App Updater

NexusMods.App.sln

@@ -123,6 +123,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Networking.Downlo
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Abstractions", "src\NexusMods.Abstractions\NexusMods.Abstractions.csproj", "{1E20E979-5F04-44FD-BE07-54B6686ECB13}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Updater", "src\NexusMods.Updater\NexusMods.Updater.csproj", "{39563B8C-E034-401E-AC97-47FD570759C0}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Updater.Tests", "tests\NexusMods.Updater.Tests\NexusMods.Updater.Tests.csproj", "{1A9F310A-BA79-44C0-95E8-A3A66BD691AC}"
+EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Games.Generic.Tests", "tests\Games\NexusMods.Games.Generic.Tests\NexusMods.Games.Generic.Tests.csproj", "{AA95B93F-23AC-46D5-83B3-2E7AE4BD309C}"
 EndProject
 Global
@@ -303,10 +307,18 @@ Global
 		{1E20E979-5F04-44FD-BE07-54B6686ECB13}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{1E20E979-5F04-44FD-BE07-54B6686ECB13}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1E20E979-5F04-44FD-BE07-54B6686ECB13}.Release|Any CPU.Build.0 = Release|Any CPU
+		{39563B8C-E034-401E-AC97-47FD570759C0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{39563B8C-E034-401E-AC97-47FD570759C0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{39563B8C-E034-401E-AC97-47FD570759C0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{39563B8C-E034-401E-AC97-47FD570759C0}.Release|Any CPU.Build.0 = Release|Any CPU
 		{AA95B93F-23AC-46D5-83B3-2E7AE4BD309C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{AA95B93F-23AC-46D5-83B3-2E7AE4BD309C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{AA95B93F-23AC-46D5-83B3-2E7AE4BD309C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{AA95B93F-23AC-46D5-83B3-2E7AE4BD309C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1A9F310A-BA79-44C0-95E8-A3A66BD691AC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1A9F310A-BA79-44C0-95E8-A3A66BD691AC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1A9F310A-BA79-44C0-95E8-A3A66BD691AC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1A9F310A-BA79-44C0-95E8-A3A66BD691AC}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -361,6 +373,8 @@ Global
 		{09B037AB-07BB-4154-95FD-6EA2E55C4568} = {897C4198-884F-448A-B0B0-C2A6D971EAE0}
 		{1E20E979-5F04-44FD-BE07-54B6686ECB13} = {E7BAE287-D505-4D6D-A090-665A64309B2D}
 		{AA95B93F-23AC-46D5-83B3-2E7AE4BD309C} = {05B06AC1-7F2B-492F-983E-5BC63CDBF20D}
+		{39563B8C-E034-401E-AC97-47FD570759C0} = {E7BAE287-D505-4D6D-A090-665A64309B2D}
+		{1A9F310A-BA79-44C0-95E8-A3A66BD691AC} = {52AF9D62-7D5B-4AD0-BA12-86F2AA67428B}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {9F9F8352-34DD-42C0-8564-EE9AF34A3501}

