Add structured concurrency aware ServerBootstrap bind

Sources/NIOCore/AsyncChannel/AsyncChannel.swift

@@ -79,12 +79,11 @@ public struct NIOAsyncChannel<Inbound: Sendable, Outbound: Sendable>: Sendable {
     /// The stream of inbound messages.
     ///
     /// - Important: The `inbound` stream is a unicast `AsyncSequence` and only one iterator can be created.
-    @available(*, deprecated, message: "Use the executeThenClose scoped method instead.")
     public var inbound: NIOAsyncChannelInboundStream<Inbound> {
         self._inbound
     }
+
     /// The writer for writing outbound messages.
-    @available(*, deprecated, message: "Use the executeThenClose scoped method instead.")
     public var outbound: NIOAsyncChannelOutboundWriter<Outbound> {
         self._outbound
     }

Sources/NIOPosix/Bootstrap.swift

@@ -521,6 +521,204 @@ public final class ServerBootstrap {
 // MARK: Async bind methods
 
 extension ServerBootstrap {
+
+    /// Represents a target address or socket for binding a server socket.
+    ///
+    /// `BindTarget` provides a type-safe way to specify different types of binding targets
+    /// for server bootstraps. It supports various address types including network addresses,
+    /// Unix domain sockets, VSOCK addresses, and existing socket handles.
+    public struct BindTarget: Sendable {
+
+        enum Base {
+            case hostAndPort(host: String, port: Int)
+            case socketAddress(SocketAddress)
+            case unixDomainSocketPath(String)
+            case vsockAddress(VsockAddress)
+            case socket(NIOBSDSocket.Handle)
+        }
+
+        var base: Base
+
+        /// Creates a binding target for a hostname and port.
+        ///
+        /// This method creates a target that will resolve the hostname and bind to the
+        /// specified port. The hostname resolution follows standard system behavior
+        /// and may resolve to both IPv4 and IPv6 addresses depending on system configuration.
+        ///
+        /// - Parameters:
+        ///   - host: The hostname or IP address to bind to. Can be a domain name like 
+        ///           "localhost" or "example.com", or an IP address like "127.0.0.1" or "::1"
+        ///   - port: The port number to bind to (0-65535). Use 0 to let the system 
+        ///           choose an available port
+        public static func hostAndPort(_ host: String, _ port: Int) -> BindTarget {
+            BindTarget(base: .hostAndPort(host: host, port: port))
+        }
+
+        /// Creates a binding target for a specific socket address.
+        ///
+        /// Use this method when you have a pre-constructed ``SocketAddress`` that
+        /// specifies the exact binding location, including IPv4, IPv6, or Unix domain addresses.
+        ///
+        /// - Parameter address: The socket address to bind to
+        public static func socketAddress(_ address: SocketAddress) -> BindTarget {
+            BindTarget(base: .socketAddress(address))
+        }
+
+        /// Creates a binding target for a Unix domain socket.
+        ///
+        /// Unix domain sockets provide high-performance inter-process communication 
+        /// on the same machine using filesystem paths. The socket file will be created 
+        /// at the specified path when binding occurs.
+        ///
+        /// - Parameter path: The filesystem path for the Unix domain socket. 
+        ///                   Must be a valid filesystem path and should not exist 
+        ///                   unless cleanup is enabled in the binding operation
+        /// - Warning: The path must not exist.
+        public static func unixDomainSocketPath(_ path: String) -> BindTarget {
+            BindTarget(base: .unixDomainSocketPath(path))
+        }
+
+        /// Creates a binding target for a VSOCK address.
+        ///
+        /// VSOCK (Virtual Socket) provides communication between virtual machines and their hosts,
+        /// or between different virtual machines on the same host. This is commonly used
+        /// in virtualized environments for guest-host communication.
+        ///
+        /// - Parameter vsockAddress: The VSOCK address to bind to, containing both 
+        ///                          context ID (CID) and port number
+        /// - Note: VSOCK support depends on the underlying platform and virtualization technology
+        public static func vsockAddress(_ vsockAddress: VsockAddress) -> BindTarget {
+            BindTarget(base: .vsockAddress(vsockAddress))
+        }
+
+        /// Creates a binding target for an existing socket handle.
+        ///
+        /// This method allows you to use a pre-existing socket that has already been
+        /// created and optionally configured. This is useful for advanced scenarios where you
+        /// need custom socket setup before binding, or when integrating with external libraries.
+        ///
+        /// - Parameters:
+        ///   - handle: The existing socket handle to use. Must be a valid, open socket
+        ///            that is compatible with the intended server bootstrap type
+        /// - Note: The bootstrap will take ownership of the socket handle and will close
+        ///         it when the server shuts down
+        public static func socket(_ handle: NIOBSDSocket.Handle) -> BindTarget {
+            BindTarget(base: .socket(handle))
+        }
+    }
+
+    /// Bind the `ServerSocketChannel` to the ``BindTarget``. This method will returns once all connections that
