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Refactor provider shutdown and pending flows #240

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Merged
merged 4 commits into from
Jun 13, 2020
Merged

Refactor provider shutdown and pending flows #240

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3239c9f
refactor provider close and pending flows
artemredkin Jun 12, 2020
606cb87
Merge branch 'master' into provider_pending_close_fix
artemredkin Jun 12, 2020
a63485e
review fixes
artemredkin Jun 12, 2020
87da072
remove debug output
artemredkin Jun 12, 2020
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12 changes: 8 additions & 4 deletions Sources/AsyncHTTPClient/ConnectionPool.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -80,12 +80,13 @@ final class ConnectionPool {
if let existing = self.providers[key], existing.enqueue() {
return existing
} else {
// Connection provider will be created with `pending = 1`
let provider = HTTP1ConnectionProvider(key: key,
eventLoop: taskEventLoop,
configuration: self.configuration,
pool: self,
backgroundActivityLogger: self.backgroundActivityLogger)
let enqueued = provider.enqueue()
assert(enqueued)
self.providers[key] = provider
return provider
}
Expand Down Expand Up @@ -263,8 +264,6 @@ struct ConnectionKey: Hashable {
/// of concurrent requests as it has built-in politeness regarding the maximum number
/// of concurrent requests to the server.
class HTTP1ConnectionProvider {
struct ProviderClosedError: Error {}

/// The client configuration used to bootstrap new requests
private let configuration: HTTPClient.Configuration

Expand Down Expand Up @@ -318,7 +317,7 @@ class HTTP1ConnectionProvider {
self.state.assertInvariants()
}

private func execute(_ action: Action, logger: Logger) {
func execute(_ action: Action, logger: Logger) {
switch action {
case .lease(let connection, let waiter):
// if connection is became inactive, we create a new one.
Expand Down Expand Up @@ -494,6 +493,11 @@ class HTTP1ConnectionProvider {
$0.promise.fail(HTTPClientError.cancelled)
}

if available.isEmpty, leased.isEmpty {
self.closePromise.succeed(())
return self.closePromise.futureResult.map { clean }
}

EventLoopFuture.andAllComplete(leased.map { $0.cancel() }, on: self.eventLoop).flatMap { _ in
EventLoopFuture.andAllComplete(available.map { $0.close() }, on: self.eventLoop)
}.whenFailure { error in
Expand Down
4 changes: 2 additions & 2 deletions Sources/AsyncHTTPClient/ConnectionsState.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,7 @@ extension HTTP1ConnectionProvider {
private var openedConnectionsCount: Int = 0

/// Number of enqueued requests, used to track if it is safe to delete the provider.
private var pending: Int = 1
private var pending: Int = 0
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nice! I left a bunch of stuff like the following comments in the code

        /* BEGIN workaround for #232, this whole block is to be replaced by the commented out line below */
        // not closing the provider here (https://github.com/swift-server/async-http-client/issues/232)
        var state = self.http1ConnectionProvider.state.testsOnly_getInternalState()
        if state.pending == 1, state.waiters.isEmpty, state.leasedConnections.isEmpty, state.openedConnectionsCount == 0 {
            state.pending = 0
            self.http1ConnectionProvider.state.testsOnly_setInternalState(state)
        }
        self.http1ConnectionProvider.closePromise.succeed(())
        /* END workaround for #232 */

and

            // cleanup
            // this cleanup code needs to go and use HTTP1ConnectionProvider's API instead

I believe we can also delete all this code then.

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I was able to delete the workaround, some clean up code, and I was able to replace some cleanup with API calls instead of direct state manipulation. Currently there are 3-4 tests that manipulate state directly (they all need the state to be near the limit), do you want me to fix it here or when I get to #232?

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no, let's fix them in a followup. It's super awesome you could remove the workaround


init(maximumConcurrentConnections: Int = 8, eventLoop: EventLoop) {
self.maximumConcurrentConnections = maximumConcurrentConnections
Expand Down Expand Up @@ -148,7 +148,7 @@ extension HTTP1ConnectionProvider {
return .none
}
case .closed:
return .fail(waiter, ProviderClosedError())
return .fail(waiter, HTTPClientError.alreadyShutdown)
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@artemredkin from what I can tell, no test noticed that this error changed which probably means no test is getting this error ;). I think we should probably add a test case that tests this condition.

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filed #244

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Specific test is a good idea, yes, though this error was picked up by a test, just not reliably :)

}
}

Expand Down
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