fix: send coder User-Agent on all deployment requests

CoderSdk/Agent/AgentApiClient.cs

@@ -44,7 +44,7 @@ public AgentApiClient(Uri baseUrl)
     {
         if (baseUrl.PathAndQuery != "/")
             throw new ArgumentException($"Base URL '{baseUrl}' must not contain a path", nameof(baseUrl));
-        _httpClient = new JsonHttpClient(baseUrl, AgentApiJsonContext.Default);
+        _httpClient = new JsonHttpClient(baseUrl, AgentApiJsonContext.Default, CoderComponent.Desktop);
     }
 
     private async Task<TResponse> SendRequestNoBodyAsync<TResponse>(HttpMethod method, string path,

CoderSdk/Coder/CoderApiClient.cs

@@ -67,18 +67,20 @@ public partial class CoderApiClient : ICoderApiClient
 
     private readonly JsonHttpClient _httpClient;
 
-    public CoderApiClient(string baseUrl) : this(new Uri(baseUrl, UriKind.Absolute))
+    public CoderApiClient(string baseUrl, CoderComponent component = CoderComponent.Desktop)
+        : this(new Uri(baseUrl, UriKind.Absolute), component)
     {
     }
 
-    public CoderApiClient(Uri baseUrl)
+    public CoderApiClient(Uri baseUrl, CoderComponent component = CoderComponent.Desktop)
     {
         if (baseUrl.PathAndQuery != "/")
             throw new ArgumentException($"Base URL '{baseUrl}' must not contain a path", nameof(baseUrl));
-        _httpClient = new JsonHttpClient(baseUrl, CoderApiJsonContext.Default);
+        _httpClient = new JsonHttpClient(baseUrl, CoderApiJsonContext.Default, component);
     }
 
-    public CoderApiClient(string baseUrl, string token) : this(baseUrl)
+    public CoderApiClient(string baseUrl, string token, CoderComponent component = CoderComponent.Desktop)
+        : this(baseUrl, component)
     {
         SetSessionToken(token);
     }

CoderSdk/JsonHttpClient.cs

@@ -25,7 +25,7 @@ internal class JsonHttpClient
     // TODO: allow users to add headers
     private readonly HttpClient _httpClient = new();
 
-    public JsonHttpClient(Uri baseUri, IJsonTypeInfoResolver typeResolver)
+    public JsonHttpClient(Uri baseUri, IJsonTypeInfoResolver typeResolver, CoderComponent component)
     {
         _jsonOptions = new JsonSerializerOptions
         {
@@ -36,6 +36,7 @@ public JsonHttpClient(Uri baseUri, IJsonTypeInfoResolver typeResolver)
         };
         _jsonOptions.Converters.Add(new JsonStringEnumConverter(new SnakeCaseNamingPolicy(), false));
         _httpClient.BaseAddress = baseUri;
+        _httpClient.DefaultRequestHeaders.UserAgent.ParseAdd(UserAgent.Build(component));
     }
 
     public void RemoveHeader(string key)

CoderSdk/UserAgent.cs

@@ -0,0 +1,81 @@
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+namespace Coder.Desktop.CoderSdk;
+
+/// <summary>
+///     Identifies which Coder Desktop process is making a request.
+/// </summary>
+public enum CoderComponent
+{
+    /// <summary>The tray application.</summary>
+    Desktop,
+
+    /// <summary>The privileged background service that manages the VPN tunnel.</summary>
+    Core,
+}
+
+/// <summary>
+///     Builds the User-Agent header value sent by every Coder Desktop HTTP client.
+/// </summary>
+public static class UserAgent
+{
+    private const string DesktopToken = "coder-desktop";
+    private const string CoreToken = "coder-desktop-core";
+
+    private const string UnknownVersion = "0.0.0";
+    private const string UnknownPlatform = "unknown";
+
+    /// <summary>
+    ///     Builds a User-Agent for <paramref name="component" />, taking the version from the entry assembly.
+    /// </summary>
+    public static string Build(CoderComponent component)
+    {
+        return Build(component, Assembly.GetEntryAssembly());
+    }
+
+    /// <summary>
+    ///     Builds a User-Agent for component, taking the version from versionSource. Prefer the single-argument overload outside of tests.
+    /// </summary>
+    public static string Build(CoderComponent component, Assembly? versionSource)
+    {
+        return $"{TokenOf(component)}/{VersionOf(versionSource)} ({Goos()}/{Goarch()})";
+    }
+
+    private static string TokenOf(CoderComponent component)
+    {
+        return component switch
+        {
+            CoderComponent.Desktop => DesktopToken,
+            CoderComponent.Core => CoreToken,
+            _ => throw new ArgumentOutOfRangeException(nameof(component), component, null),
+        };
+    }
+
+    private static string VersionOf(Assembly? assembly)
+    {
+        // Assembly versions are four-part (0.8.4.0); the User-Agent reports the three-part release.
+        var version = assembly?.GetName().Version;
+        return version is null ? UnknownVersion : $"{version.Major}.{version.Minor}.{version.Build}";
+    }
+
+    // Platform names deliberately match Go's GOOS/GOARCH Desktop clients, the CLI and the vpn-daemon
+    private static string Goos()
+    {
+        if (OperatingSystem.IsWindows()) return "windows";
+        if (OperatingSystem.IsMacOS()) return "darwin";
+        if (OperatingSystem.IsLinux()) return "linux";
+        return UnknownPlatform;
+    }
+
+    private static string Goarch()
+    {
+        return RuntimeInformation.ProcessArchitecture switch
+        {
+            Architecture.X64 => "amd64",
+            Architecture.Arm => "arm",
+            Architecture.Arm64 => "arm64",
+            _ => UnknownPlatform,
+        };
+    }
+}

