Shutdown HTTPClient in deinit of Client (#31)

* Shutdown HTTPClient in deinit of Client

* Add guard, update README

* Convert httpClient param to optional, implement referencing logic

* Update README

README.md

@@ -28,7 +28,7 @@ OPENAI_ORGANIZATION="YOUR-ORGANIZATION"
 ~~~~
 ⚠️ OpenAI strongly recommends developers of client-side applications proxy requests through a separate backend service to keep their API key safe. API keys can access and manipulate customer billing, usage, and organizational data, so it's a significant risk to [expose](https://nshipster.com/secrets/) them.
 
-Create a `OpenAIKit.Client` using a httpClient and configuration.
+Create a `OpenAIKit.Client` by passing a configuration.
 
 ~~~~swift
 
@@ -42,12 +42,21 @@ var organization: String {
 
 ...
 
+let configuration = Configuration(apiKey: apiKey, organization: organization)
+
+let openAIClient = OpenAIKit.Client(configuration: configuration)
+~~~~
+
+By default, a `HTTPClient` will be internally managed by the framework. For more granular control, you may also instantiate the `OpenAIKit.Client` by passing in your own `HTTPClient`. 
+
+~~~~swift
+...
+
 let httpClient = HTTPClient(eventLoopGroupProvider: .createNew)
 defer {
     // it's important to shutdown the httpClient after all requests are done, even if one failed. See: https://github.com/swift-server/async-http-client
     try? httpClient.syncShutdown()
 }
-let configuration = Configuration(apiKey: apiKey, organization: organization)
 
 let openAIClient = OpenAIKit.Client(httpClient: httpClient, configuration: configuration)
 ~~~~

Sources/OpenAIKit/Client/Client.swift

@@ -3,7 +3,7 @@ import NIO
 import NIOHTTP1
 import Foundation
 
-public struct Client {
+public final class Client {
 
     public let audio: AudioProvider
     public let chats: ChatProvider
@@ -14,14 +14,21 @@ public struct Client {
     public let images: ImageProvider
     public let models: ModelProvider
     public let moderations: ModerationProvider
+
+    // Hold onto reference of internally created HTTPClient to perform appropriate shutdowns.
+    private let _httpClient: HTTPClient?
 
     public init(
-        httpClient: HTTPClient,
+        // If an HTTPClient is not provided, an internal one will be created, and will be shutdown after the lifecycle of the Client
+        httpClient: HTTPClient? = nil,
         configuration: Configuration
     ) {
-
+
+        // If an httpClient is provided, don't hold reference to it.
+        self._httpClient = httpClient == nil ? HTTPClient(eventLoopGroupProvider: .createNew) : nil
+
         let requestHandler = RequestHandler(
-            httpClient: httpClient,
+            httpClient: httpClient ?? _httpClient!,
             configuration: configuration
         )
 
@@ -36,5 +43,15 @@ public struct Client {
         self.moderations = ModerationProvider(requestHandler: requestHandler)
 
     }
+
+    deinit {
+        /**
+         syncShutdown() must not be called when on an EventLoop.
+         Calling syncShutdown() on any EventLoop can lead to deadlocks.
+         */
+        guard MultiThreadedEventLoopGroup.currentEventLoop == nil else { return }
+
+        try? _httpClient?.syncShutdown()
+    }
 
 }

Tests/OpenAIKitTests/OpenAIKitTests.swift

@@ -31,6 +31,17 @@ final class OpenAIKitTests: XCTestCase {
 
     }
 
+    func test_usingInternalHTTPClient() async throws {
+
+        let client = Client(
+            configuration: .init(apiKey: "YOUR-API-KEY")
+        )
+
+        let models = try await client.models.list()
+        print(models)
+
+    }
+
     func test_listModels() async throws {
         let models = try await client.models.list()
         print(models)