Add Go Build Tags Support (#733)

* Add Go Build Tags Support

I updated GolangAppHostingExtension to support specifying Go build tags
to be used when building and running Go applications. Go build tags can
be used to include or exclude files from the build process based On
specific conditions. For example, when using Aspire for development, a
Go developer may use a build tag to enable special code for
OpenTelemetry instrumentation or enable debugging features.

Closes #730

* Revise Command-Line Building

I revised the way that I was building the command line for the `go run`
command based on review recommendations. The new approach should improve
readability of the code.

Author: mfcollins3

src/CommunityToolkit.Aspire.Hosting.Golang/GolangAppHostingExtension.cs

@@ -15,23 +15,35 @@ public static class GolangAppHostingExtension
     /// <param name="name">The name of the resource.</param>
     /// <param name="workingDirectory">The working directory to use for the command. If null, the working directory of the current process is used.</param>
     /// <param name="args">The optinal arguments to be passed to the executable when it is started.</param>
+    /// <param name="buildTags">The optional build tags to be used when building the Golang application.</param>
     /// <returns>A reference to the <see cref="IResourceBuilder{T}"/>.</returns>
-    public static IResourceBuilder<GolangAppExecutableResource> AddGolangApp(this IDistributedApplicationBuilder builder, [ResourceName] string name, string workingDirectory, string[]? args = null)
+    public static IResourceBuilder<GolangAppExecutableResource> AddGolangApp(this IDistributedApplicationBuilder builder, [ResourceName] string name, string workingDirectory, string[]? args = null, string[]? buildTags = null)
     {
         ArgumentNullException.ThrowIfNull(builder, nameof(builder));
         ArgumentException.ThrowIfNullOrWhiteSpace(name, nameof(name));
         ArgumentException.ThrowIfNullOrWhiteSpace(workingDirectory, nameof(workingDirectory));
 
-        string[] allArgs = args is { Length: > 0 }
-            ? ["run", ".", .. args]
-            : ["run", ".",];
+        var allArgs = new List<string> { "run" };
+
+        if (buildTags is { Length: > 0 })
+        {
+            allArgs.Add("-tags");
+            allArgs.Add(string.Join(",", buildTags));
+        }
+
+        allArgs.Add(".");
+
+        if (args is { Length: > 0 })
+        {
+            allArgs.AddRange(args);
+        }
 
         workingDirectory = Path.Combine(builder.AppHostDirectory, workingDirectory).NormalizePathForCurrentPlatform();
         var resource = new GolangAppExecutableResource(name, workingDirectory);
 
         return builder.AddResource(resource)
                       .WithGolangDefaults()
-                      .WithArgs(allArgs);
+                      .WithArgs(allArgs.ToArray());
     }
 
     private static IResourceBuilder<GolangAppExecutableResource> WithGolangDefaults(

tests/CommunityToolkit.Aspire.Hosting.Golang.Tests/ResourceCreationTests.cs

@@ -21,4 +21,41 @@ public void DefaultGolangApp()
 
         Assert.Equal("go", resource.Command);
     }
+
+    [Fact]
+    public async Task GolangAppWithBuildTagsAsync()
+    {
+        var builder = DistributedApplication.CreateBuilder();
+
+        builder.AddGolangApp("golang", "../../examples/golang/gin-api", buildTags: ["dev"]);
+
+        using var app = builder.Build();
+
+        var appModel = app.Services.GetRequiredService<DistributedApplicationModel>();
+
+        var resource = appModel.Resources.OfType<GolangAppExecutableResource>().SingleOrDefault();
+
+        Assert.NotNull(resource);
+
+        var args = await resource.GetArgumentValuesAsync();
+        Assert.Collection(
+            args,
+            arg =>
+            {
+                Assert.Equal("run", arg);
+            },
+            arg =>
+            {
+                Assert.Equal("-tags", arg);
+            },
+            arg =>
+            {
+                Assert.Equal("dev", arg);
+            },
+            arg =>
+            {
+                Assert.Equal(".", arg);
+            }
+        );
+    }
 }