Removed unnecessary locks.

Author: fabianfett

Sources/AWSLambdaRuntimeCore/HTTPClient.swift

@@ -25,7 +25,7 @@ internal final class HTTPClient {
     private let targetHost: String
 
     private var state = State.disconnected
-    private let executing = NIOAtomic.makeAtomic(value: false)
+    private var executing = false
 
     init(eventLoop: EventLoop, configuration: Lambda.Configuration.RuntimeEngine) {
         self.eventLoop = eventLoop
@@ -50,7 +50,7 @@ internal final class HTTPClient {
 
     /// cancels the current request if there is one
     func cancel() {
-        guard self.executing.exchange(with: true) else {
+        guard self.executing else {
             // there is no request running. nothing to cancel
             return
         }
@@ -64,7 +64,10 @@ internal final class HTTPClient {
 
     // TODO: cap reconnect attempt
     private func execute(_ request: Request, validate: Bool = true) -> EventLoopFuture<Response> {
-        precondition(!validate || self.executing.compareAndExchange(expected: false, desired: true), "expecting single request at a time")
+        if validate {
+            precondition(self.executing == false)
+            self.executing = true
+        }
 
         switch self.state {
         case .disconnected:
@@ -80,7 +83,8 @@ internal final class HTTPClient {
 
             let promise = channel.eventLoop.makePromise(of: Response.self)
             promise.futureResult.whenComplete { _ in
-                precondition(self.executing.compareAndExchange(expected: true, desired: false), "invalid execution state")
+                precondition(self.executing == true)
+                self.executing = false
             }
             let wrapper = HTTPRequestWrapper(request: request, promise: promise)
             channel.writeAndFlush(wrapper).cascadeFailure(to: promise)

Sources/AWSLambdaRuntimeCore/LambdaLifecycle.swift

@@ -18,6 +18,8 @@ import NIOConcurrencyHelpers
 
 extension Lambda {
     /// `Lifecycle` manages the Lambda process lifecycle.
+    ///
+    /// - note: It is intended to be used within a single `EventLoop`. For this reason this class is not thread safe.
     public final class Lifecycle {
         private let eventLoop: EventLoop
         private let shutdownPromise: EventLoopPromise<Int>
@@ -82,8 +84,7 @@ extension Lambda {
         // MARK: -  Private
 
         #if DEBUG
-        /// Begin the `Lifecycle` shutdown.
-        /// Only needed for debugging purposes.
+        /// Begin the `Lifecycle` shutdown. Only needed for debugging purposes, hence behind a `DEBUG` flag.
         public func shutdown() {
             // make this method thread safe by dispatching onto the eventloop
             self.eventLoop.execute {