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SSLContextCache: use DispatchQueue instead of NIOThreadPool #368

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Merged
merged 1 commit into from
May 13, 2021
Merged

SSLContextCache: use DispatchQueue instead of NIOThreadPool #368

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2 changes: 0 additions & 2 deletions Sources/AsyncHTTPClient/ConnectionPool.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -109,8 +109,6 @@ final class ConnectionPool {
self.providers.values
}

self.sslContextCache.shutdown()

return EventLoopFuture.reduce(true, providers.map { $0.close() }, on: eventLoop) { $0 && $1 }
}

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53 changes: 3 additions & 50 deletions Sources/AsyncHTTPClient/SSLContextCache.swift
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Expand Up @@ -12,69 +12,22 @@
//
//===----------------------------------------------------------------------===//

import Dispatch
import Logging
import NIO
import NIOConcurrencyHelpers
import NIOSSL

class SSLContextCache {
private var state = State.activeNoThread
private let lock = Lock()
private var sslContextCache = LRUCache<BestEffortHashableTLSConfiguration, NIOSSLContext>()
private let threadPool = NIOThreadPool(numberOfThreads: 1)

enum State {
case activeNoThread
case active
case shutDown
}

init() {}

func shutdown() {
self.lock.withLock { () -> Void in
switch self.state {
case .activeNoThread:
self.state = .shutDown
case .active:
self.state = .shutDown
self.threadPool.shutdownGracefully { maybeError in
precondition(maybeError == nil, "\(maybeError!)")
}
case .shutDown:
preconditionFailure("SSLContextCache shut down twice")
}
}
}

deinit {
assert(self.state == .shutDown)
}
private let offloadQueue = DispatchQueue(label: "io.github.swift-server.AsyncHTTPClient.SSLContextCache")
}

extension SSLContextCache {
private struct SSLContextCacheShutdownError: Error {}

func sslContext(tlsConfiguration: TLSConfiguration,
eventLoop: EventLoop,
logger: Logger) -> EventLoopFuture<NIOSSLContext> {
let earlyExitError: Error? = self.lock.withLock { () -> Error? in
switch self.state {
case .activeNoThread:
self.state = .active
self.threadPool.start()
return nil
case .active:
return nil
case .shutDown:
return SSLContextCacheShutdownError()
}
}

if let error = earlyExitError {
return eventLoop.makeFailedFuture(error)
}

let eqTLSConfiguration = BestEffortHashableTLSConfiguration(wrapping: tlsConfiguration)
let sslContext = self.lock.withLock {
self.sslContextCache.find(key: eqTLSConfiguration)
Expand All @@ -88,7 +41,7 @@ extension SSLContextCache {

logger.debug("creating new SSL context",
metadata: ["ahc-tls-config": "\(tlsConfiguration)"])
let newSSLContext = self.threadPool.runIfActive(eventLoop: eventLoop) {
let newSSLContext = self.offloadQueue.asyncWithFuture(eventLoop: eventLoop) {
try NIOSSLContext(configuration: tlsConfiguration)
}

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3 changes: 1 addition & 2 deletions Tests/AsyncHTTPClientTests/SSLContextCacheTests+XCTest.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -25,10 +25,9 @@ import XCTest
extension SSLContextCacheTests {
static var allTests: [(String, (SSLContextCacheTests) -> () throws -> Void)] {
return [
("testJustStartingAndStoppingAContextCacheWorks", testJustStartingAndStoppingAContextCacheWorks),
("testRequestingSSLContextWorks", testRequestingSSLContextWorks),
("testRequestingSSLContextAfterShutdownThrows", testRequestingSSLContextAfterShutdownThrows),
("testCacheWorks", testCacheWorks),
("testCacheDoesNotReturnWrongEntry", testCacheDoesNotReturnWrongEntry),
]
}
}
32 changes: 18 additions & 14 deletions Tests/AsyncHTTPClientTests/SSLContextCacheTests.swift
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Expand Up @@ -18,45 +18,47 @@ import NIOSSL
import XCTest

final class SSLContextCacheTests: XCTestCase {
func testJustStartingAndStoppingAContextCacheWorks() {
SSLContextCache().shutdown()
}

func testRequestingSSLContextWorks() {
let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
let eventLoop = group.next()
let cache = SSLContextCache()
defer {
XCTAssertNoThrow(try group.syncShutdownGracefully())
cache.shutdown()
}

XCTAssertNoThrow(try cache.sslContext(tlsConfiguration: .forClient(),
eventLoop: eventLoop,
logger: HTTPClient.loggingDisabled).wait())
}

func testRequestingSSLContextAfterShutdownThrows() {
func testCacheWorks() {
let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
let eventLoop = group.next()
let cache = SSLContextCache()
defer {
XCTAssertNoThrow(try group.syncShutdownGracefully())
}

cache.shutdown()
XCTAssertThrowsError(try cache.sslContext(tlsConfiguration: .forClient(),
eventLoop: eventLoop,
logger: HTTPClient.loggingDisabled).wait())
var firstContext: NIOSSLContext?
var secondContext: NIOSSLContext?

XCTAssertNoThrow(firstContext = try cache.sslContext(tlsConfiguration: .forClient(),
eventLoop: eventLoop,
logger: HTTPClient.loggingDisabled).wait())
XCTAssertNoThrow(secondContext = try cache.sslContext(tlsConfiguration: .forClient(),
eventLoop: eventLoop,
logger: HTTPClient.loggingDisabled).wait())
XCTAssertNotNil(firstContext)
XCTAssertNotNil(secondContext)
XCTAssert(firstContext === secondContext)
}

func testCacheWorks() {
func testCacheDoesNotReturnWrongEntry() {
let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
let eventLoop = group.next()
let cache = SSLContextCache()
defer {
XCTAssertNoThrow(try group.syncShutdownGracefully())
cache.shutdown()
}

var firstContext: NIOSSLContext?
Expand All @@ -65,11 +67,13 @@ final class SSLContextCacheTests: XCTestCase {
XCTAssertNoThrow(firstContext = try cache.sslContext(tlsConfiguration: .forClient(),
eventLoop: eventLoop,
logger: HTTPClient.loggingDisabled).wait())
XCTAssertNoThrow(secondContext = try cache.sslContext(tlsConfiguration: .forClient(),

// Second one has a _different_ TLSConfiguration.
XCTAssertNoThrow(secondContext = try cache.sslContext(tlsConfiguration: .forClient(certificateVerification: .none),
eventLoop: eventLoop,
logger: HTTPClient.loggingDisabled).wait())
XCTAssertNotNil(firstContext)
XCTAssertNotNil(secondContext)
XCTAssert(firstContext === secondContext)
XCTAssert(firstContext !== secondContext)
}
}