Tests.CoderSdk/UserAgentTest.cs

@@ -0,0 +1,55 @@
+using System.Reflection;
+using System.Text.RegularExpressions;
+using Coder.Desktop.CoderSdk;
+
+namespace Coder.Desktop.Tests.CoderSdk;
+
+[TestFixture]
+public class UserAgentTest
+{
+    // Every Coder client is expected to match this, so operators can allowlist the token set. Keep it in
+    // sync with the Coder CLI (cli/root.go) and the macOS and Linux Desktop clients.
+    private static readonly Regex Grammar = new(
+        @"^coder-(cli|desktop|desktop-core|vpn-daemon)/\d+\.\d+\.\d+ \((windows|darwin|linux|unknown)/(386|amd64|arm|arm64|unknown)(; .+)?\)$");
+
+    [Test(Description = "Matches the shared User-Agent grammar")]
+    [TestCase(CoderComponent.Desktop)]
+    [TestCase(CoderComponent.Core)]
+    public void MatchesGrammar(CoderComponent component)
+    {
+        Assert.That(UserAgent.Build(component), Does.Match(Grammar));
+    }
+
+    [Test(Description = "Each component reports its own token")]
+    public void ComponentTokens()
+    {
+        Assert.That(UserAgent.Build(CoderComponent.Desktop), Does.StartWith("coder-desktop/"));
+        Assert.That(UserAgent.Build(CoderComponent.Core), Does.StartWith("coder-desktop-core/"));
+    }
+
+    [Test(Description = "Four-part assembly versions are trimmed to the three-part release version")]
+    public void TrimsAssemblyVersion()
+    {
+        var assembly = Assembly.GetExecutingAssembly();
+        var version = assembly.GetName().Version;
+        Assert.That(version, Is.Not.Null, "test assembly has no version");
+
+        var ua = UserAgent.Build(CoderComponent.Desktop, assembly);
+        Assert.That(ua, Does.Match(Grammar));
+        Assert.That(ua, Does.StartWith($"coder-desktop/{version!.Major}.{version.Minor}.{version.Build} ("));
+    }
+
+    [Test(Description = "An unversioned assembly still produces a well-formed User-Agent")]
+    public void UnknownVersion()
+    {
+        var ua = UserAgent.Build(CoderComponent.Desktop, null);
+        Assert.That(ua, Does.Match(Grammar));
+        Assert.That(ua, Does.StartWith("coder-desktop/0.0.0 ("));
+    }
+
+    [Test(Description = "Unrecognized components are rejected rather than silently mislabeled")]
+    public void UnknownComponent()
+    {
+        Assert.Throws<ArgumentOutOfRangeException>(() => UserAgent.Build((CoderComponent)(-1)));
+    }
+}

Tests.Vpn.Service/DownloaderTest.cs

@@ -2,6 +2,7 @@
 using System.Security.Cryptography;
 using System.Security.Cryptography.X509Certificates;
 using System.Text;
+using Coder.Desktop.CoderSdk;
 using Coder.Desktop.Vpn.Service;
 using Microsoft.Extensions.Logging.Abstractions;
 
