Merge pull request #473 from dotnet-maestro-bot/merge/release/2.2-to-master

[automated] Merge branch 'release/2.2' => 'master'

build/dependencies.props

@@ -31,6 +31,7 @@
     <MicrosoftExtensionsRazorViewsSourcesPackageVersion>3.0.0-alpha1-10352</MicrosoftExtensionsRazorViewsSourcesPackageVersion>
     <MicrosoftExtensionsStackTraceSourcesPackageVersion>3.0.0-alpha1-10352</MicrosoftExtensionsStackTraceSourcesPackageVersion>
     <MicrosoftExtensionsTypeNameHelperSourcesPackageVersion>3.0.0-alpha1-10352</MicrosoftExtensionsTypeNameHelperSourcesPackageVersion>
+    <MicrosoftExtensionsValueStopwatchSourcesPackageVersion>3.0.0-alpha1-10352</MicrosoftExtensionsValueStopwatchSourcesPackageVersion>
     <MicrosoftNETCoreApp20PackageVersion>2.0.9</MicrosoftNETCoreApp20PackageVersion>
     <MicrosoftNETCoreApp21PackageVersion>2.1.2</MicrosoftNETCoreApp21PackageVersion>
     <MicrosoftNETCoreApp22PackageVersion>2.2.0-preview1-26618-02</MicrosoftNETCoreApp22PackageVersion>

samples/HealthChecksSample/DBHealthStartup.cs

@@ -21,7 +21,6 @@ namespace HealthChecksSample
         {
             // Registers required services for health checks
             services.AddHealthChecks()
-
                 // Add a health check for a SQL database
                 .AddCheck(new SqlConnectionHealthCheck("MyDatabase", Configuration["ConnectionStrings:DefaultConnection"]));
         }

samples/HealthChecksSample/LivenessProbeStartup.cs

@@ -17,7 +17,6 @@ namespace HealthChecksSample
             // Registers required services for health checks
             services
                 .AddHealthChecks()
-                .AddCheck("identity", () => Task.FromResult(HealthCheckResult.Healthy()))
                 .AddCheck(new SlowDependencyHealthCheck());
         }
 
@@ -53,11 +52,8 @@ namespace HealthChecksSample
             // The liveness check uses an 'identity' health check that always returns healthy
             app.UseHealthChecks("/health/live", new HealthCheckOptions()
             {
-                // Filters the set of health checks run by this middleware
+                // Exclude all checks, just return a 200.
-                HealthCheckNames =
+                Predicate = (check) => false,
-                {
-                    "identity",
-                },
             });
 
             app.Run(async (context) =>

samples/HealthChecksSample/Program.cs

@@ -15,7 +15,7 @@ namespace HealthChecksSample
         {
             _scenarios = new Dictionary<string, Type>(StringComparer.OrdinalIgnoreCase)
             {
-                { "", typeof(BasicStartup) },
+                { "", typeof(DBHealthStartup) },
                 { "basic", typeof(BasicStartup) },
                 { "writer", typeof(CustomWriterStartup) },
                 { "liveness", typeof(LivenessProbeStartup) },
@@ -48,6 +48,8 @@ namespace HealthChecksSample
                 .UseConfiguration(config)
                 .ConfigureLogging(builder =>
                 {
+                    builder.SetMinimumLevel(LogLevel.Trace);
+                    builder.AddConfiguration(config);
                     builder.AddConsole();
                 })
                 .UseKestrel()

samples/HealthChecksSample/appsettings.json

@@ -1,5 +1,13 @@
 {
   "ConnectionStrings": {
     "DefaultConnection": "Server=(localdb)\\MSSQLLocalDB;Database=HealthCheckSample;Trusted_Connection=True;MultipleActiveResultSets=true;ConnectRetryCount=0"
+  },
+  "Logging": {
+    "LogLevel": {
+      "Default": "Debug"
+    },
+    "Console": {
+      "IncludeScopes": "true"
+    }
   }
 }

src/Microsoft.AspNetCore.Diagnostics.HealthChecks/HealthCheckMiddleware.cs

@@ -16,7 +16,6 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
         private readonly RequestDelegate _next;
         private readonly HealthCheckOptions _healthCheckOptions;
         private readonly IHealthCheckService _healthCheckService;
-        private readonly IHealthCheck[] _checks;
 
         public HealthCheckMiddleware(
             RequestDelegate next,
@@ -41,8 +40,6 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
             _next = next;
             _healthCheckOptions = healthCheckOptions.Value;
             _healthCheckService = healthCheckService;
-
-            _checks = FilterHealthChecks(_healthCheckService.Checks, healthCheckOptions.Value.HealthCheckNames);
         }
 
         /// <summary>
@@ -58,7 +55,7 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
             }
 
             // Get results
-            var result = await _healthCheckService.CheckHealthAsync(_checks, httpContext.RequestAborted);
+            var result = await _healthCheckService.CheckHealthAsync(_healthCheckOptions.Predicate, httpContext.RequestAborted);
 
