extensions-service-discovery

name	extensions-service-discovery
description	Use when resolving service endpoints dynamically with Microsoft.Extensions.ServiceDiscovery. Covers configuration-based, DNS-based, and Aspire-integrated service resolution for HttpClient, endpoint selection strategies, and health-aware routing. USE FOR: resolving service URLs from configuration or DNS instead of hardcoding, service discovery in .NET Aspire applications, load-balanced HttpClient endpoint resolution, adding service discovery to IHttpClientFactory, health-aware service routing DO NOT USE FOR: Dapr service invocation (use dapr), direct DNS resolution without HttpClient (use System.Net.Dns), API gateway routing (use YARP or Azure API Management), Kubernetes service mesh features (use Istio or Linkerd)
license	MIT
metadata	{"displayName":"Service Discovery","author":"Tyler-R-Kendrick","version":"1.0.0"}
compatibility	claude, copilot, cursor
references	[{"title":"Service Discovery in .NET Documentation","url":"https://learn.microsoft.com/dotnet/core/extensions/service-discovery"},{"title":"Microsoft.Extensions.ServiceDiscovery NuGet Package","url":"https://www.nuget.org/packages/Microsoft.Extensions.ServiceDiscovery"},{"title":".NET Aspire GitHub Repository","url":"https://github.com/dotnet/aspire"}]

Service Discovery

Overview

Microsoft.Extensions.ServiceDiscovery provides a pluggable service endpoint resolution system for .NET applications. It resolves logical service names (like https+http://catalog-api) to actual network endpoints using configuration, DNS, or container orchestration. It integrates directly with IHttpClientFactory and is the built-in service discovery mechanism for .NET Aspire, but can also be used standalone in any .NET application.

NuGet Packages

dotnet add package Microsoft.Extensions.ServiceDiscovery
dotnet add package Microsoft.Extensions.ServiceDiscovery.Dns      # DNS SRV resolution
dotnet add package Microsoft.Extensions.ServiceDiscovery.Yarp     # YARP integration

Basic Setup

var builder = WebApplication.CreateBuilder(args);

// Add service discovery
builder.Services.AddServiceDiscovery();

// Apply to all HttpClient instances by default
builder.Services.ConfigureHttpClientDefaults(http =>
{
    http.AddServiceDiscovery();
});

var app = builder.Build();
app.Run();

Configuration-Based Resolution

Define service endpoints in appsettings.json.

{
  "Services": {
    "catalog-api": {
      "https": ["https://catalog1.example.com", "https://catalog2.example.com"],
      "http": ["http://catalog1.example.com:8080"]
    },
    "payment-service":