Added MongoDb heathcheck

HealthChecks.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26228.9
+VisualStudioVersion = 15.0.27004.2002
 MinimumVisualStudioVersion = 15.0.26228.4
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "samples", "samples", "{E05DCF88-F916-4B61-A5DC-A8344C9E2429}"
 EndProject
@@ -25,6 +25,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNet.HealthChec
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SampleHealthChecker.AspNet", "samples\SampleHealthChecker.AspNet\SampleHealthChecker.AspNet.csproj", "{33FB5967-62C7-4230-B515-780EF63F748E}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.Extensions.HealthChecks.MongoDb", "src\Microsoft.Extensions.HealthChecks.MongoDb\Microsoft.Extensions.HealthChecks.MongoDb.csproj", "{17689B4B-7361-417F-B87D-0C8162E0F0C8}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -63,6 +65,10 @@ Global
 		{33FB5967-62C7-4230-B515-780EF63F748E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{33FB5967-62C7-4230-B515-780EF63F748E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{33FB5967-62C7-4230-B515-780EF63F748E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{17689B4B-7361-417F-B87D-0C8162E0F0C8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{17689B4B-7361-417F-B87D-0C8162E0F0C8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{17689B4B-7361-417F-B87D-0C8162E0F0C8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{17689B4B-7361-417F-B87D-0C8162E0F0C8}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -76,5 +82,9 @@ Global
 		{13BE838A-200B-4A68-8F58-3EA3BE3A1A8A} = {F9BA869A-7D5F-420F-9505-2D881F7934A7}
 		{2AE82E1C-6CE1-4755-A332-FA359B7CCE72} = {F9BA869A-7D5F-420F-9505-2D881F7934A7}
 		{33FB5967-62C7-4230-B515-780EF63F748E} = {E05DCF88-F916-4B61-A5DC-A8344C9E2429}
+		{17689B4B-7361-417F-B87D-0C8162E0F0C8} = {F9BA869A-7D5F-420F-9505-2D881F7934A7}
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {386F8E33-9F3E-4BC3-B895-A0B43372552F}
 	EndGlobalSection
 EndGlobal

src/Microsoft.Extensions.HealthChecks.MongoDb/HealthCheckBuilderMongoDbExtensions.cs

@@ -0,0 +1,49 @@
+using System;
+using MongoDB.Bson;
+using MongoDB.Driver;
+
+namespace Microsoft.Extensions.HealthChecks
+{
+    using System.Linq;
+    using MongoDB.Driver.Core.Servers;
+
+    public static class HealthCheckBuilderMongoDbExtensions
+    {
+        public static HealthCheckBuilder AddMongoDbCheck(this HealthCheckBuilder builder, string name, string connectionString, string databaseName)
+        {
+            Guard.ArgumentNotNull(nameof(builder), builder);
+
+            return AddMongoDbCheck(builder, name, connectionString, databaseName, builder.DefaultCacheDuration);
+        }
+
+        public static HealthCheckBuilder AddMongoDbCheck(this HealthCheckBuilder builder, string name, string connectionString, string databaseName, TimeSpan cacheDuration)
+        {
+            builder.AddCheck($"MongoDbCheck({name})", async () =>
+            {
+                try
+                {
+                    var client = new MongoClient(connectionString);
+                    IMongoDatabase database = client.GetDatabase(databaseName);
+
+                    ServerState serverState = client.Cluster.Description.Servers.FirstOrDefault()?.State
+                                              ?? ServerState.Disconnected;
+
+                    if (serverState == ServerState.Disconnected)
+                    {
+                        return HealthCheckResult.Unhealthy($"MongoDbCheck({name}): Unhealthy");
+                    }
+
+                    BsonDocument result = await database.RunCommandAsync((Command<BsonDocument>) "{ping:1}").ConfigureAwait(false);
+
+                    return HealthCheckResult.Healthy($"MongoDbCheck({name}): Healthy");
+                }
+                catch (Exception ex)
+                {
+                    return HealthCheckResult.Unhealthy($"MongoDbCheck({name}): Exception during check: {ex.GetType().FullName}");
+                }
+            }, cacheDuration);
+
+            return builder;
+        }
+    }
+}

src/Microsoft.Extensions.HealthChecks.MongoDb/Microsoft.Extensions.HealthChecks.MongoDb.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard1.5</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="MongoDB.Driver" Version="2.4.4" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Microsoft.Extensions.HealthChecks\Microsoft.Extensions.HealthChecks.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="..\common\Guard.cs" Link="Internal\Guard.cs" />
+  </ItemGroup>
+
+</Project>