Use EventLoop provided by SwiftNIO's MultiThreadedEventLoopGroup.singleton

Package.swift

@@ -14,8 +14,8 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-atomics.git", from: "1.1.0"),
-        .package(url: "https://github.com/apple/swift-nio.git", from: "2.52.0"),
-        .package(url: "https://github.com/apple/swift-nio-transport-services.git", from: "1.16.0"),
+        .package(url: "https://github.com/apple/swift-nio.git", from: "2.58.0"),
+        .package(url: "https://github.com/apple/swift-nio-transport-services.git", from: "1.18.0"),
         .package(url: "https://github.com/apple/swift-nio-ssl.git", from: "2.23.1"),
         .package(url: "https://github.com/apple/swift-crypto.git", "1.0.0" ..< "3.0.0"),
         .package(url: "https://github.com/apple/swift-metrics.git", from: "2.0.0"),

README.md

@@ -67,19 +67,7 @@ let config = PostgresConnection.Configuration(
 )
 ```
 
-A connection must be created on a SwiftNIO `EventLoop`. In most server use cases, an 
-`EventLoopGroup` is created at app startup and closed during app shutdown.
-
-```swift
-import NIOPosix
-
-let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
-
-// Much later
-try await eventLoopGroup.shutdownGracefully()
-```
-
-A [`Logger`] is also required.
+To create a connection we need a [`Logger`], that is used to log connection background events.
 
 ```swift
 import Logging
@@ -91,10 +79,8 @@ Now we can put it together:
 
 ```swift
 import PostgresNIO
-import NIOPosix
 import Logging
 
-let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
 let logger = Logger(label: "postgres-logger")
 
 let config = PostgresConnection.Configuration(
@@ -107,17 +93,13 @@ let config = PostgresConnection.Configuration(
 )
 
 let connection = try await PostgresConnection.connect(
-  on: eventLoopGroup.next(),
   configuration: config,
   id: 1,
   logger: logger
 )
 
 // Close your connection once done
 try await connection.close()
-
-// Shutdown the EventLoopGroup, once all connections are closed.
-try await eventLoopGroup.shutdownGracefully()
 ```
 
 #### Querying

Sources/PostgresNIO/Connection/PostgresConnection.swift

@@ -360,13 +360,13 @@ extension PostgresConnection {
     /// Creates a new connection to a Postgres server.
     ///
     /// - Parameters:
-    ///   - eventLoop: The `EventLoop` the request shall be created on
+    ///   - eventLoop: The `EventLoop` the connection shall be created on.
     ///   - configuration: A ``Configuration`` that shall be used for the connection
     ///   - connectionID: An `Int` id, used for metadata logging
     ///   - logger: A logger to log background events into
     /// - Returns: An established  ``PostgresConnection`` asynchronously that can be used to run queries.
     public static func connect(
-        on eventLoop: EventLoop,
+        on eventLoop: EventLoop = PostgresConnection.defaultEventLoopGroup.any(),
         configuration: PostgresConnection.Configuration,
         id connectionID: ID,
         logger: Logger
@@ -661,3 +661,20 @@ extension EventLoopFuture {
         }
     }
 }
+
+extension PostgresConnection {
+    /// Returns the default `EventLoopGroup` singleton, automatically selecting the best for the platform.
+    ///
+    /// This will select the concrete `EventLoopGroup` depending which platform this is running on.
+    public static var defaultEventLoopGroup: EventLoopGroup {
+#if canImport(Network)
+        if #available(OSX 10.14, iOS 12.0, tvOS 12.0, watchOS 6.0, *) {
+            return NIOTSEventLoopGroup.singleton
+        } else {
+            return MultiThreadedEventLoopGroup.singleton
+        }
+#else
+        return MultiThreadedEventLoopGroup.singleton
+#endif
+    }
+}