+    /// were spawned have been closed.
+    ///
+    /// # Supporting graceful shutdown
+    ///
+    /// To support a graceful server shutdown we recommend using the `ServerQuiescingHelper` from the
+    /// SwiftNIO extras package. The `ServerQuiescingHelper` can be installed using the
+    /// ``ServerBootstrap/serverChannelInitializer`` callback.
+    ///
+    /// Below you can find the code to setup a simple TCP echo server that supports graceful server closure.
+    ///
+    /// ```swift
+    /// let quiesce = ServerQuiescingHelper(group: group)
+    /// let signalSource = DispatchSource.makeSignalSource(signal: SIGINT, queue: signalQueue)
+    /// signalSource.setEventHandler {
+    ///     signalSource.cancel()
+    ///     print("received signal, initiating shutdown which should complete after the last request finished.")
+    ///
+    ///     quiesce.initiateShutdown(promise: fullyShutdownPromise)
+    /// }
+    /// try await ServerBootstrap(group: self.eventLoopGroup)
+    ///    .serverChannelInitializer { channel in
+    ///        channel.eventLoop.makeCompletedFuture {
+    ///            try channel.pipeline.syncOperations.addHandler(quiesce.makeServerChannelHandler(channel: channel))
+    ///        }
+    ///    }
+    ///    .serverChannelOption(.socketOption(.so_reuseaddr), value: 1)
+    ///    .bind(
+    ///        target: .hostAndPort(self.host, self.port),
+    ///        childChannelInitializer: { channel in
+    ///            channel.eventLoop.makeCompletedFuture {
+    ///                try channel.pipeline.syncOperations.addHandler(ByteToMessageHandler(NewlineDelimiterCoder()))
+    ///                try channel.pipeline.syncOperations.addHandler(MessageToByteHandler(NewlineDelimiterCoder()))
+    ///
+    ///                return try NIOAsyncChannel(
+    ///                    wrappingChannelSynchronously: channel,
+    ///                    configuration: NIOAsyncChannel.Configuration(
+    ///                        inboundType: String.self,
+    ///                        outboundType: String.self
+    ///                    )
+    ///                )
+    ///            }
+    ///        }
+    ///    ) { channel in
+    ///        print("Handling new connection")
+    ///        await self.handleConnection(channel: channel)
+    ///        print("Done handling connection")
+    ///    }
+    ///
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - target: The ``BindTarget`` to use.
+    ///   - serverBackPressureStrategy: The back pressure strategy used by the server socket channel.
+    ///   - childChannelInitializer: A closure to initialize the channel. The return value of this closure is used in the `onConnection`
+    ///                              closure.
+    ///   - onceStartup: A closure that will be called once the server has been started. Use this to get access to
+    ///                  the port number, if you used port `0` in the ``BindTarget``.
+    ///   - onConnection: A closure to handle the connection. Use the channel's `inbound` property to read from
+    ///                   the connection and channel's `outbound` to write to the connection.
+    ///
+    /// - Note: The bind method respects task cancellation which will force close the server. If you want to gracefully
+    ///         shut-down use the quiescing helper approach as outlined above.
+    @available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, *)
+    public func bind<Inbound: Sendable, Outbound: Sendable>(
+        target: BindTarget,
+        serverBackPressureStrategy: NIOAsyncSequenceProducerBackPressureStrategies.HighLowWatermark? = nil,
+        childChannelInitializer: @escaping @Sendable (Channel) -> EventLoopFuture<NIOAsyncChannel<Inbound, Outbound>>,
+        onceStartup: (Channel) -> () = { _  in },
+        onConnection: @escaping @Sendable (
+            _ channel: NIOAsyncChannel<Inbound, Outbound>
+        ) async -> ()
+    ) async throws {
+        let channel = try await self.makeConnectedChannel(
+            target: target,
+            serverBackPressureStrategy: serverBackPressureStrategy,
+            childChannelInitializer: childChannelInitializer
+        )
+
+        onceStartup(channel.channel)
+
+        try await withTaskCancellationHandler {
+            try await channel.executeThenClose { inbound, outbound in
+                // we need to dance the result dance here, since we can't throw from the
+                // withDiscardingTaskGroup closure.
+                let result = await withDiscardingTaskGroup { group -> Result<Void, any Error> in
+                    do {
+                        try await channel.executeThenClose { inbound in
+                            for try await connectionChannel in inbound {
+                                group.addTask {
+                                    do {
+                                        try await connectionChannel.executeThenClose { _, _ in
+                                            await onConnection(connectionChannel)
+                                        }
+                                    } catch {
+                                        // ignore single connection failures
+                                    }
+                                }
+                            }
+                        }
+                        return .success(())
+                    } catch {
+                        return .failure(error)
+                    }
+                }
+                try result.get()