             // Map status to response code - this is customizable via options. 
             if (!_healthCheckOptions.ResultStatusCodes.TryGetValue(result.Status, out var statusCode))

src/Microsoft.AspNetCore.Diagnostics.HealthChecks/HealthCheckOptions.cs

@@ -15,15 +15,19 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
     public class HealthCheckOptions
     {
         /// <summary>
-        /// Gets a set of health check names used to filter the set of health checks run.
+        /// Gets or sets a predicate that is used to filter the set of health checks executed.
         /// </summary>
         /// <remarks>
-        /// If <see cref="HealthCheckNames"/> is empty, the <see cref="HealthCheckMiddleware"/> will run all
+        /// If <see cref="Predicate"/> is <c>null</c>, the <see cref="HealthCheckMiddleware"/> will run all
         /// registered health checks - this is the default behavior. To run a subset of health checks,
-        /// add the names of the desired health checks.
+        /// provide a function that filters the set of checks.
         /// </remarks>
-        public ISet<string> HealthCheckNames { get; } = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        public Func<IHealthCheck, bool> Predicate { get; set; }
 
+        /// <summary>
+        /// Gets a dictionary mapping the <see cref="HealthCheckStatus"/> to an HTTP status code applied to the response.
+        /// This property can be used to configure the status codes returned for each status.
+        /// </summary>
         public IDictionary<HealthCheckStatus, int> ResultStatusCodes { get; } = new Dictionary<HealthCheckStatus, int>()
         {
             { HealthCheckStatus.Healthy, StatusCodes.Status200OK },

src/Microsoft.Extensions.Diagnostics.HealthChecks/HealthCheckService.cs

@@ -6,127 +6,139 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
-using Microsoft.Extensions.Logging.Abstractions;
 
 namespace Microsoft.Extensions.Diagnostics.HealthChecks
 {
-    /// <summary>
+    internal class HealthCheckService : IHealthCheckService
-    /// Default implementation of <see cref="IHealthCheckService"/>.
-    /// </summary>
-    public class HealthCheckService : IHealthCheckService
     {
+        private readonly IServiceScopeFactory _scopeFactory;
         private readonly ILogger<HealthCheckService> _logger;
 
-        /// <summary>
+        public HealthCheckService(IServiceScopeFactory scopeFactory, ILogger<HealthCheckService> logger)
-        /// A <see cref="IReadOnlyDictionary{TKey, T}"/> containing all the health checks registered in the application.
-        /// </summary>
-        /// <remarks>
-        /// The key maps to the <see cref="IHealthCheck.Name"/> property of the health check, and the value is the <see cref="IHealthCheck"/>
-        /// instance itself.
-        /// </remarks>
-        public IReadOnlyDictionary<string, IHealthCheck> Checks { get; }
-
-        /// <summary>
-        /// Constructs a <see cref="HealthCheckService"/> from the provided collection of <see cref="IHealthCheck"/> instances.
-        /// </summary>
-        /// <param name="healthChecks">The <see cref="IHealthCheck"/> instances that have been registered in the application.</param>
-        public HealthCheckService(IEnumerable<IHealthCheck> healthChecks) : this(healthChecks, NullLogger<HealthCheckService>.Instance) { }
-
-        /// <summary>
-        /// Constructs a <see cref="HealthCheckService"/> from the provided collection of <see cref="IHealthCheck"/> instances, and the provided logger.
-        /// </summary>
-        /// <param name="healthChecks">The <see cref="IHealthCheck"/> instances that have been registered in the application.</param>
-        /// <param name="logger">A <see cref="ILogger{T}"/> that can be used to log events that occur during health check operations.</param>
-        public HealthCheckService(IEnumerable<IHealthCheck> healthChecks, ILogger<HealthCheckService> logger)
         {
-            healthChecks = healthChecks ?? throw new ArgumentNullException(nameof(healthChecks));
+            _scopeFactory = scopeFactory ?? throw new ArgumentNullException(nameof(scopeFactory));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
 
-            // Scan the list for duplicate names to provide a better error if there are duplicates.
+            // We're specifically going out of our way to do this at startup time. We want to make sure you
-            var names = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            // get any kind of health-check related error as early as possible. Waiting until someone
-            var duplicates = new List<string>();
+            // actually tries to **run** health checks would be real baaaaad.
-            foreach (var check in healthChecks)
+            using (var scope = _scopeFactory.CreateScope())
             {
-                if (!names.Add(check.Name))
+                var healthChecks = scope.ServiceProvider.GetRequiredService<IEnumerable<IHealthCheck>>();
-                {
+                EnsureNoDuplicates(healthChecks);
-                    duplicates.Add(check.Name);
-                }
-            }
-
-            if (duplicates.Count > 0)
-            {
-                throw new ArgumentException($"Duplicate health checks were registered with the name(s): {string.Join(", ", duplicates)}", nameof(healthChecks));
-            }
-
-            Checks = healthChecks.ToDictionary(c => c.Name, StringComparer.OrdinalIgnoreCase);
-
-            if (_logger.IsEnabled(LogLevel.Debug))
-            {
-                foreach (var check in Checks)
-                {
-                    _logger.LogDebug("Health check '{healthCheckName}' has been registered", check.Key);
-                }
             }
         }
 
