Add Windows service host and system tray controller

service_host/ScreenJob.WindowsServiceHost/BackendProcessService.cs

@@ -0,0 +1,134 @@
+using System.Diagnostics;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace ScreenJob.WindowsServiceHost;
+
+internal sealed class BackendProcessService : BackgroundService
+{
+    private readonly ILogger<BackendProcessService> _logger;
+    private readonly ServiceOptions _options;
+    private readonly object _logLock = new();
+
+    private Process? _backendProcess;
+    private string _stdoutLogPath = string.Empty;
+    private string _stderrLogPath = string.Empty;
+
+    public BackendProcessService(ILogger<BackendProcessService> logger, ServiceOptions options)
+    {
+        _logger = logger;
+        _options = options;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        Directory.CreateDirectory(_options.LogDirectory);
+        _stdoutLogPath = Path.Combine(_options.LogDirectory, "backend-service.stdout.log");
+        _stderrLogPath = Path.Combine(_options.LogDirectory, "backend-service.stderr.log");
+
+        LogStdOut("Service host starting backend process.");
+        LogStdOut($"Script: {_options.BackendScriptPath}");
+        LogStdOut($"Working directory: {_options.WorkingDirectory}");
+
+        var powershellPath = Path.Combine(
+            Environment.GetFolderPath(Environment.SpecialFolder.Windows),
+            "System32",
+            "WindowsPowerShell",
+            "v1.0",
+            "powershell.exe");
+
+        var startInfo = new ProcessStartInfo
+        {
+            FileName = powershellPath,
+            Arguments = $"-NoProfile -ExecutionPolicy Bypass -File \"{_options.BackendScriptPath}\"",
+            WorkingDirectory = _options.WorkingDirectory,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            UseShellExecute = false,
+            CreateNoWindow = true
+        };
+
+        _backendProcess = new Process { StartInfo = startInfo };
+        if (!_backendProcess.Start())
+        {
+            throw new InvalidOperationException("Failed to start backend process.");
+        }
+
+        LogStdOut($"Backend process started with PID {_backendProcess.Id}.");
+        _logger.LogInformation("Backend process started with PID {Pid}.", _backendProcess.Id);
+
+        var stdoutPump = PumpStreamAsync(_backendProcess.StandardOutput, LogStdOut, stoppingToken);
+        var stderrPump = PumpStreamAsync(_backendProcess.StandardError, LogStdErr, stoppingToken);
+
+        try
+        {
+            await _backendProcess.WaitForExitAsync(stoppingToken);
+            LogStdOut($"Backend process exited with code {_backendProcess.ExitCode}.");
+            _logger.LogWarning("Backend process exited with code {ExitCode}.", _backendProcess.ExitCode);
+        }
+        catch (OperationCanceledException)
+        {
+            LogStdOut("Service stop requested.");
+        }
+        finally
+        {
+            await Task.WhenAll(stdoutPump, stderrPump);
+        }
+    }
+
+    public override async Task StopAsync(CancellationToken cancellationToken)
+    {
+        if (_backendProcess is { HasExited: false })
+        {
+            try
+            {
+                LogStdOut("Stopping backend process.");
+                _backendProcess.Kill(entireProcessTree: true);
+            }
+            catch (Exception ex)
+            {
+                LogStdErr($"Failed to stop backend process cleanly: {ex.Message}");
+                _logger.LogError(ex, "Failed to stop backend process cleanly.");
+            }
+        }
+
+        await base.StopAsync(cancellationToken);
+    }
+
+    private async Task PumpStreamAsync(
+        StreamReader reader,
+        Action<string> sink,
+        CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            var line = await reader.ReadLineAsync();
+            if (line is null)
+            {
+                break;
+            }
+
+            sink(line);
+        }
+    }
+
+    private void LogStdOut(string message)
+    {
+        WriteLog(_stdoutLogPath, message);
+    }
+
+    private void LogStdErr(string message)
+    {
+        WriteLog(_stderrLogPath, message);
+    }
+
+    private void WriteLog(string path, string message)
+    {
+        var stamp = DateTimeOffset.Now.ToString("yyyy-MM-dd HH:mm:ss");
+        var line = $"[{stamp}] {message}{Environment.NewLine}";
+        lock (_logLock)
+        {
+            File.AppendAllText(path, line);
+        }
+    }
+}

