Use HostUrl to contextually resolve the aspire dashboard url within…

… a container.

src/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector/OpenTelemetryCollectorExtensions.cs

@@ -36,12 +36,10 @@ public static IResourceBuilder<OpenTelemetryCollectorResource> AddOpenTelemetryC
 
         var isHttpsEnabled = !settings.ForceNonSecureReceiver && url.StartsWith("https", StringComparison.OrdinalIgnoreCase);
 
-        var dashboardOtlpEndpoint = ReplaceLocalhostWithContainerHost(url, builder.Configuration);
-
         var resource = new OpenTelemetryCollectorResource(name);
         var resourceBuilder = builder.AddResource(resource)
             .WithImage(settings.CollectorImage, settings.CollectorTag)
-            .WithEnvironment("ASPIRE_ENDPOINT", dashboardOtlpEndpoint)
+            .WithEnvironment("ASPIRE_ENDPOINT", new HostUrl(url))
             .WithEnvironment("ASPIRE_API_KEY", builder.Configuration[DashboardOtlpApiKeyVariableName]);
 
         if (settings.EnableGrpcEndpoint)
@@ -87,15 +85,6 @@ public static IResourceBuilder<OpenTelemetryCollectorResource> WithAppForwarding
         return builder;
     }
 
-    private static string ReplaceLocalhostWithContainerHost(string value, IConfiguration configuration)
-    {
-        var hostName = configuration["AppHost:ContainerHostname"] ?? "host.docker.internal";
-
-        return value.Replace("localhost", hostName, StringComparison.OrdinalIgnoreCase)
-                    .Replace("127.0.0.1", hostName)
-                    .Replace("[::1]", hostName);
-    }
-
     /// <summary>
     /// Adds a config file to the collector
     /// </summary>

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

@@ -173,7 +173,9 @@ public void ContainerHasAspireEnvironmentVariables()
 
         Assert.Contains("ASPIRE_ENDPOINT", context.EnvironmentVariables.Keys);
         Assert.Contains("ASPIRE_API_KEY", context.EnvironmentVariables.Keys);
-        Assert.Equal("http://host.docker.internal:18889", context.EnvironmentVariables["ASPIRE_ENDPOINT"]);
+
+        var url = Assert.IsType<HostUrl>(context.EnvironmentVariables["ASPIRE_ENDPOINT"]);
+        Assert.Equal("http://localhost:18889", url.Url);
         Assert.NotNull(context.EnvironmentVariables["ASPIRE_API_KEY"]);
     }