Internal resource state monitoring

Author: Danila Polevshchikov

Greentube.Monitoring.sln

@@ -40,6 +40,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Greentube.Monitoring.Apache
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Greentube.Monitoring.IntegrationTests", "test\Greentube.Monitoring.IntegrationTests\Greentube.Monitoring.IntegrationTests.csproj", "{B9FAE3D9-FB45-479B-ADAE-5A81B0EED0A8}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Greentube.Monitoring.InternalResource", "src\Greentube.Monitoring.InternalResource\Greentube.Monitoring.InternalResource.csproj", "{6C953298-9D57-49A7-8123-C110A99EADA6}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Coverage|Any CPU = Coverage|Any CPU
@@ -125,6 +127,12 @@ Global
 		{B9FAE3D9-FB45-479B-ADAE-5A81B0EED0A8}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{B9FAE3D9-FB45-479B-ADAE-5A81B0EED0A8}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{B9FAE3D9-FB45-479B-ADAE-5A81B0EED0A8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6C953298-9D57-49A7-8123-C110A99EADA6}.Coverage|Any CPU.ActiveCfg = Debug|Any CPU
+		{6C953298-9D57-49A7-8123-C110A99EADA6}.Coverage|Any CPU.Build.0 = Debug|Any CPU
+		{6C953298-9D57-49A7-8123-C110A99EADA6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6C953298-9D57-49A7-8123-C110A99EADA6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6C953298-9D57-49A7-8123-C110A99EADA6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6C953298-9D57-49A7-8123-C110A99EADA6}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -143,6 +151,7 @@ Global
 		{D5DEE9C7-0A0A-4789-BD75-F78F5037C69A} = {843C8ED0-4792-40E0-8903-A3E5FF74A0A3}
 		{DA5A72B9-EEED-4CFF-97A4-C5FE6BC90FB6} = {AE749C50-94C1-445C-B13F-E9D19372CBDB}
 		{B9FAE3D9-FB45-479B-ADAE-5A81B0EED0A8} = {AE749C50-94C1-445C-B13F-E9D19372CBDB}
+		{6C953298-9D57-49A7-8123-C110A99EADA6} = {843C8ED0-4792-40E0-8903-A3E5FF74A0A3}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {BC80F7F7-4B53-4822-BFCB-50AC6E0EE384}

src/Greentube.Monitoring.InternalResource/Greentube.Monitoring.InternalResource.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="1.0.2" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Greentube.Monitoring\Greentube.Monitoring.csproj" />
+  </ItemGroup>
+
+</Project>

src/Greentube.Monitoring.InternalResource/IInternalResourceMonitored.cs

@@ -0,0 +1,16 @@
+namespace Greentube.Monitoring.InternalResource
+{
+    /// <summary>
+    /// Represents internal resource state
+    /// </summary>
+    public interface IInternalResourceMonitored
+    {
+    /// <summary>
+    /// Gets a value indicating whether this resource is up.
+    /// </summary>
+    /// <value>
+    ///   <c>true</c> if this instance is up; otherwise, <c>false</c>.
+    /// </value>
+    bool IsUp { get; }
+    }
+}

src/Greentube.Monitoring.InternalResource/InternalResourceHealthCheckStrategy.cs

@@ -0,0 +1,20 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Greentube.Monitoring.InternalResource
+{
+    public sealed class InternalResourceHealthCheckStrategy : IHealthCheckStrategy
+    {
+        private readonly IInternalResourceMonitored _internalResourceMonitored;
+
+        public InternalResourceHealthCheckStrategy(IInternalResourceMonitored internalResourceMonitored)
+        {
+            _internalResourceMonitored = internalResourceMonitored;
+        }
+
+        public Task<bool> Check(CancellationToken token)
+        {
+            return Task.FromResult(_internalResourceMonitored.IsUp);
+        }
+    }
+}

src/Greentube.Monitoring.InternalResource/InternalResourceMonitor.cs

@@ -0,0 +1,21 @@
+using Microsoft.Extensions.Logging;
+
+namespace Greentube.Monitoring.InternalResource
+{
+    /// <summary>
+    /// Internal resource monitor
+    ///<seealso cref="ResourceMonitor" />
+    /// </summary>
+    public sealed class InternalResourceMonitor : ResourceMonitor
+    {
+        public InternalResourceMonitor(
+            string resourceName,
+            InternalResourceHealthCheckStrategy verificationStrategy,
+            IResourceMonitorConfiguration configuration,
+            ILogger<ResourceMonitor> logger,
+            bool isCritical = false)
+            : base(resourceName, verificationStrategy, configuration, logger, isCritical)
+        {
+        }
+    }
+}