-        /// <summary>
-        /// Runs all the health checks in the application and returns the aggregated status.
-        /// </summary>
-        /// <param name="cancellationToken">A <see cref="CancellationToken"/> which can be used to cancel the health checks.</param>
-        /// <returns>
-        /// A <see cref="Task{T}"/> which will complete when all the health checks have been run,
-        /// yielding a <see cref="CompositeHealthCheckResult"/> containing the results.
-        /// </returns>
         public Task<CompositeHealthCheckResult> CheckHealthAsync(CancellationToken cancellationToken = default) =>
-            CheckHealthAsync(Checks.Values, cancellationToken);
+            CheckHealthAsync(predicate: null, cancellationToken);
-        
+
-        /// <summary>
+        public async Task<CompositeHealthCheckResult> CheckHealthAsync(
-        /// Runs the provided health checks and returns the aggregated status
+            Func<IHealthCheck, bool> predicate,
-        /// </summary>
+            CancellationToken cancellationToken = default)
-        /// <param name="checks">The <see cref="IHealthCheck"/> instances to be run.</param>
-        /// <param name="cancellationToken">A <see cref="CancellationToken"/> which can be used to cancel the health checks.</param>
-        /// <returns>
-        /// A <see cref="Task{T}"/> which will complete when all the health checks have been run,
-        /// yielding a <see cref="CompositeHealthCheckResult"/> containing the results.
-        /// </returns>
-        public async Task<CompositeHealthCheckResult> CheckHealthAsync(IEnumerable<IHealthCheck> checks, CancellationToken cancellationToken = default)
         {
-            var results = new Dictionary<string, HealthCheckResult>(Checks.Count, StringComparer.OrdinalIgnoreCase);
+            using (var scope = _scopeFactory.CreateScope())
-            foreach (var check in checks)
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                var healthChecks = scope.ServiceProvider.GetRequiredService<IEnumerable<IHealthCheck>>();
-                // If the health check does things like make Database queries using EF or backend HTTP calls,
+
-                // it may be valuable to know that logs it generates are part of a health check. So we start a scope.
+                var results = new Dictionary<string, HealthCheckResult>(StringComparer.OrdinalIgnoreCase);
-                using (_logger.BeginScope(new HealthCheckLogScope(check.Name)))
+                foreach (var healthCheck in healthChecks)
                 {
-                    HealthCheckResult result;
+                    if (predicate != null && !predicate(healthCheck))
-                    try
                     {
-                        _logger.LogTrace("Running health check: {healthCheckName}", check.Name);
+                        continue;
-                        result = await check.CheckHealthAsync(cancellationToken);
-                        _logger.LogTrace("Health check '{healthCheckName}' completed with status '{healthCheckStatus}'", check.Name, result.Status);
-                    }
-                    catch (Exception ex)
-                    {
-                        // We don't log this as an error because a health check failing shouldn't bring down the active task.
-                        _logger.LogError(ex, "Health check '{healthCheckName}' threw an unexpected exception", check.Name);
-                        result = new HealthCheckResult(HealthCheckStatus.Failed, ex, ex.Message, data: null);
                     }
 
-                    // This can only happen if the result is default(HealthCheckResult)
+                    cancellationToken.ThrowIfCancellationRequested();
-                    if (result.Status == HealthCheckStatus.Unknown)
-                    {
-                        // This is different from the case above. We throw here because a health check is doing something specifically incorrect.
-                        var exception = new InvalidOperationException($"Health check '{check.Name}' returned a result with a status of Unknown");
-                        _logger.LogError(exception, "Health check '{healthCheckName}' returned a result with a status of Unknown", check.Name);
-                        throw exception;
-                    }
 
