Add friendly error message for when healthchecks services not registered (#8146)

src/Middleware/HealthChecks/src/Builder/HealthCheckApplicationBuilderExtensions.cs

@@ -4,6 +4,8 @@
 using System;
 using Microsoft.AspNetCore.Diagnostics.HealthChecks;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
 using Microsoft.Extensions.Options;
 
 namespace Microsoft.AspNetCore.Builder
@@ -225,6 +227,14 @@ namespace Microsoft.AspNetCore.Builder
 
         private static void UseHealthChecksCore(IApplicationBuilder app, PathString path, int? port, object[] args)
         {
+            if (app.ApplicationServices.GetService(typeof(HealthCheckService)) == null)
+            {
+                throw new InvalidOperationException(Resources.FormatUnableToFindServices(
+                    nameof(IServiceCollection),
+                    nameof(HealthCheckServiceCollectionExtensions.AddHealthChecks),
+                    "ConfigureServices(...)"));
+            }
+
             // NOTE: we explicitly don't use Map here because it's really common for multiple health
             // check middleware to overlap in paths. Ex: `/health`, `/health/detailed` - this is order
             // sensititive with Map, and it's really surprising to people.

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

@@ -6,6 +6,8 @@ using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Diagnostics.HealthChecks;
 using Microsoft.Extensions.Options;
 using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Builder
 {
@@ -93,6 +95,14 @@ namespace Microsoft.AspNetCore.Builder
 
         private static IEndpointConventionBuilder MapHealthChecksCore(IEndpointRouteBuilder builder, string pattern, HealthCheckOptions options, string displayName)
         {
+            if (builder.ServiceProvider.GetService(typeof(HealthCheckService)) == null)
+            {
+                throw new InvalidOperationException(Resources.FormatUnableToFindServices(
+                    nameof(IServiceCollection),
+                    nameof(HealthCheckServiceCollectionExtensions.AddHealthChecks),
+                    "ConfigureServices(...)"));
+            }
+
             var args = options != null ? new[] { Options.Create(options) } : Array.Empty<object>();
 
             var pipeline = builder.CreateApplicationBuilder()

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

@@ -24,4 +24,11 @@
     <Reference Include="Microsoft.Net.Http.Headers" />
   </ItemGroup>
 
+  <ItemGroup>
+    <EmbeddedResource Update="Resources.resx">
+      <Generator>ResXFileCodeGenerator</Generator>
+      <LastGenOutput>Resources.Designer.cs</LastGenOutput>
+    </EmbeddedResource>
+  </ItemGroup>
+
 </Project>

src/Middleware/HealthChecks/src/Properties/Resources.Designer.cs

@@ -0,0 +1,44 @@
+// <auto-generated />
+namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
+{
+    using System.Globalization;
+    using System.Reflection;
+    using System.Resources;
+
+    internal static class Resources
+    {
+        private static readonly ResourceManager _resourceManager
+            = new ResourceManager("Microsoft.AspNetCore.Diagnostics.HealthChecks.Resources", typeof(Resources).GetTypeInfo().Assembly);
+
+        /// <summary>
+        /// Unable to find the required services. Please add all the required services by calling '{0}.{1}' inside the call to '{2}' in the application startup code.
+        /// </summary>
+        internal static string UnableToFindServices
+        {
+            get => GetString("UnableToFindServices");
+        }
+
+        /// <summary>
+        /// Unable to find the required services. Please add all the required services by calling '{0}.{1}' inside the call to '{2}' in the application startup code.
+        /// </summary>
+        internal static string FormatUnableToFindServices(object p0, object p1, object p2)
+            => string.Format(CultureInfo.CurrentCulture, GetString("UnableToFindServices"), p0, p1, p2);
+
+        private static string GetString(string name, params string[] formatterNames)
+        {
+            var value = _resourceManager.GetString(name);
+
+            System.Diagnostics.Debug.Assert(value != null);
+
+            if (formatterNames != null)
+            {
+                for (var i = 0; i < formatterNames.Length; i++)
+                {
+                    value = value.Replace("{" + formatterNames[i] + "}", "{" + i + "}");
+                }
+            }
+
+            return value;
+        }
+    }
+}

src/Middleware/HealthChecks/src/Resources.resx

@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="UnableToFindServices" xml:space="preserve">
+    <value>Unable to find the required services. Please add all the required services by calling '{0}.{1}' inside the call to '{2}' in the application startup code.</value>
+  </data>
+</root>

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

@@ -18,6 +18,31 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
 {
     public class HealthCheckEndpointRouteBuilderExtensionsTest
     {
+        [Fact]
+        public void ThrowFriendlyErrorWhenServicesNotRegistered()
+        {
+            var builder = new WebHostBuilder()
+                .Configure(app =>
+                {
+                    app.UseRouting(routes =>
+                    {
+                        routes.MapHealthChecks("/healthz");
+                    });
+                })
+                .ConfigureServices(services =>
+                {
+                    services.AddRouting();
+                });
+
+            var ex = Assert.Throws<InvalidOperationException>(() => new TestServer(builder));
+
+            Assert.Equal(
+                "Unable to find the required services. Please add all the required services by calling " +
+                "'IServiceCollection.AddHealthChecks' inside the call to 'ConfigureServices(...)' " +
+                "in the application startup code.",
+                ex.Message);
+        }
+
         [Fact]
         public async Task MapHealthChecks_ReturnsOk()
         {

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

@@ -19,6 +19,24 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
 {
     public class HealthCheckMiddlewareTests
     {
+        [Fact]
+        public void ThrowFriendlyErrorWhenServicesNotRegistered()
+        {
+            var builder = new WebHostBuilder()
+                .Configure(app =>
+                {
+                    app.UseHealthChecks("/health");
+                });
+
+            var ex = Assert.Throws<InvalidOperationException>(() => new TestServer(builder));
+
+            Assert.Equal(
+                "Unable to find the required services. Please add all the required services by calling " +
+                "'IServiceCollection.AddHealthChecks' inside the call to 'ConfigureServices(...)' " +
+                "in the application startup code.",
+                ex.Message);
+        }
+
         [Fact] // Matches based on '.Map'
         public async Task IgnoresRequestThatDoesNotMatchPath()
         {