docs/design-explanations/0003-updater-design.md

@@ -0,0 +1,61 @@
+# Application Updater
+
+## Problem
+The application needs a way to update itself, preferably without a lot of
+user interaction
+
+The issue is that on Windows and perhaps other platforms an executable cannot
+be overwritten while it is running. This means that the application cannot
+simply download a new version and restart itself. Instead we need to have
+a multi-step process.
+
+## Design Goals
+
+* Remain as simple as possible, we don't want to pull in a lot of dependencies
+* The application is rather small, so we don't need to worry about any sort of delta
+  patching
+* It would be nice to not need a separate launcher application as then we have an A->B->A issue
+  where we need an updater to update the updater
+* It would be nice to be able to download an update while the app is running, and then let the user
+  know that we will update the code during next time the app launches
+* We should never stop the users from using the app just to run an update
+* We should recover from failed updates
+* We can't update when the CLI is running, so we need to not attempt to run updates when multiple
+  processes are running.
+* Make it as OS agnostic as possible, so we don't need to write a different updater for each OS
+
+
+
+## Implementation
+
+The solution to this problem is to download updates into a `_update` folder, inside the main
+application folder. When the application starts it looks for this folder, and if there is a pending
+update, the app relaunches itself with special flag, but runs the executable in the `_update` folder.
+This command then reads the current folder and copies its contents into parent folder. This means
+that all the logic is contained inside the application itself, and yet still allows for updates.
+
+
+## Code Flow
+
+### On CLI start
+* Look for a `__update__` folder, and see if `UPDATE_READY` exists as a file in that folder
+* If it does, log a message saying there's a pending update, the contents of the `UPDATE_READY` file contains the new version
+
+### On normal app start
+* If any other process is running with the same process name as the current process, exit the update routine
+* If the `__update__` folder exists, but does not contain the `UPDATE_READY` file, then delete the folder, and continue a normal launch
+* If the `__update__` folder exists, and contains a `UPDATE_READY` file, launch the app with the `copy-app-to-folder` command,
+  passing in the current app folder, and the current app process ID. Then exit the app.
+
+### During normal app operation
+* Read the list of versions available from github
+* If the current version is not the latest version, extract the latest version to the `__update__` folder
+* Create a `UPDATE_READY` file in the `__update__` folder, and write the new version number to it
+* If the current version is the latest, cache the latest version for 6 hours (so future app restarts don't ping github)
+* Sleep for 6 hours
+
+### If the app is run with `copy-app-to-folder`
+* Wait for the parent process to exit
+* Copy everything in the current folder to the parent folder
+* Delete the `UPDATE_READY` file
+* Launch the process in the parent, and exit

src/NexusMods.Abstractions/CLI/AVerb.cs

@@ -76,3 +76,26 @@ public interface AVerb<in T1, in T2, in T3> : IVerb
     public Task<int> Run(T1 a, T2 b, T3 c, CancellationToken token);
 }
 
+/// <summary>
+/// Abstract class for a verb that takes four arguments
+/// </summary>
+/// <typeparam name="T1"></typeparam>
+/// <typeparam name="T2"></typeparam>
+/// <typeparam name="T3"></typeparam>
+/// <typeparam name="T4"></typeparam>
+public interface AVerb<in T1, in T2, in T3, in T4> : IVerb
+{
+    Delegate IVerb.Delegate => Run;
+
+    /// <summary>
+    /// Runs the verb
+    /// </summary>
+    /// <param name="a"></param>
+    /// <param name="b"></param>
+    /// <param name="c"></param>
+    /// <param name="d"></param>
+    /// <param name="token"></param>
+    /// <returns></returns>
+    public Task<int> Run(T1 a, T2 b, T3 c, T4 d, CancellationToken token);
+}
+

src/NexusMods.App.UI/Windows/MainWindow.axaml.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
 using Avalonia;
@@ -18,6 +19,8 @@ public MainWindow()
         this.AttachDevTools();
         #endif
 
+        Title = "Nexus Mods App - v" + Process.GetCurrentProcess().MainModule?.FileVersionInfo?.ProductVersion ?? "Unknown";
+
         this.WhenActivated(disposables =>
         {
             this.OneWayBind(ViewModel, vm => vm.TopBar, v => v.TopBar.ViewModel)

src/NexusMods.App/CLI/Renderers/Spectre.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using NexusMods.Abstractions.CLI;
 using NexusMods.DataModel.RateLimiting;
 using Spectre.Console;
@@ -20,7 +21,9 @@ public Spectre(IEnumerable<IResource> resources)
     public string Name => "console";
     public void RenderBanner()
     {
-        //AnsiConsole.Write(new FigletText("NexusMods.App") {Color = NexusColor});
+        AnsiConsole.Write(new FigletText("NexusMods.App") {Color = NexusColor});
+        var version = Process.GetCurrentProcess().MainModule?.FileVersionInfo?.ProductVersion;
+        AnsiConsole.Write(new Text($"v: {version}\n", new Style(NexusColor)));
     }
 
     public async Task<T> WithProgress<T>(CancellationToken token, Func<Task<T>> f, bool showSize = true)
@@ -129,6 +132,9 @@ public async Task Render<T>(T o)
             case Abstractions.CLI.DataOutputs.Table t:
                 await RenderTable(t);
                 break;
+            case string s:
+                AnsiConsole.MarkupLine(s);
+                break;
             default:
                 throw new NotImplementedException();
         }

