fix(link): actually bound the server connect with a timeout [CI]

backend/fleet/src/Fleet.Link/FleetLink.cs

@@ -64,6 +64,9 @@ public sealed class FleetLinkOptions
     /// <summary>Optional reason for an orderly client shutdown, so the server can distinguish updates from service stops.</summary>
     public Func<string>? ShutdownReason { get; init; }
 
+    /// <summary>连上服务器的整个过程（TCP、TLS、升级）最多等多久；卡住就放弃，由外层退避重试。</summary>
+    public TimeSpan ConnectTimeout { get; init; } = TimeSpan.FromSeconds(20);
+
     public TimeSpan HeartbeatInterval { get; init; } = TimeSpan.FromSeconds(10);
 
     public int MaxFrameBytes { get; init; } = 16 << 20;
@@ -96,7 +99,7 @@ public sealed class FleetLink
     private readonly INodeLog _log;
     private volatile RpcSession<LinkContext>? _session;
     private volatile bool _stopped;
-    private static readonly TimeSpan s_connectTimeout = TimeSpan.FromSeconds(20);
+
     private static readonly TimeSpan s_tcpTimeout = TimeSpan.FromSeconds(4);
     private int _failedConnects;
 
@@ -179,7 +182,7 @@ public sealed class FleetLink
         using var handler = new SocketsHttpHandler { ConnectCallback = (context, token) => ConnectTcpAsync(context, attempt, token) };
         using var invoker = new HttpMessageInvoker(handler, disposeHandler: false);
         using CancellationTokenSource timeout = CancellationTokenSource.CreateLinkedTokenSource(ct);
-        timeout.CancelAfter(s_connectTimeout);
+        timeout.CancelAfter(_options.ConnectTimeout);
         try
         {
             await socket.ConnectAsync(uri, invoker, timeout.Token);
@@ -233,7 +236,7 @@ public sealed class FleetLink
         socket.Options.KeepAliveInterval = TimeSpan.FromSeconds(15);
         socket.Options.KeepAliveTimeout = TimeSpan.FromSeconds(20); // 对端 20 秒没有回 Pong 就判定连接已死
         var builder = new UriBuilder(_options.Server) { Scheme = _options.Server.Scheme == "https" ? "wss" : "ws", Path = RpcPath };
-        await socket.ConnectAsync(builder.Uri, ct);
+        await ConnectAsync(socket, builder.Uri, ct);
         await using var transport = new SecureTransport(new WsTransport(socket, _options.MaxFrameBytes));
 
         string? failure = await AuthenticateAsync(transport, ct);

backend/fleet/tests/Fleet.Tests/LinkConnectTimeoutTests.cs

@@ -0,0 +1,98 @@
+using System.Net;
+using System.Net.Sockets;
+using Fleet.Core;
+using Fleet.Identity;
+using Fleet.Link;
+using Fleet.Rpc;
+
+namespace Fleet.Tests;
+
+/// <summary>面板那头只接住连接、什么都不回（线路把握手吞了、代理卡住）：节点要在限定时间内放弃这次连接重试，而不是一直等着。</summary>
+public sealed class LinkConnectTimeoutTests
+{
+    [Fact]
+    public async Task ASilentServer_IsGivenUp_AfterTheConnectTimeout_AndRetried()
+    {
+        using var listener = new TcpListener(IPAddress.Loopback, 0);
+        listener.Start();
+        var accepted = new List<TcpClient>();
+        using var acceptLoop = new CancellationTokenSource();
+        Task accepting = Task.Run(async () =>
+        {
+            try
+            {
+                while (true)
+                {
+                    accepted.Add(await listener.AcceptTcpClientAsync(acceptLoop.Token));
+                }
+            }
+            catch (OperationCanceledException)
+            {
+                // 测试结束
+            }
+        });
+
+        var options = new FleetLinkOptions
+        {
+            Server = new Uri($"http://127.0.0.1:{((IPEndPoint)listener.LocalEndpoint).Port}"),
+            Identity = NodeIdentity.Generate(),
+            NodeId = new NodeId("prb_test"),
+            ConnectTimeout = TimeSpan.FromMilliseconds(500),
+            Backoff = new Backoff(TimeSpan.FromMilliseconds(10), TimeSpan.FromMilliseconds(50)),
+        };
+        var router = new RpcRouter<LinkContext>(RpcSide.Node, FleetMethodTable.Table);
+        var link = new FleetLink(options, router, [], new Outbox(1 << 16), TimeProvider.System, new SilentLog());
+        var reasons = new List<string>();
+        link.OnDisconnected = reason =>
+        {
+            lock (reasons)
+            {
+                reasons.Add(reason);
+            }
+        };
+
+        using var stop = new CancellationTokenSource();
+        Task running = link.RunAsync(stop.Token);
+        try
+        {
+            using var deadline = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+            while (true)
+            {
+                lock (reasons)
+                {
+                    if (reasons.Count >= 2)
+                    {
+                        break;
+                    }
+                }
+
+                await Task.Delay(50, deadline.Token);
+            }
+
+            lock (reasons)
+            {
+                Assert.All(reasons, reason => Assert.Contains("timed out", reason, StringComparison.OrdinalIgnoreCase));
+            }
+
+            Assert.True(accepted.Count >= 2, "the second attempt connects again");
+        }
+        finally
+        {
+            await stop.CancelAsync();
+            await running;
+            await acceptLoop.CancelAsync();
+            await accepting;
+            foreach (TcpClient client in accepted)
+            {
+                client.Dispose();
+            }
+        }
+    }
+
+    private sealed class SilentLog : INodeLog
+    {
+        public void Write(NodeLogLevel level, string message, params (string Key, object? Value)[] fields)
+        {
+        }
+    }
+}