-                    results[check.Name] = result;
+                    // If the health check does things like make Database queries using EF or backend HTTP calls,
+                    // it may be valuable to know that logs it generates are part of a health check. So we start a scope.
+                    using (_logger.BeginScope(new HealthCheckLogScope(healthCheck.Name)))
+                    {
+                        HealthCheckResult result;
+                        try
+                        {
+                            Log.HealthCheckBegin(_logger, healthCheck);
+                            var stopwatch = ValueStopwatch.StartNew();
+                            result = await healthCheck.CheckHealthAsync(cancellationToken);
+                            Log.HealthCheckEnd(_logger, healthCheck, result, stopwatch.GetElapsedTime());
+                        }
+                        catch (Exception ex)
+                        {
+                            Log.HealthCheckError(_logger, healthCheck, ex);
+                            result = new HealthCheckResult(HealthCheckStatus.Failed, ex, ex.Message, data: null);
+                        }
+
+                        // This can only happen if the result is default(HealthCheckResult)
+                        if (result.Status == HealthCheckStatus.Unknown)
+                        {
+                            // This is different from the case above. We throw here because a health check is doing something specifically incorrect.
+                            throw new InvalidOperationException($"Health check '{healthCheck.Name}' returned a result with a status of Unknown");
+                        }
+
+                        results[healthCheck.Name] = result;
+                    }
                 }
+
+                return new CompositeHealthCheckResult(results);
+            }
+        }
+
+        private static void EnsureNoDuplicates(IEnumerable<IHealthCheck> healthChecks)
+        {
+            // Scan the list for duplicate names to provide a better error if there are duplicates.
+            var duplicateNames = healthChecks
+                .GroupBy(c => c.Name, StringComparer.OrdinalIgnoreCase)
+                .Where(g => g.Count() > 1)
+                .Select(g => g.Key)
+                .ToList();
+
+            if (duplicateNames.Count > 0)
+            {
+                throw new ArgumentException($"Duplicate health checks were registered with the name(s): {string.Join(", ", duplicateNames)}", nameof(healthChecks));
+            }
+        }
+
+        private static class Log
+        {
+            public static class EventIds
+            {
+                public static readonly EventId HealthCheckBegin = new EventId(100, "HealthCheckBegin");
+                public static readonly EventId HealthCheckEnd = new EventId(101, "HealthCheckEnd");
+                public static readonly EventId HealthCheckError = new EventId(102, "HealthCheckError");
+            }
+
+            private static readonly Action<ILogger, string, Exception> _healthCheckBegin = LoggerMessage.Define<string>(
+                LogLevel.Debug,
+                EventIds.HealthCheckBegin,
+                "Running health check {HealthCheckName}");
+
+            private static readonly Action<ILogger, string, double, HealthCheckStatus, Exception> _healthCheckEnd = LoggerMessage.Define<string, double, HealthCheckStatus>(
+                LogLevel.Debug,
+                EventIds.HealthCheckEnd,
+                "Health check {HealthCheckName} completed after {ElapsedMilliseconds}ms with status {HealthCheckStatus}");
+
+            private static readonly Action<ILogger, string, Exception> _healthCheckError = LoggerMessage.Define<string>(
+                LogLevel.Error,
+                EventIds.HealthCheckError,
+                "Health check {HealthCheckName} threw an unhandled exception");
+
+            public static void HealthCheckBegin(ILogger logger, IHealthCheck healthCheck)
+            {
+                _healthCheckBegin(logger, healthCheck.Name, null);
+            }
+
+            public static void HealthCheckEnd(ILogger logger, IHealthCheck healthCheck, HealthCheckResult result, TimeSpan duration)
+            {
+                _healthCheckEnd(logger, healthCheck.Name, duration.TotalMilliseconds, result.Status, null);
+            }
+
+            public static void HealthCheckError(ILogger logger, IHealthCheck healthCheck, Exception exception)
+            {
+                _healthCheckError(logger, healthCheck.Name, exception);
             }
-            return new CompositeHealthCheckResult(results);
         }
     }
 }

src/Microsoft.Extensions.Diagnostics.HealthChecks/HealthChecksBuilderAddCheckExtensions.cs

@@ -68,7 +68,7 @@ namespace Microsoft.Extensions.DependencyInjection
         }
 
         /// <summary>
-        /// Adds a new health check with the implementation.
+        /// Adds a new health check with the provided implementation.
         /// </summary>
         /// <param name="builder">The <see cref="IHealthChecksBuilder"/> to add the check to.</param>
         /// <param name="check">An <see cref="IHealthCheck"/> implementation.</param>
@@ -88,5 +88,27 @@ namespace Microsoft.Extensions.DependencyInjection
             builder.Services.AddSingleton<IHealthCheck>(check);
             return builder;
         }
+
+        /// <summary>
+        /// Adds a new health check as a transient dependency injected service with the provided type.
+        /// </summary>
+        /// <typeparam name="T">The health check implementation type.</typeparam>
+        /// <param name="builder">The <see cref="IHealthChecksBuilder"/>.</param>
+        /// <returns>The <see cref="IHealthChecksBuilder"/>.</returns>
+        /// <remarks>
+        /// This method will register a transient service of type <see cref="IHealthCheck"/> with the 
+        /// provided implementation type <typeparamref name="T"/>. Using this method to register a health
+        /// check allows you to register a health check that depends on transient and scoped services.
+        /// </remarks>
+        public static IHealthChecksBuilder AddCheck<T>(this IHealthChecksBuilder builder) where T : class, IHealthCheck
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            builder.Services.Add(ServiceDescriptor.Transient(typeof(IHealthCheck), typeof(T)));
+            return builder;
+        }
     }
 }

src/Microsoft.Extensions.Diagnostics.HealthChecks/IHealthCheckService.cs

@@ -1,26 +1,38 @@
 // 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.Collections.Generic;
+using System;
 using System.Threading;
 using System.Threading.Tasks;
 