src/NexusMods.App/NexusMods.App.csproj

@@ -20,6 +20,7 @@
         <ProjectReference Include="..\Networking\NexusMods.Networking.NexusWebApi\NexusMods.Networking.NexusWebApi.csproj" />
         <ProjectReference Include="..\NexusMods.App.UI\NexusMods.App.UI.csproj" />
         <ProjectReference Include="..\NexusMods.CLI\NexusMods.CLI.csproj" />
+        <ProjectReference Include="..\NexusMods.Updater\NexusMods.Updater.csproj" />
     </ItemGroup>
 
     <ItemGroup>

src/NexusMods.App/Program.cs

@@ -12,6 +12,7 @@
 using NexusMods.CLI;
 using NexusMods.Common;
 using NexusMods.Paths;
+using NexusMods.Updater;
 using NLog.Extensions.Logging;
 using NLog.Targets;
 using ReactiveUI;
@@ -25,7 +26,7 @@ public class Program
     [STAThread]
     public static async Task<int> Main(string[] args)
     {
-        var host = BuildHost();
+        var host = BuildHost(args.Length == 0);
 
         _logger = host.Services.GetRequiredService<ILogger<Program>>();
         TaskScheduler.UnobservedTaskException += (_, e) =>
@@ -59,11 +60,18 @@ public static async Task<int> Main(string[] args)
 
         // Start listeners only available in GUI mode
         host.Services.GetRequiredService<NxmRpcListener>();
+
+        if (Environment.GetCommandLineArgs().Length != 0)
+        {
+            var updater = host.Services.GetRequiredService<UpdaterService>();
+            await updater.Startup();
+        }
+
         Startup.Main(host.Services, args);
         return 0;
     }
 
-    public static IHost BuildHost()
+    public static IHost BuildHost(bool isGui = true)
     {
         // I'm not 100% sure how to wire this up to cleanly pass settings
         // to ConfigureLogging; since the DI container isn't built until the host is.
@@ -80,6 +88,7 @@ public static IHost BuildHost()
                 config = JsonSerializer.Deserialize<AppConfig>(configJson)!;
                 config.Sanitize();
                 services.AddSingleton(config);
+                services.AddUpdater();
                 services.AddApp(config).Validate();
             })
             .ConfigureLogging((_, builder) => AddLogging(builder, config.LoggingSettings))

src/NexusMods.App/Services.cs

@@ -33,7 +33,7 @@ public static IServiceCollection AddRenderers(this IServiceCollection services)
         services.AddScoped<IRenderer, Json>();
         return services;
     }
-    
+
     public static IServiceCollection AddListeners(this IServiceCollection services)
     {
         services.AddSingleton<NxmRpcListener>();

src/NexusMods.Common/FakeProcessFactory.cs

@@ -1,25 +1,28 @@
 using System.Buffers;
+using System.Diagnostics;
 using System.Text;
 using CliWrap;
 
 namespace NexusMods.Common;
 
-internal class FakeProcessFactory : IProcessFactory
+public class FakeProcessFactory : IProcessFactory
 {
     private readonly int _exitCode;
 
     public Action<Command>? Callback { get; set; }
     public Func<Command, Task>? AsyncCallback { get; set; }
 
     public string? StandardOutput { get; set; }
     public string? StandardError { get; set; }
 
+    public List<Command> Commands { get; } = new();
+
     public FakeProcessFactory(int exitCode)
     {
         _exitCode = exitCode;
     }
 
     public async Task<CommandResult> ExecuteAsync(Command command,
         CancellationToken cancellationToken = default)
     {
         Callback?.Invoke(command);
@@ -47,6 +50,25 @@
             DateTimeOffset.Now));
     }
 
