Updates health check json response with additional descriptions and "…

…data" to describe what makes the system degraded or unhealthy.
Kritner-Blogs · Dec 4, 2020 · 952166e · 952166e
1 parent eb49863
commit 952166e
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Showing 6 changed files with 77 additions and 59 deletions.
diff --git a/src/Kritner.Orleans.GettingStarted.Grains/HealthChecks/BasicHealthCheckGrain.cs b/src/Kritner.Orleans.GettingStarted.Grains/HealthChecks/BasicHealthCheckGrain.cs
@@ -10,9 +10,11 @@ namespace Kritner.Orleans.GettingStarted.Grains.HealthChecks
 	[StatelessWorker(1)]
 	public class BasicHealthCheckGrain : Grain, IBasicHealthCheckGrain
 	{
+		private const string HealthCheckDescription = "A basic health check.  Should only ever return healthy assuming the Orleans cluster is up.";
+
 		public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = new CancellationToken())
 		{
-			return Task.FromResult(new HealthCheckResult(HealthStatus.Healthy));
+			return Task.FromResult(new HealthCheckResult(HealthStatus.Healthy, HealthCheckDescription));
 		}
 	}
 }
diff --git a/src/Kritner.Orleans.GettingStarted.Grains/HealthChecks/CpuHealthCheckGrain.cs b/src/Kritner.Orleans.GettingStarted.Grains/HealthChecks/CpuHealthCheckGrain.cs
@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Threading;
 using System.Threading.Tasks;
 using Kritner.Orleans.GettingStarted.GrainInterfaces.HealthChecks;
@@ -13,6 +15,12 @@ public class CpuHealthCheckGrain : Grain, ICpuHealthCheckGrain
 	{
 		private const float UnhealthyThreshold = 90;
 		private const float DegradedThreshold = 70;
+		private readonly ReadOnlyDictionary<string, object> HealthCheckData = new ReadOnlyDictionary<string, object>(
+			new Dictionary<string, object>()
+			{
+				{ "Unhealthy Threshold",  UnhealthyThreshold},
+				{ "Degraded Threshold",  DegradedThreshold}
+			});
 
 		private readonly IHostEnvironmentStatistics _hostEnvironmentStatistics;
 
@@ -25,23 +33,23 @@ public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, Canc
 		{
 			if (_hostEnvironmentStatistics.CpuUsage == null)
 			{
-				return Task.FromResult(HealthCheckResult.Unhealthy("Could not determine CPU usage."));
+				return Task.FromResult(HealthCheckResult.Unhealthy("Could not determine CPU usage.", data: HealthCheckData));
 			}
 
 			if (_hostEnvironmentStatistics.CpuUsage > UnhealthyThreshold)
 			{
 				return Task.FromResult(HealthCheckResult.Unhealthy(
-					$"CPU utilization is unhealthy at {_hostEnvironmentStatistics.CpuUsage}%."));
+					$"CPU utilization is unhealthy at {_hostEnvironmentStatistics.CpuUsage:0.00}%.", data: HealthCheckData));
 			}
 
 			if (_hostEnvironmentStatistics.CpuUsage > DegradedThreshold)
 			{
 				return Task.FromResult(HealthCheckResult.Degraded(
-					$"CPU utilization is degraded at {_hostEnvironmentStatistics.CpuUsage}%."));
+					$"CPU utilization is degraded at {_hostEnvironmentStatistics.CpuUsage:0.00}%.", data: HealthCheckData));
 			}
 
 			return Task.FromResult(HealthCheckResult.Healthy(
-				$"CPU utilization is healthy at {_hostEnvironmentStatistics.CpuUsage}%."));
+				$"CPU utilization is healthy at {_hostEnvironmentStatistics.CpuUsage:0.00}%.", data: HealthCheckData));
 		}
 	}
 }
diff --git a/src/Kritner.Orleans.GettingStarted.Grains/HealthChecks/MemoryHealthCheckGrain.cs b/src/Kritner.Orleans.GettingStarted.Grains/HealthChecks/MemoryHealthCheckGrain.cs
@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Threading;
 using System.Threading.Tasks;
 using Kritner.Orleans.GettingStarted.GrainInterfaces.HealthChecks;
@@ -12,8 +14,15 @@ namespace Kritner.Orleans.GettingStarted.Grains.HealthChecks
 	public class MemoryHealthCheckGrain : Grain, IMemoryHealthCheckGrain
 	{
 		private const float UnhealthyThreshold = 95;
-		private const float DegradedThreshold = 90;
-
+		private const float DegradedThreshold = 90;
+
+		private readonly ReadOnlyDictionary<string, object> HealthCheckData = new ReadOnlyDictionary<string, object>(
+			new Dictionary<string, object>()
+			{
+						{ "Unhealthy Threshold",  UnhealthyThreshold},
+						{ "Degraded Threshold",  DegradedThreshold}
+			});
+
 		private readonly IHostEnvironmentStatistics _hostEnvironmentStatistics;
 
 		public MemoryHealthCheckGrain(IHostEnvironmentStatistics hostEnvironmentStatistics)
@@ -25,31 +34,31 @@ public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, Canc
 		{
 			if (_hostEnvironmentStatistics?.AvailableMemory == null || _hostEnvironmentStatistics?.TotalPhysicalMemory == null)
 			{
-				return Task.FromResult(HealthCheckResult.Unhealthy("Could not determine memory calculation."));
+				return Task.FromResult(HealthCheckResult.Unhealthy("Could not determine memory calculation.", data: HealthCheckData));
 			}
 
 			if (_hostEnvironmentStatistics?.AvailableMemory == 0 && _hostEnvironmentStatistics?.AvailableMemory == 0)
 			{
-				return Task.FromResult(HealthCheckResult.Unhealthy("Could not determine memory calculation."));
+				return Task.FromResult(HealthCheckResult.Unhealthy("Could not determine memory calculation.", data: HealthCheckData));
 			}
 
 			var memoryUsed = 100 - ((float)_hostEnvironmentStatistics.AvailableMemory / (float)_hostEnvironmentStatistics.TotalPhysicalMemory * 100);
 
 			if (memoryUsed > UnhealthyThreshold)
 			{
 				return Task.FromResult(HealthCheckResult.Unhealthy(
-					$"Memory utilization is unhealthy at {memoryUsed:0.00}%."));
+					$"Memory utilization is unhealthy at {memoryUsed:0.00}%.", data: HealthCheckData));
 
