Rewrite Http client-side PoolFlow / PoolConductor with single GraphStage about akka-http HOT 7 CLOSED

Comment by 2beaucoup
Monday Sep 05, 2016 at 13:03 GMT

Would it be safe to share the handlers between PoolFlow and the subflows? The handlers could then be created by the PoolFlow and then be injected into the subflows and could directly update the state without an additional state channel.

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Comment by jrudolph
Monday Sep 05, 2016 at 13:59 GMT

You mean to rely on all of the stages being run in the same context so that it would be safe to manipulate state of another stage? I don't think that's a good idea ;) We should try to avoid tricks.

The PoolSlot seems to me like a useful abstraction over a connection that automatically reconnects if the connection gets closed + some meta messages that transport (or manipulate) the current state.

The PoolConductor on top of that tries to keep track of the state of its slots and schedules requests in a best-effort way.

That seems to me like a clean separation.

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Comment by 2beaucoup
Monday Sep 05, 2016 at 14:12 GMT

You mean to rely on all of the stages being run in the same context so that it would be safe to manipulate state of another stage? I don't think that's a good idea ;) We should try to avoid tricks.

Agreed. SlotCommands in and SlotEvents out it is then.

The PoolSlot seems to me like a useful abstraction over a connection that automatically reconnects if the connection gets closed + some meta messages that transport (or manipulate) the current state.

But the (re-)connection is triggered by the conductor, no?

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Comment by jrudolph
Monday Sep 05, 2016 at 14:20 GMT

But the (re-)connection is triggered by the conductor, no?

Right now, yes, but we could (and should) change it if it simplifies the protocol.

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Comment by 2beaucoup
Monday Sep 05, 2016 at 14:23 GMT

But only the conductor does really know if a (re-)connection is actually necessary.

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Comment by jrudolph
Monday Sep 05, 2016 at 14:33 GMT

In the simplest case, the slot opens a connection if it has request(s) pending (or if was triggered by ConnectEagerlyCommand).

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Duplicate of #20

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