Add health checks routing extensions (#5127)

Author: JamesNK

src/Middleware/HealthChecks/src/Builder/HealthCheckEndpointRouteBuilderExtensions.cs

@@ -0,0 +1,71 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Diagnostics.HealthChecks;
+using Microsoft.Extensions.Options;
+using Microsoft.AspNetCore.Routing;
+
+namespace Microsoft.AspNetCore.Builder
+{
+    /// <summary>
+    /// Provides extension methods for <see cref="IEndpointRouteBuilder"/> to add health checks.
+    /// </summary>
+    public static class HealthCheckEndpointRouteBuilderExtensions
+    {
+        /// <summary>
+        /// Adds a health checks endpoint to the <see cref="IEndpointRouteBuilder"/> with the specified template.
+        /// </summary>
+        /// <param name="builder">The <see cref="IEndpointRouteBuilder"/> to add the health checks endpoint to.</param>
+        /// <param name="pattern">The URL pattern of the health checks endpoint.</param>
+        /// <returns>A convention builder for the health checks endpoint.</returns>
+        public static IEndpointConventionBuilder MapHealthChecks(
+           this IEndpointRouteBuilder builder,
+           string pattern)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            return MapHealthChecksCore(builder, pattern, null);
+        }
+
+        /// <summary>
+        /// Adds a health checks endpoint to the <see cref="IEndpointRouteBuilder"/> with the specified template and options.
+        /// </summary>
+        /// <param name="builder">The <see cref="IEndpointRouteBuilder"/> to add the health checks endpoint to.</param>
+        /// <param name="pattern">The URL pattern of the health checks endpoint.</param>
+        /// <param name="options">A <see cref="HealthCheckOptions"/> used to configure the health checks.</param>
+        /// <returns>A convention builder for the health checks endpoint.</returns>
+        public static IEndpointConventionBuilder MapHealthChecks(
+           this IEndpointRouteBuilder builder,
+           string pattern,
+           HealthCheckOptions options)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            if (options == null)
+            {
+                throw new ArgumentNullException(nameof(options));
+            }
+
+            return MapHealthChecksCore(builder, pattern, options);
+        }
+
+        private static IEndpointConventionBuilder MapHealthChecksCore(IEndpointRouteBuilder builder, string pattern, HealthCheckOptions options)
+        {
+            var args = options != null ? new[] { Options.Create(options) } : Array.Empty<object>();
+
+            var pipeline = builder.CreateApplicationBuilder()
+               .UseMiddleware<HealthCheckMiddleware>(args)
+               .Build();
+
+            return builder.Map(pattern, "Health checks", pipeline);
+        }
+    }
+}

src/Middleware/HealthChecks/src/Microsoft.AspNetCore.Diagnostics.HealthChecks.csproj

@@ -17,6 +17,7 @@
 
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Http.Abstractions" />
+    <Reference Include="Microsoft.AspNetCore.Routing" />
     <Reference Include="Microsoft.Extensions.Diagnostics.HealthChecks" />
     <Reference Include="Microsoft.Extensions.Options" />
     <Reference Include="Microsoft.Net.Http.Headers" />

src/Middleware/HealthChecks/test/UnitTests/HealthCheckEndpointRouteBuilderExtensionsTest.cs

@@ -0,0 +1,86 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.TestHost;
+using Moq;
+using Xunit;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
+{
+    public class HealthCheckEndpointRouteBuilderExtensionsTest
+    {
+        [Fact]
+        public async Task MapHealthChecks_ReturnsOk()
+        {
+            // Arrange
+            var builder = new WebHostBuilder()
+                .Configure(app =>
+                {
+                    app.UseRouting(routes =>
+                    {
+                        routes.MapHealthChecks("/healthz");
+                    });
+                })
+                .ConfigureServices(services =>
+                {
+                    services.AddRouting();
+                    services.AddHealthChecks();
+                });
+            var server = new TestServer(builder);
+            var client = server.CreateClient();
+
+            // Act
+            var response = await client.GetAsync("/healthz");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+            Assert.Equal("text/plain", response.Content.Headers.ContentType.ToString());
+            Assert.Equal("Healthy", await response.Content.ReadAsStringAsync());
+        }
+
+        [Fact]
+        public async Task MapHealthChecks_WithOptions_ReturnsOk()
+        {
+            // Arrange
+            var builder = new WebHostBuilder()
+                .Configure(app =>
+                {
+                    app.UseRouting(routes =>
+                    {
+                        routes.MapHealthChecks("/healthz", new HealthCheckOptions
+                        {
+                            ResponseWriter = async (context, report) =>
+                            {
+                                context.Response.ContentType = "text/plain";
+                                await context.Response.WriteAsync("Custom!");
+                            }
+                        });
+                    });
+                })
+                .ConfigureServices(services =>
+                {
+                    services.AddRouting();
+                    services.AddHealthChecks();
+                });
+            var server = new TestServer(builder);
+            var client = server.CreateClient();
+
+            // Act
+            var response = await client.GetAsync("/healthz");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+            Assert.Equal("text/plain", response.Content.Headers.ContentType.ToString());
+            Assert.Equal("Custom!", await response.Content.ReadAsStringAsync());
+        }
+    }
+}