 			}
 
 			if (memoryUsed > DegradedThreshold)
 			{
 				return Task.FromResult(HealthCheckResult.Degraded(
-					$"Memory utilization is degraded at {memoryUsed:0.00}%."));
+					$"Memory utilization is degraded at {memoryUsed:0.00}%.", data: HealthCheckData));
 			}
 
 			return Task.FromResult(HealthCheckResult.Healthy(
-				$"Memory utilization is healthy at {memoryUsed:0.00}%."));
+				$"Memory utilization is healthy at {memoryUsed:0.00}%.", data: HealthCheckData));
 		}
 	}
 }
diff --git a/src/Kritner.OrleansGettingStarted.SiloHost/Helpers/HealthCheckResponseWriter.cs b/src/Kritner.OrleansGettingStarted.SiloHost/Helpers/HealthCheckResponseWriter.cs
@@ -0,0 +1,35 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Threading.Tasks;
+
+namespace Kritner.OrleansGettingStarted.SiloHost.Helpers
+{
+    internal static class HealthCheckResponseWriter
+    {
+		public static Task WriteResponse(HttpContext context, HealthReport healthReport)
+		{
+			context.Response.ContentType = "application/json; charset=utf-8";
+
+			var result = JsonConvert.SerializeObject(new
+			{
+				status = healthReport.Status.ToString(),
+				details = healthReport.Entries.Select(e => new
+				{
+					key = e.Key,
+					description = e.Value.Description,
+					status = e.Value.Status.ToString(),
+					data = e.Value.Data
+				})
+			}, Formatting.Indented);
+
+			return context.Response.WriteAsync(result);
+		}
+	}
+}
diff --git a/src/Kritner.OrleansGettingStarted.SiloHost/Program.cs b/src/Kritner.OrleansGettingStarted.SiloHost/Program.cs
@@ -34,7 +34,14 @@ private static IHostBuilder CreateHostBuilder(string[] args, string env, IConfig
                     builder.AddConfiguration(configurationRoot);
                 })
                 .ConfigureServices(DependencyInjectionHelper.IocContainerRegistration)
-                .ConfigureWebHostDefaults(builder => { builder.UseStartup<Startup>(); })
+                .ConfigureLogging(logging => {
+                    logging.AddConsole();
+                    logging.SetMinimumLevel(LogLevel.Information);
+                })
+                .ConfigureWebHostDefaults(builder => 
+                { 
+                    builder.UseStartup<Startup>();
+                })
                 .UseOrleans(siloBuilder =>
                 {
                     siloBuilder

diff --git a/src/Kritner.OrleansGettingStarted.SiloHost/Startup.cs b/src/Kritner.OrleansGettingStarted.SiloHost/Startup.cs
@@ -1,16 +1,11 @@
-using System.IO;
-using System.Text;
-using System.Text.Json;
-using System.Threading.Tasks;
 using Kritner.OrleansGettingStarted.SiloHost.HealthChecks;
+using Kritner.OrleansGettingStarted.SiloHost.Helpers;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Diagnostics.HealthChecks;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Diagnostics.HealthChecks;
 using Microsoft.Extensions.Hosting;
 
 namespace Kritner.OrleansGettingStarted.SiloHost
@@ -43,6 +38,7 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 			}
 
 			app.UseHttpsRedirection();
+			app.UseHsts();
 
 			app.UseRouting();
 
@@ -55,51 +51,12 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 						new HealthCheckOptions
 						{
 							AllowCachingResponses = false,
-							ResponseWriter = WriteResponse
+							ResponseWriter = HealthCheckResponseWriter.WriteResponse
 						})
 					.WithMetadata(new AllowAnonymousAttribute());
 				endpoints.MapControllers();
 			});
 		}
 
-		private static Task WriteResponse(HttpContext context, HealthReport result)
-		{
-			context.Response.ContentType = "application/json; charset=utf-8";
-
-			var options = new JsonWriterOptions
-			{
-				Indented = true
-			};
-
-			using var stream = new MemoryStream();
-			using (var writer = new Utf8JsonWriter(stream, options))
-			{
-				writer.WriteStartObject();
-				writer.WriteString("status", result.Status.ToString());
-				writer.WriteStartObject("results");
-				foreach (var entry in result.Entries)
-				{
-					writer.WriteStartObject(entry.Key);
-					writer.WriteString("status", entry.Value.Status.ToString());
-					writer.WriteString("description", entry.Value.Description);
-					writer.WriteStartObject("data");
-					foreach (var item in entry.Value.Data)
-					{
-						writer.WritePropertyName(item.Key);
-						JsonSerializer.Serialize(
-							writer, item.Value, item.Value?.GetType() ??
-							                    typeof(object));
-					}
-					writer.WriteEndObject();
-					writer.WriteEndObject();
-				}
-				writer.WriteEndObject();
-				writer.WriteEndObject();
-			}
-
-			var json = Encoding.UTF8.GetString(stream.ToArray());
-
-			return context.Response.WriteAsync(json);
-		}
 	}
 }