+            }
+        } onCancel: {
+            channel.channel.close(promise: nil)
+        }
+    }
+
     /// Bind the `ServerSocketChannel` to the `host` and `port` parameters.
     ///
     /// - Parameters:
@@ -622,6 +820,87 @@ extension ServerBootstrap {
         to vsockAddress: VsockAddress,
         serverBackPressureStrategy: NIOAsyncSequenceProducerBackPressureStrategies.HighLowWatermark? = nil,
         childChannelInitializer: @escaping @Sendable (Channel) -> EventLoopFuture<Output>
+    ) async throws -> NIOAsyncChannel<Output, Never> {
+        try await self._bind(
+            to: vsockAddress,
+            serverBackPressureStrategy: serverBackPressureStrategy,
+            childChannelInitializer: childChannelInitializer
+        )
+    }
+
+    /// Use the existing bound socket file descriptor.
+    ///
+    /// - Parameters:
+    ///   - socket: The _Unix file descriptor_ representing the bound stream socket.
+    ///   - cleanupExistingSocketFile: Unused.
+    ///   - serverBackPressureStrategy: The back pressure strategy used by the server socket channel.
+    ///   - childChannelInitializer: A closure to initialize the channel. The return value of this closure is returned from the `connect`
+    ///   method.
+    /// - Returns: The result of the channel initializer.
+    @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+    public func bind<Output: Sendable>(
+        _ socket: NIOBSDSocket.Handle,
+        cleanupExistingSocketFile: Bool = false,
+        serverBackPressureStrategy: NIOAsyncSequenceProducerBackPressureStrategies.HighLowWatermark? = nil,
+        childChannelInitializer: @escaping @Sendable (Channel) -> EventLoopFuture<Output>
+    ) async throws -> NIOAsyncChannel<Output, Never> {
+        try await self._bind(
+            socket,
+            serverBackPressureStrategy: serverBackPressureStrategy,
+            childChannelInitializer: childChannelInitializer
+        )
+    }
+
+    @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+    private func makeConnectedChannel<Inbound: Sendable, Outbound: Sendable>(
+        target: BindTarget,
+        serverBackPressureStrategy: NIOAsyncSequenceProducerBackPressureStrategies.HighLowWatermark? = nil,
+        childChannelInitializer: @escaping @Sendable (Channel) -> EventLoopFuture<NIOAsyncChannel<Inbound, Outbound>>
+    ) async throws -> NIOAsyncChannel<NIOAsyncChannel<Inbound, Outbound>, Never> {
+        switch target.base {
+        case .hostAndPort(let host, let port):
+            try await self.bind(
+                to: try SocketAddress.makeAddressResolvingHost(host, port: port),
+                serverBackPressureStrategy: serverBackPressureStrategy,
+                childChannelInitializer: childChannelInitializer
+            )
+
+        case .unixDomainSocketPath(let unixDomainSocketPath):
+            try await self.bind(
+                to: try SocketAddress(unixDomainSocketPath: unixDomainSocketPath),
+                serverBackPressureStrategy: serverBackPressureStrategy,
+                childChannelInitializer: childChannelInitializer
+            )
+
+        case .socketAddress(let address):
+            try await self.bind(
+                to: address,
+                serverBackPressureStrategy: serverBackPressureStrategy,
+                childChannelInitializer: childChannelInitializer
+            )
+
+        case .vsockAddress(let vsockAddress):
+            try await self._bind(
+                to: vsockAddress,
+                serverBackPressureStrategy: serverBackPressureStrategy,
+                childChannelInitializer: childChannelInitializer
+            )
+
+        case .socket(let handle):
+            try await self._bind(
+                handle,
+                serverBackPressureStrategy: serverBackPressureStrategy,
+                childChannelInitializer: childChannelInitializer
+            )
+        }
+    }
+
+
+    @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+    private func _bind<Output: Sendable>(
+        to vsockAddress: VsockAddress,
+        serverBackPressureStrategy: NIOAsyncSequenceProducerBackPressureStrategies.HighLowWatermark? = nil,
+        childChannelInitializer: @escaping @Sendable (Channel) -> EventLoopFuture<Output>
     ) async throws -> NIOAsyncChannel<Output, Never> {
         func makeChannel(
             _ eventLoop: SelectableEventLoop,
@@ -652,19 +931,9 @@ extension ServerBootstrap {
         }.get()
     }
 
-    /// Use the existing bound socket file descriptor.
-    ///
-    /// - Parameters:
-    ///   - socket: The _Unix file descriptor_ representing the bound stream socket.
-    ///   - cleanupExistingSocketFile: Unused.
-    ///   - serverBackPressureStrategy: The back pressure strategy used by the server socket channel.
-    ///   - childChannelInitializer: A closure to initialize the channel. The return value of this closure is returned from the `connect`
-    ///   method.
-    /// - Returns: The result of the channel initializer.
     @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
-    public func bind<Output: Sendable>(
+    private func _bind<Output: Sendable>(
         _ socket: NIOBSDSocket.Handle,
-        cleanupExistingSocketFile: Bool = false,
         serverBackPressureStrategy: NIOAsyncSequenceProducerBackPressureStrategies.HighLowWatermark? = nil,
         childChannelInitializer: @escaping @Sendable (Channel) -> EventLoopFuture<Output>
     ) async throws -> NIOAsyncChannel<Output, Never> {