 namespace Microsoft.Extensions.Diagnostics.HealthChecks
 {
     /// <summary>
-    /// A service which can be used to check the status of <see cref="IHealthCheck"/> instances registered in the application.
+    /// A service which can be used to check the status of <see cref="IHealthCheck"/> instances 
+    /// registered in the application.
     /// </summary>
+    /// <remarks>
+    /// <para>
+    /// The default implementation of <see cref="IHealthCheckService"/> is registered in the dependency
+    /// injection container as a singleton service by calling 
+    /// <see cref="DependencyInjection.HealthCheckServiceCollectionExtensions.AddHealthChecks(DependencyInjection.IServiceCollection)"/>.
+    /// </para>
+    /// <para>
+    /// The <see cref="IHealthChecksBuilder"/> returned by 
+    /// <see cref="DependencyInjection.HealthCheckServiceCollectionExtensions.AddHealthChecks(DependencyInjection.IServiceCollection)"/>
+    /// provides a convenience API for registering health checks.
+    /// </para>
+    /// <para>
+    /// The default implementation of <see cref="IHealthCheckService"/> will use all services
+    /// of type <see cref="IHealthCheck"/> registered in the dependency injection container. <see cref="IHealthCheck"/>
+    /// implementations may be registered with any service lifetime. The implementation will create a scope
+    /// for each aggregate health check operation and use the scope to resolve services. The scope
+    /// created for executing health checks is controlled by the health checks service and does not
+    /// share scoped services with any other scope in the application.
+    /// </para>
+    /// </remarks>
     public interface IHealthCheckService
     {
-        /// <summary>
-        /// A <see cref="IReadOnlyDictionary{TKey, T}"/> containing all the health checks registered in the application.
-        /// </summary>
-        /// <remarks>
-        /// The key maps to the <see cref="IHealthCheck.Name"/> property of the health check, and the value is the <see cref="IHealthCheck"/>
-        /// instance itself.
-        /// </remarks>
-        IReadOnlyDictionary<string, IHealthCheck> Checks { get; }
-
         /// <summary>
         /// Runs all the health checks in the application and returns the aggregated status.
         /// </summary>
@@ -34,13 +46,15 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
         /// <summary>
         /// Runs the provided health checks and returns the aggregated status
         /// </summary>
-        /// <param name="checks">The <see cref="IHealthCheck"/> instances to be run.</param>
+        /// <param name="predicate">
+        /// A predicate that can be used to include health checks based on user-defined criteria.
+        /// </param>
         /// <param name="cancellationToken">A <see cref="CancellationToken"/> which can be used to cancel the health checks.</param>
         /// <returns>
         /// A <see cref="Task{T}"/> which will complete when all the health checks have been run,
         /// yielding a <see cref="CompositeHealthCheckResult"/> containing the results.
         /// </returns>
-        Task<CompositeHealthCheckResult> CheckHealthAsync(IEnumerable<IHealthCheck> checks,
+        Task<CompositeHealthCheckResult> CheckHealthAsync(Func<IHealthCheck, bool> predicate,
             CancellationToken cancellationToken = default);
     }
 }

src/Microsoft.Extensions.Diagnostics.HealthChecks/Microsoft.Extensions.Diagnostics.HealthChecks.csproj

@@ -14,6 +14,7 @@ Microsoft.Extensions.Diagnostics.HealthChecks.IHealthChecksBuilder
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="$(MicrosoftExtensionsDependencyInjectionAbstractionsPackageVersion)" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="$(MicrosoftExtensionsLoggingAbstractionsPackageVersion)" />
+    <PackageReference Include="Microsoft.Extensions.ValueStopwatch.Sources" Version="$(MicrosoftExtensionsValueStopwatchSourcesPackageVersion)" PrivateAssets="All" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions\Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions.csproj" />

src/Microsoft.Extensions.Diagnostics.HealthChecks/Properties/AssemblyInfo.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Microsoft.Extensions.Diagnostics.HealthChecks.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]

test/Microsoft.AspNetCore.Diagnostics.HealthChecks.Tests/HealthCheckMiddlewareTests.cs

@@ -302,11 +302,7 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
                 {
                     app.UseHealthChecks("/health", new HealthCheckOptions()
                     {
-                        HealthCheckNames =
+                        Predicate = (check) => check.Name == "Foo" || check.Name == "Baz",
-                        {
-                            "Baz",
-                            "FOO",
-                        },
                     });
                 })
                 .ConfigureServices(services =>
@@ -327,35 +323,6 @@ namespace Microsoft.AspNetCore.Diagnostics.HealthChecks
             Assert.Equal("Healthy", await response.Content.ReadAsStringAsync());
         }
 