+    /// <inheritdoc />
+    public Process? ExecuteAndDetach(Command command)
+    {
+        throw new ExecuteAndDetatchException(command);
+    }
+
+    /// <summary>
+    /// Thrown when <see cref="IProcessFactory.ExecuteAndDetach"/> is called. Used to test that the
+    /// correct command was passed to the factory.
+    /// </summary>
+    public class ExecuteAndDetatchException : Exception
+    {
+        public Command Command { get; }
+        public ExecuteAndDetatchException(Command command) : base("Executed command and detached from it")
+        {
+            Command = command;
+        }
+    }
+
     private static async Task WriteStringToPipe(string text, PipeTarget pipe, CancellationToken cancellationToken = default)
     {
         var bytes = ArrayPool<byte>.Shared.Rent(Encoding.UTF8.GetMaxByteCount(text.Length));

src/NexusMods.Common/IProcessFactory.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using CliWrap;
 
 namespace NexusMods.Common;
@@ -13,4 +14,14 @@ public interface IProcessFactory
     /// <param name="command">The command to execute.</param>
     /// <param name="cancellationToken">Allows you to cancel the task, killing the process prematurely.</param>
     Task<CommandResult> ExecuteAsync(Command command, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Executes the given command that starts the process, but remains detached from it in such a way
+    /// that the process will continue to run even if the parent process is killed.
+    ///
+    /// Returns null if the process could not be started.
+    /// </summary>
+    /// <param name="command"></param>
+    /// <returns></returns>
+    Process? ExecuteAndDetach(Command command);
 }

src/NexusMods.Common/ProcessFactory.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using CliWrap;
 
 namespace NexusMods.Common;
@@ -13,4 +14,16 @@ public async Task<CommandResult> ExecuteAsync(Command command,
     {
         return await command.ExecuteAsync(cancellationToken);
     }
+
+    /// <inheritdoc />
+    public Process? ExecuteAndDetach(Command command)
+    {
+        var info = new ProcessStartInfo(command.TargetFilePath)
+        {
+            Arguments = command.Arguments,
+            WorkingDirectory = command.WorkingDirPath,
+
+        };
+        return Process.Start(info);
+    }
 }

src/NexusMods.Updater/Constants.cs

@@ -0,0 +1,11 @@
+using NexusMods.Paths;
+
+namespace NexusMods.Updater;
+
+public static class Constants
+{
+    public static RelativePath UpdateMarkerFile = new("UPDATE_READY");
+    public static RelativePath UpdateFolder = new("__update__");
+    public static RelativePath UpdateExecutable = new("NexusMods.App.exe");
+
+}

src/NexusMods.Updater/DTOs/Asset.cs

@@ -0,0 +1,16 @@
+using System.Text.Json.Serialization;
+
+namespace NexusMods.Updater.DTOs;
+
+public class Asset
+{
+    [JsonPropertyName("browser_download_url")]
+    public Uri BrowserDownloadUrl { get; set; } = new("https://nexusmods.com/");
+
+    [JsonPropertyName("name")] public string Name { get; set; } = "";
+
+
+    [JsonPropertyName("size")]
+    public long Size { get; set; }
+}
+

src/NexusMods.Updater/DTOs/Release.cs

@@ -0,0 +1,9 @@
+using System.Text.Json.Serialization;
+
+namespace NexusMods.Updater.DTOs;
+
+public class Release
+{
+    [JsonPropertyName("tag_name")] public string Tag { get; set; } = "";
+    [JsonPropertyName("assets")] public Asset[] Assets { get; set; } = Array.Empty<Asset>();
+}

src/NexusMods.Updater/DownloadSources/Github.cs

@@ -0,0 +1,31 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using NexusMods.Updater.DTOs;
+
+namespace NexusMods.Updater.DownloadSources;
+
+public class Github
+{
+    private readonly HttpClient _client;
+
+    public Github(HttpClient client)
+    {
+        _client = client;
+    }
+
+    public async Task<Release?> GetLatestRelease(string owner, string repo)
+    {
+        var releases = await GetReleases(owner, repo);
+        return releases.FirstOrDefault();
+    }
+
+    private async Task<Release[]> GetReleases(string owner, string repo)
+    {
+        var url = $"https://github.com/repos/{owner}/{repo}/releases";
+        var request = new HttpRequestMessage(HttpMethod.Get, url);
+        request.Headers.Add("User-Agent", "NexusMods.Updater");
+        var response = await _client.SendAsync(request);
+        var json = await response.Content.ReadAsStringAsync();
+        return JsonSerializer.Deserialize<Release[]>(json)!;
+    }
+}