src/Greentube.Monitoring.InternalResource/InternalResourceMonitorExtensions.cs

@@ -0,0 +1,35 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace Greentube.Monitoring.InternalResource
+{
+    public static class InternalResourceMonitoringExtensions
+    {
+        /// <summary>
+        /// Adds the internal resource monitor.
+        /// </summary>
+        /// <param name="options">The options.</param>
+        /// <param name="internalResource">Instance of internal resource that has state</param>
+        /// <param name="resourceName">Name of the resource. Defaults to: Uri.AbsoluteUri.</param>
+        /// <param name="isCritical">if set to <c>true</c> [is critical].</param>
+        /// <param name="configOverride">The configuration override.</param>
+        public static void AddInternalResourceMonitor(
+            this MonitoringOptions options,
+            IInternalResourceMonitored internalResource,
+            string resourceName,
+            bool isCritical = false,
+            IResourceMonitorConfiguration configOverride = null)
+        {
+            options.AddResourceMonitor((conf, provider) =>
+            {
+                var logger = provider.GetRequiredService<ILogger<InternalResourceMonitor>>();
+                return new InternalResourceMonitor(
+                    resourceName,
+                    new InternalResourceHealthCheckStrategy(internalResource), 
+                    configOverride ?? conf,
+                    logger, isCritical
+                );
+            });
+        }
+    }
+}

test/Greentube.Monitoring.IntegrationTests/Greentube.Monitoring.IntegrationTests.csproj

@@ -19,6 +19,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\..\src\Greentube.Monitoring.AkkaCluster\Greentube.Monitoring.InternalResource.csproj" />
     <ProjectReference Include="..\..\src\Greentube.Monitoring.AspNetCore\Greentube.Monitoring.AspNetCore.csproj" />
     <ProjectReference Include="..\..\src\Greentube.Monitoring\Greentube.Monitoring.csproj" />
   </ItemGroup>

test/Greentube.Monitoring.IntegrationTests/InternalResourceMonitorTests.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.TestHost;
+using Microsoft.Extensions.DependencyInjection;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace Greentube.Monitoring.IntegrationTests
+{
+    public class InternalResourceMonitorTests
+    {
+        private readonly TestServer _server;
+
+        public InternalResourceMonitorTests()
+        {
+            var webHostBuilder = new WebHostBuilder();
+            _server = new TestServer(webHostBuilder.UseStartup<TestStartup>());
+        }
+
+        [Fact]
+        public async Task InternalStateIsMonitored()
+        {
+            var client = _server.CreateClient();
+
+            // check if node is up
+            var healthCheckResponse = await GetHealth(client);
+            Assert.True(healthCheckResponse.Up);
+            
+            // set internalState to down
+            await client.GetAsync("/?SetToDown");
+
+            await Task.Delay(TimeSpan.FromMilliseconds(500));
+            // check if node is down
+            healthCheckResponse = await GetHealth(client);
+            Assert.False(healthCheckResponse.Up);
+        }
+
+        private static async Task<HealthCheckResponse> GetHealth(HttpClient client)
+        {
+            var httpResponseMessage = await client.GetAsync("/health?Detailed");
+            var content = await httpResponseMessage.Content.ReadAsStringAsync();
+            var healthCheckResponse =
+                JsonConvert.DeserializeObject<HealthCheckResponse>(content);
+            return healthCheckResponse;
+        }
+
+        private class HealthCheckResponse
+        {
+            public bool Up { get; set; }
+        }
+    }
+}

test/Greentube.Monitoring.IntegrationTests/SimpleInternalResource.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Greentube.Monitoring.InternalResource;
+
+namespace Greentube.Monitoring.IntegrationTests
+{
+    class SimpleInternalResource: IInternalResourceMonitored
+    {
+        public bool IsUp { get; set;  } = false;
+    }
+}

test/Greentube.Monitoring.IntegrationTests/TestStartup.cs

@@ -1,26 +1,40 @@
 using System;
 using System.Reflection;
 using Greentube.Monitoring.DependencyInjection;
+using Greentube.Monitoring.InternalResource;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 
+
 namespace Greentube.Monitoring.IntegrationTests
 {
     public sealed class TestStartup
     {
+        private SimpleInternalResource _testInternalResource;
         public IServiceProvider ConfigureServices(IServiceCollection services)
         {
+            _testInternalResource = new SimpleInternalResource { IsUp = true };
             services.AddMonitoring(Assembly.GetEntryAssembly(), options =>
             {
                 options.AddShutdownMonitor(configOverride:new ResourceMonitorConfiguration(true, TimeSpan.FromMilliseconds(100), TimeSpan.FromMilliseconds(100)));
+                options.AddInternalResourceMonitor(_testInternalResource, "simple resource", configOverride: new ResourceMonitorConfiguration(true, TimeSpan.FromMilliseconds(100), TimeSpan.FromMilliseconds(100)), isCritical: true);
             });
             return services.BuildServiceProvider();
         }
 
         public void Configure(IApplicationBuilder app, IHostingEnvironment env)
         {
             app.UseMonitoringEndpoint(options => options.Path = "/health");
+
+            app.Run(async context =>
+            {
+                if (context.Request.Query.ContainsKey("SetToUp"))
+                    { _testInternalResource.IsUp = true;}
+
+                if (context.Request.Query.ContainsKey("SetToDown"))
+                    { _testInternalResource.IsUp = false; }
+            });
         }
     }
 }