-        [Fact]
-        public void CanFilterChecks_ThrowsForMissingCheck()
-        {
-            var builder = new WebHostBuilder()
-                .Configure(app =>
-                {
-                    app.UseHealthChecks("/health", new HealthCheckOptions()
-                    {
-                        HealthCheckNames =
-                        {
-                            "Bazzzzzz",
-                            "FOO",
-                        },
-                    });
-                })
-                .ConfigureServices(services =>
-                {
-                    services.AddHealthChecks()
-                        .AddCheck("Foo", () => Task.FromResult(HealthCheckResult.Healthy("A-ok!")))
-                        .AddCheck("Bar", () => Task.FromResult(HealthCheckResult.Unhealthy("A-ok!")))
-                        .AddCheck("Baz", () => Task.FromResult(HealthCheckResult.Healthy("A-ok!")));
-                });
-
-            var ex = Assert.Throws<InvalidOperationException>(() => new TestServer(builder));
-            Assert.Equal(
-                "The following health checks were not found: 'Bazzzzzz'. Registered health checks: 'Foo, Bar, Baz'.",
-                ex.Message);
-        }
-
         [Fact]
         public async Task CanListenOnPort_AcceptsRequest_OnSpecifiedPort()
         {

test/Microsoft.Extensions.Diagnostics.HealthChecks.Tests/HealthCheckServiceTests.cs

@@ -3,7 +3,9 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Testing;
 using Xunit;
@@ -12,40 +14,30 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
 {
     public class HealthCheckServiceTests
     {
-        [Fact]
-        public void Constructor_BuildsDictionaryOfChecks()
-        {
-            // Arrange
-            var fooCheck = new HealthCheck("Foo", _ => Task.FromResult(HealthCheckResult.Healthy()));
-            var barCheck = new HealthCheck("Bar", _ => Task.FromResult(HealthCheckResult.Healthy()));
-            var bazCheck = new HealthCheck("Baz", _ => Task.FromResult(HealthCheckResult.Healthy()));
-            var checks = new[] { fooCheck, barCheck, bazCheck };
-
-            // Act
-            var service = new HealthCheckService(checks);
-
-            // Assert
-            Assert.Same(fooCheck, service.Checks["Foo"]);
-            Assert.Same(barCheck, service.Checks["Bar"]);
-            Assert.Same(bazCheck, service.Checks["Baz"]);
-            Assert.Equal(3, service.Checks.Count);
-        }
-
         [Fact]
         public void Constructor_ThrowsUsefulExceptionForDuplicateNames()
         {
             // Arrange
-            var checks = new[]
+            //
-            {
+            // Doing this the old fashioned way so we can verify that the exception comes
-                new HealthCheck("Foo", _ => Task.FromResult(HealthCheckResult.Healthy())),
+            // from the constructor.
-                new HealthCheck("Foo", _ => Task.FromResult(HealthCheckResult.Healthy())),
+            var serviceCollection = new ServiceCollection();
-                new HealthCheck("Bar", _ => Task.FromResult(HealthCheckResult.Healthy())),
+            serviceCollection.AddLogging();
-                new HealthCheck("Baz", _ => Task.FromResult(HealthCheckResult.Healthy())),
+            serviceCollection.AddOptions();
-                new HealthCheck("Baz", _ => Task.FromResult(HealthCheckResult.Healthy())),
+            serviceCollection.AddHealthChecks()
-            };
+                .AddCheck(new HealthCheck("Foo", _ => Task.FromResult(HealthCheckResult.Healthy())))
+                .AddCheck(new HealthCheck("Foo", _ => Task.FromResult(HealthCheckResult.Healthy())))
+                .AddCheck(new HealthCheck("Bar", _ => Task.FromResult(HealthCheckResult.Healthy())))
+                .AddCheck(new HealthCheck("Baz", _ => Task.FromResult(HealthCheckResult.Healthy())))
+                .AddCheck(new HealthCheck("Baz", _ => Task.FromResult(HealthCheckResult.Healthy())));
+
+            var services = serviceCollection.BuildServiceProvider();
+
+            var scopeFactory = services.GetRequiredService<IServiceScopeFactory>();
+            var logger = services.GetRequiredService<ILogger<HealthCheckService>>();
 
             // Act
-            var exception = Assert.Throws<ArgumentException>(() => new HealthCheckService(checks));
+            var exception = Assert.Throws<ArgumentException>(() => new HealthCheckService(scopeFactory, logger));
 
             // Assert
             Assert.Equal($"Duplicate health checks were registered with the name(s): Foo, Baz{Environment.NewLine}Parameter name: healthChecks", exception.Message);
@@ -67,15 +59,11 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
                 { DataKey, DataValue }
             };
 
-            var healthyCheck = new HealthCheck("HealthyCheck", _ => Task.FromResult(HealthCheckResult.Healthy(HealthyMessage, data)));
+            var service = CreateHealthChecksService(b =>
-            var degradedCheck = new HealthCheck("DegradedCheck", _ => Task.FromResult(HealthCheckResult.Degraded(DegradedMessage)));
-            var unhealthyCheck = new HealthCheck("UnhealthyCheck", _ => Task.FromResult(HealthCheckResult.Unhealthy(UnhealthyMessage, exception)));
-
-            var service = new HealthCheckService(new[]
             {
-                healthyCheck,
+                b.AddCheck("HealthyCheck", _ => Task.FromResult(HealthCheckResult.Healthy(HealthyMessage, data)));
-                degradedCheck,
+                b.AddCheck("DegradedCheck", _ => Task.FromResult(HealthCheckResult.Degraded(DegradedMessage)));
-                unhealthyCheck,
+                b.AddCheck("UnhealthyCheck", _ => Task.FromResult(HealthCheckResult.Unhealthy(UnhealthyMessage, exception)));
             });
 
