Add MySql health check

HealthChecks.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26228.9
+VisualStudioVersion = 15.0.26730.12
 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("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.Extensions.HealthChecks.MySql", "src\Microsoft.Extensions.HealthChecks.MySql\Microsoft.Extensions.HealthChecks.MySql.csproj", "{29044153-D1A0-4B7E-9B1E-7587737506A0}"
+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
+		{29044153-D1A0-4B7E-9B1E-7587737506A0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{29044153-D1A0-4B7E-9B1E-7587737506A0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{29044153-D1A0-4B7E-9B1E-7587737506A0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{29044153-D1A0-4B7E-9B1E-7587737506A0}.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}
+		{29044153-D1A0-4B7E-9B1E-7587737506A0} = {F9BA869A-7D5F-420F-9505-2D881F7934A7}
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {C19929B3-8E3C-4D58-9873-1EE86EF82CE1}
 	EndGlobalSection
 EndGlobal

samples/SampleHealthChecker.AspNetCore/SampleHealthChecker.AspNetCore.csproj

@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Microsoft.AspNetCore.HealthChecks\Microsoft.AspNetCore.HealthChecks.csproj" />
+    <ProjectReference Include="..\..\src\Microsoft.Extensions.HealthChecks.MySql\Microsoft.Extensions.HealthChecks.MySql.csproj" />
     <ProjectReference Include="..\..\src\Microsoft.Extensions.HealthChecks\Microsoft.Extensions.HealthChecks.csproj" />
   </ItemGroup>
 

samples/SampleHealthChecker.AspNetCore/Startup.cs

@@ -49,7 +49,8 @@ public void ConfigureServices(IServiceCollection services)
                       )
                       .AddCheck("thrower", (Func<IHealthCheckResult>)(() => { throw new DivideByZeroException(); }))
                       .AddCheck("long-running", async cancellationToken => { await Task.Delay(10000, cancellationToken); return HealthCheckResult.Healthy("I ran too long"); })
-                      .AddCheck<CustomHealthCheck>("custom");
+                      .AddCheck<CustomHealthCheck>("custom")
+                      .AddMySqlCheck("mysql", "MySql Connection String", TimeSpan.Zero);
 
                 /*
                 // add valid storage account credentials first

src/Microsoft.Extensions.HealthChecks.MySql/HealthCheckBuilderMySqlServerExtensions.cs

@@ -0,0 +1,44 @@
+using MySql.Data.MySqlClient;
+using System;
+
+namespace Microsoft.Extensions.HealthChecks
+{
+    public static class HealthCheckBuilderMySqlServerExtensions
+    {
+        public static HealthCheckBuilder AddMySqlCheck(this HealthCheckBuilder builder, string name, string connectionString)
+        {
+            Guard.ArgumentNotNull(nameof(builder), builder);
+
+            return AddMySqlCheck(builder, name, connectionString, builder.DefaultCacheDuration);
+        }
+
+        public static HealthCheckBuilder AddMySqlCheck(this HealthCheckBuilder builder, string name, string connectionString, TimeSpan cacheDuration)
+        {
+            builder.AddCheck($"MySqlCheck({name})", async () =>
+            {
+                try
+                {
+                    using (var connection = new MySqlConnection(connectionString))
+                    {
+                        connection.Open();
+                        using (var cmd = new MySqlCommand("SHOW STATUS", connection))
+                        {
+                            var result = await cmd.ExecuteReaderAsync();
+                            if(result.HasRows)
+                            {
+                                return HealthCheckResult.Healthy($"MySqlCheck({name}): Healthy");
+                            }
+                            return HealthCheckResult.Unhealthy($"MySqlCheck({name}): Unhealthy");
+                        }
+                    }
+                }
+                catch (Exception ex)
+                {
+                    return HealthCheckResult.Unhealthy($"MySqlCheck({name}): Exception during check: {ex.GetType().FullName}");
+                }
+            }, cacheDuration);
+
+            return builder;
+        }
+    }
+}

src/Microsoft.Extensions.HealthChecks.MySql/Microsoft.Extensions.HealthChecks.MySql.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>netstandard1.3</TargetFramework>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <Compile Include="..\common\Guard.cs" Link="Internal\Guard.cs" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <PackageReference Include="MySqlConnector" Version="0.28.0" />
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\Microsoft.Extensions.HealthChecks\Microsoft.Extensions.HealthChecks.csproj" />
+    </ItemGroup>
+
+</Project>