feat: implement zero-downtime Green/Blue deployment using local TCP proxy

2026-06-30 22:11:09 +09:00
parent 8999e51d4e
commit a84f842490
4 changed files with 203 additions and 5 deletions
@@ -0,0 +1,93 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+
+class Program
+{
+    private const string PortFile = "/home/kjh2064/taxbaik_port";
+    private static int _fallbackPort = 5003;
+
+    static async Task Main(string[] args)
+    {
+        // Allow setting fallback port via args
+        if (args.Length > 0 && int.TryParse(args[0], out var port))
+        {
+            _fallbackPort = port;
+        }
+
+        var listener = new TcpListener(IPAddress.Loopback, 5001);
+        listener.Start();
+        Console.WriteLine($"[TaxBaik Proxy] Listening on 127.0.0.1:5001 (Forwarding to target in {PortFile})");
+
+        while (true)
+        {
+            try
+            {
+                var client = await listener.AcceptTcpClientAsync();
+                _ = HandleClientAsync(client);
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine($"[TaxBaik Proxy] Accept error: {ex.Message}");
+                await Task.Delay(100);
+            }
+        }
+    }
+
+    private static int GetTargetPort()
+    {
+        try
+        {
+            if (File.Exists(PortFile))
+            {
+                var content = File.ReadAllText(PortFile).Trim();
+                if (int.TryParse(content, out var port) && port > 1024 && port < 65535)
+                {
+                    return port;
+                }
+            }
+        }
+        catch { }
+        return _fallbackPort;
+    }
+
+    private static async Task HandleClientAsync(TcpClient client)
+    {
+        client.NoDelay = true;
+        int targetPort = GetTargetPort();
+        using var backend = new TcpClient();
+        backend.NoDelay = true;
+
+        try
+        {
+            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+            await backend.ConnectAsync(IPAddress.Loopback, targetPort, cts.Token);
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"[TaxBaik Proxy] Failed to connect to backend on port {targetPort}: {ex.Message}");
+            client.Close();
+            return;
+        }
+
+        try
+        {
+            using var clientStream = client.GetStream();
+            using var backendStream = backend.GetStream();
+
+            var toBackend = clientStream.CopyToAsync(backendStream);
+            var toClient = backendStream.CopyToAsync(clientStream);
+
+            await Task.WhenAny(toBackend, toClient);
+        }
+        catch { }
+        finally
+        {
+            client.Close();
+            backend.Close();
+        }
+    }
+}