             // Act
@@ -85,7 +73,7 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
             Assert.Collection(results.Results,
                 actual =>
                 {
-                    Assert.Equal(healthyCheck.Name, actual.Key);
+                    Assert.Equal("HealthyCheck", actual.Key);
                     Assert.Equal(HealthyMessage, actual.Value.Description);
                     Assert.Equal(HealthCheckStatus.Healthy, actual.Value.Status);
                     Assert.Null(actual.Value.Exception);
@@ -97,7 +85,7 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
                 },
                 actual =>
                 {
-                    Assert.Equal(degradedCheck.Name, actual.Key);
+                    Assert.Equal("DegradedCheck", actual.Key);
                     Assert.Equal(DegradedMessage, actual.Value.Description);
                     Assert.Equal(HealthCheckStatus.Degraded, actual.Value.Status);
                     Assert.Null(actual.Value.Exception);
@@ -105,7 +93,7 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
                 },
                 actual =>
                 {
-                    Assert.Equal(unhealthyCheck.Name, actual.Key);
+                    Assert.Equal("UnhealthyCheck", actual.Key);
                     Assert.Equal(UnhealthyMessage, actual.Value.Description);
                     Assert.Equal(HealthCheckStatus.Unhealthy, actual.Value.Status);
                     Assert.Same(exception, actual.Value.Exception);
@@ -114,7 +102,7 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
         }
 
         [Fact]
-        public async Task CheckAsync_RunsProvidedChecksAndAggregatesResultsAsync()
+        public async Task CheckAsync_RunsFilteredChecksAndAggregatesResultsAsync()
         {
             const string DataKey = "Foo";
             const string DataValue = "Bar";
@@ -129,28 +117,21 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
                 { DataKey, DataValue }
             };
 
-            var healthyCheck = new HealthCheck("HealthyCheck", _ => Task.FromResult(HealthCheckResult.Healthy(HealthyMessage, data)));
+            var service = CreateHealthChecksService(b =>
-            var degradedCheck = new HealthCheck("DegradedCheck", _ => Task.FromResult(HealthCheckResult.Degraded(DegradedMessage)));
-            var unhealthyCheck = new HealthCheck("UnhealthyCheck", _ => Task.FromResult(HealthCheckResult.Unhealthy(UnhealthyMessage, exception)));
-
-            var service = new HealthCheckService(new[]
             {
-                healthyCheck,
+                b.AddCheck("HealthyCheck", _ => Task.FromResult(HealthCheckResult.Healthy(HealthyMessage, data)));
-                degradedCheck,
+                b.AddCheck("DegradedCheck", _ => Task.FromResult(HealthCheckResult.Degraded(DegradedMessage)));
-                unhealthyCheck,
+                b.AddCheck("UnhealthyCheck", _ => Task.FromResult(HealthCheckResult.Unhealthy(UnhealthyMessage, exception)));
             });
 
             // Act
-            var results = await service.CheckHealthAsync(new[]
+            var results = await service.CheckHealthAsync(c => c.Name == "HealthyCheck");
-            {
-                service.Checks["HealthyCheck"]
-            });
 
             // Assert
             Assert.Collection(results.Results,
                 actual =>
                 {
-                    Assert.Equal(healthyCheck.Name, actual.Key);
+                    Assert.Equal("HealthyCheck", actual.Key);
                     Assert.Equal(HealthyMessage, actual.Value.Description);
                     Assert.Equal(HealthCheckStatus.Healthy, actual.Value.Status);
                     Assert.Null(actual.Value.Exception);
@@ -168,11 +149,12 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
             // Arrange
             var thrownException = new InvalidOperationException("Whoops!");
             var faultedException = new InvalidOperationException("Ohnoes!");
-            var service = new HealthCheckService(new[]
+
+            var service = CreateHealthChecksService(b =>
             {
-                new HealthCheck("Throws", ct => throw thrownException),
+                b.AddCheck("Throws", ct => throw thrownException);
-                new HealthCheck("Faults", ct => Task.FromException<HealthCheckResult>(faultedException)),
+                b.AddCheck("Faults", ct => Task.FromException<HealthCheckResult>(faultedException));
-                new HealthCheck("Succeeds", ct => Task.FromResult(HealthCheckResult.Healthy())),
+                b.AddCheck("Succeeds", ct => Task.FromResult(HealthCheckResult.Healthy()));
             });
 