@@ -377,6 +378,45 @@ public async Task WithHeaders(CancellationToken ct)
         await dlTask.Task;
     }
 
+    [Test(Description = "Download identifies itself with a User-Agent")]
+    [CancelAfter(30_000)]
+    public async Task WithUserAgent(CancellationToken ct)
+    {
+        // Deployments behind a WAF reject requests with no User-Agent, which previously made the
+        // tunnel binary undownloadable. See coder-desktop-windows#176.
+        using var httpServer = new TestHttpServer(ctx =>
+        {
+            Assert.That(ctx.Request.UserAgent, Is.EqualTo(UserAgent.Build(CoderComponent.Core)));
+            ctx.Response.StatusCode = 200;
+        });
+        var url = new Uri(httpServer.BaseUrl + "/test");
+        var destPath = Path.Combine(_tempDir, "test");
+
+        var manager = new Downloader(NullLogger<Downloader>.Instance);
+        var req = new HttpRequestMessage(HttpMethod.Get, url);
+        var dlTask = await manager.StartDownloadAsync(req, destPath, NullDownloadValidator.Instance, ct);
+        await dlTask.Task;
+    }
+
+    [Test(Description = "A caller-supplied User-Agent overrides the default")]
+    [CancelAfter(30_000)]
+    public async Task WithUserAgentOverride(CancellationToken ct)
+    {
+        using var httpServer = new TestHttpServer(ctx =>
+        {
+            Assert.That(ctx.Request.UserAgent, Is.EqualTo("custom-agent/1.2.3"));
+            ctx.Response.StatusCode = 200;
+        });
+        var url = new Uri(httpServer.BaseUrl + "/test");
+        var destPath = Path.Combine(_tempDir, "test");
+
+        var manager = new Downloader(NullLogger<Downloader>.Instance);
+        var req = new HttpRequestMessage(HttpMethod.Get, url);
+        req.Headers.UserAgent.ParseAdd("custom-agent/1.2.3");
+        var dlTask = await manager.StartDownloadAsync(req, destPath, NullDownloadValidator.Instance, ct);
+        await dlTask.Task;
+    }
+
     [Test(Description = "Perform a download against an existing identical file")]
     [CancelAfter(30_000)]
     public async Task DownloadExisting(CancellationToken ct)

Vpn.Service/Downloader.cs

@@ -6,6 +6,7 @@
 using System.Runtime.ExceptionServices;
 using System.Security.Cryptography;
 using System.Security.Cryptography.X509Certificates;
+using Coder.Desktop.CoderSdk;
 using Coder.Desktop.Vpn.Utilities;
 using Microsoft.Extensions.Logging;
 using Microsoft.Security.Extensions;
@@ -348,10 +349,16 @@ public class DownloadTask
     private const int BufferSize = 64 * 1024;
     private const string XOriginalContentLengthHeader = "X-Original-Content-Length"; // overrides Content-Length if available
 
-    private static readonly HttpClient HttpClient = new(new HttpClientHandler
+    private static readonly HttpClient HttpClient = new Func<HttpClient>(() =>
     {
-        AutomaticDecompression = DecompressionMethods.All,
-    });
+        var client = new HttpClient(new HttpClientHandler
+        {
+            AutomaticDecompression = DecompressionMethods.All,
+        });
+        client.DefaultRequestHeaders.UserAgent.ParseAdd(UserAgent.Build(CoderComponent.Core));
+        return client;
+    })();
+
     private readonly string _destinationDirectory;
 
     private readonly ILogger _logger;

Vpn.Service/Manager.cs

@@ -1,4 +1,5 @@
 using System.Runtime.InteropServices;
+using Coder.Desktop.CoderSdk;
 using Coder.Desktop.CoderSdk.Coder;
 using Coder.Desktop.Vpn.Proto;
 using Coder.Desktop.Vpn.Utilities;
@@ -440,7 +441,7 @@ private static string SystemArchitecture()
     private async ValueTask<ServerVersion> CheckServerVersionAndCredentials(string baseUrl, string apiToken,
         CancellationToken ct = default)
     {
-        var client = new CoderApiClient(baseUrl, apiToken);
+        var client = new CoderApiClient(baseUrl, apiToken, CoderComponent.Core);
 
         var buildInfo = await client.GetBuildInfo(ct);
         _logger.LogInformation("Fetched server version '{ServerVersion}'", buildInfo.Version);