service_host/ScreenJob.WindowsServiceHost/Program.cs

@@ -0,0 +1,18 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using ScreenJob.WindowsServiceHost;
+
+var options = ServiceOptions.Parse(args);
+
+Host.CreateDefaultBuilder(args)
+    .UseWindowsService(serviceOptions =>
+    {
+        serviceOptions.ServiceName = "ScreenJobBackend";
+    })
+    .ConfigureServices(services =>
+    {
+        services.AddSingleton(options);
+        services.AddHostedService<BackendProcessService>();
+    })
+    .Build()
+    .Run();

service_host/ScreenJob.WindowsServiceHost/ScreenJob.WindowsServiceHost.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk.Worker">
+  <PropertyGroup>
+    <TargetFramework>net10.0-windows</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <OutputType>Exe</OutputType>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Hosting.WindowsServices" Version="10.0.0" />
+  </ItemGroup>
+</Project>

service_host/ScreenJob.WindowsServiceHost/ServiceOptions.cs

@@ -0,0 +1,77 @@
+namespace ScreenJob.WindowsServiceHost;
+
+internal sealed record ServiceOptions(
+    string BackendScriptPath,
+    string WorkingDirectory,
+    string LogDirectory)
+{
+    public static ServiceOptions Parse(string[] args)
+    {
+        var map = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+
+        for (var i = 0; i < args.Length; i++)
+        {
+            var raw = args[i];
+            if (!raw.StartsWith("--", StringComparison.Ordinal))
+            {
+                continue;
+            }
+
+            var key = raw[2..];
+            if (string.IsNullOrWhiteSpace(key))
+            {
+                continue;
+            }
+
+            if (i + 1 < args.Length && !args[i + 1].StartsWith("--", StringComparison.Ordinal))
+            {
+                map[key] = args[++i];
+            }
+            else
+            {
+                map[key] = "true";
+            }
+        }
+
+        if (!map.TryGetValue("backend-script", out var backendScript) || string.IsNullOrWhiteSpace(backendScript))
+        {
+            throw new ArgumentException("Missing required argument: --backend-script <absolute-path-to-start_backend.ps1>.");
+        }
+
+        if (!Path.IsPathRooted(backendScript))
+        {
+            throw new ArgumentException("The --backend-script value must be an absolute path.");
+        }
+
+        if (!File.Exists(backendScript))
+        {
+            throw new FileNotFoundException("Backend script not found.", backendScript);
+        }
+
+        if (!map.TryGetValue("working-dir", out var workingDir) || string.IsNullOrWhiteSpace(workingDir))
+        {
+            workingDir = Path.GetDirectoryName(backendScript)
+                ?? throw new ArgumentException("Could not resolve working directory from backend script path.");
+        }
+
+        if (!Path.IsPathRooted(workingDir))
+        {
+            throw new ArgumentException("The --working-dir value must be an absolute path.");
+        }
+
+        if (!map.TryGetValue("log-dir", out var logDir) || string.IsNullOrWhiteSpace(logDir))
+        {
+            logDir = Path.Combine(workingDir, "screenjob_runs", "service");
+        }
+
+        if (!Path.IsPathRooted(logDir))
+        {
+            throw new ArgumentException("The --log-dir value must be an absolute path.");
+        }
+
+        return new ServiceOptions(
+            Path.GetFullPath(backendScript),
+            Path.GetFullPath(workingDir),
+            Path.GetFullPath(logDir));
+    }
+}