             // Act
@@ -223,8 +205,15 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
                     });
                 return Task.FromResult(HealthCheckResult.Healthy());
             });
+
             var loggerFactory = new TestLoggerFactory(sink, enabled: true);
-            var service = new HealthCheckService(new[] { check }, loggerFactory.CreateLogger<HealthCheckService>());
+            var service = CreateHealthChecksService(b =>
+            {
+                // Override the logger factory for testing
+                b.Services.AddSingleton<ILoggerFactory>(loggerFactory);
+
+                b.AddCheck(check);
+            });
 
             // Act
             var results = await service.CheckHealthAsync();
@@ -241,9 +230,9 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
         public async Task CheckHealthAsync_ThrowsIfCheckReturnsUnknownStatusResult()
         {
             // Arrange
-            var service = new HealthCheckService(new[]
+            var service = CreateHealthChecksService(b =>
             {
-                new HealthCheck("Kaboom", ct => Task.FromResult(default(HealthCheckResult))),
+                b.AddCheck("Kaboom", ct => Task.FromResult(default(HealthCheckResult)));
             });
 
             // Act
@@ -252,5 +241,108 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
             // Assert
             Assert.Equal("Health check 'Kaboom' returned a result with a status of Unknown", ex.Message);
         }
+
+        [Fact]
+        public async Task CheckHealthAsync_CheckCanDependOnTransientService()
+        {
+            // Arrange
+            var service = CreateHealthChecksService(b =>
+            {
+                b.Services.AddTransient<AnotherService>();
+
+                b.AddCheck<CheckWithServiceDependency>();
+            });
+
+            // Act
+            var results = await service.CheckHealthAsync();
+
+            // Assert
+            Assert.Collection(
+                results.Results,
+                actual =>
+                {
+                    Assert.Equal("Test", actual.Key);
+                    Assert.Equal(HealthCheckStatus.Healthy, actual.Value.Status);
+                });
+        }
+
+        [Fact]
+        public async Task CheckHealthAsync_CheckCanDependOnScopedService()
+        {
+            // Arrange
+            var service = CreateHealthChecksService(b =>
+            {
+                b.Services.AddScoped<AnotherService>();
+
+                b.AddCheck<CheckWithServiceDependency>();
+            });
+
+            // Act
+            var results = await service.CheckHealthAsync();
+
+            // Assert
+            Assert.Collection(
+                results.Results,
+                actual =>
+                {
+                    Assert.Equal("Test", actual.Key);
+                    Assert.Equal(HealthCheckStatus.Healthy, actual.Value.Status);
+                });
+        }
+
+        [Fact]
+        public async Task CheckHealthAsync_CheckCanDependOnSingletonService()
+        {
+            // Arrange
+            var service = CreateHealthChecksService(b =>
+            {
+                b.Services.AddSingleton<AnotherService>();
+
+                b.AddCheck<CheckWithServiceDependency>();
+            });
+
+            // Act
+            var results = await service.CheckHealthAsync();
+
+            // Assert
+            Assert.Collection(
+                results.Results,
+                actual =>
+                {
+                    Assert.Equal("Test", actual.Key);
+                    Assert.Equal(HealthCheckStatus.Healthy, actual.Value.Status);
+                });
+        }
+
+        private static HealthCheckService CreateHealthChecksService(Action<IHealthChecksBuilder> configure)
+        {
+            var services = new ServiceCollection();
+            services.AddLogging();
+            services.AddOptions();
+
+            var builder = services.AddHealthChecks();
+            if (configure != null)
+            {
+                configure(builder);
+            }
+
+            return (HealthCheckService)services.BuildServiceProvider(validateScopes: true).GetRequiredService<IHealthCheckService>();
+        }
+
+        private class AnotherService { }
+
+        private class CheckWithServiceDependency : IHealthCheck
+        {
+            public CheckWithServiceDependency(AnotherService _)
+            {
+            }
+
+            public string Name => "Test";
+
+            public Task<HealthCheckResult> CheckHealthAsync(CancellationToken cancellationToken = default)
+            {
+                return Task.FromResult(HealthCheckResult.Healthy());
+            }
+        }
     }
 }

test/Microsoft.Extensions.Diagnostics.HealthChecks.Tests/HealthChecksBuilderTests.cs

@@ -1,6 +1,8 @@
 // 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.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.Extensions.DependencyInjection;
 using Xunit;
@@ -19,12 +21,13 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
                 .AddCheck("Bar", () => Task.FromResult(HealthCheckResult.Healthy()));
 
             // Act
-            var healthCheckService = services.BuildServiceProvider().GetRequiredService<IHealthCheckService>();
+            var checks = services.BuildServiceProvider().GetRequiredService<IEnumerable<IHealthCheck>>();
 
             // Assert
-            Assert.Collection(healthCheckService.Checks,
+            Assert.Collection(
-                actual => Assert.Equal("Foo", actual.Key),
+                checks,
-                actual => Assert.Equal("Bar", actual.Key));
+                actual => Assert.Equal("Foo", actual.Name),
+                actual => Assert.Equal("Bar", actual.Name));
         }
     }
 }