotrowski piotr@synadia.com