Added Tags to health checks

Src/Metrics/Core/HealthCheck.cs

@@ -8,35 +8,39 @@ public struct Result
         {
             public readonly string Name;
             public readonly HealthCheckResult Check;
+            public readonly MetricTags Tags;
 
-            public Result(string name, HealthCheckResult check)
+            public Result(string name, HealthCheckResult check, MetricTags tags = default(MetricTags))
             {
                 this.Name = name;
                 this.Check = check;
+                this.Tags = tags;
             }
         }
 
         private readonly Func<HealthCheckResult> check;
 
-        protected HealthCheck(string name)
-            : this(name, () => { })
+        protected HealthCheck(string name, MetricTags tags = default(MetricTags))
+            : this(name, () => { }, tags)
         { }
 
-        public HealthCheck(string name, Action check)
-            : this(name, () => { check(); return string.Empty; })
+        public HealthCheck(string name, Action check, MetricTags tags = default(MetricTags))
+            : this(name, () => { check(); return string.Empty; }, tags)
         { }
 
-        public HealthCheck(string name, Func<string> check)
-            : this(name, () => HealthCheckResult.Healthy(check()))
+        public HealthCheck(string name, Func<string> check, MetricTags tags = default(MetricTags))
+            : this(name, () => HealthCheckResult.Healthy(check()), tags)
         { }
 
-        public HealthCheck(string name, Func<HealthCheckResult> check)
+        public HealthCheck(string name, Func<HealthCheckResult> check, MetricTags tags = default(MetricTags))
         {
             this.Name = name;
             this.check = check;
+            this.Tags = tags;
         }
 
         public string Name { get; }
+        public MetricTags Tags { get; set; }
 
         protected virtual HealthCheckResult Check()
         {
@@ -47,11 +51,11 @@ public Result Execute()
         {
             try
             {
-                return new Result(this.Name, this.Check());
+                return new Result(this.Name, this.Check(), Tags);
             }
             catch (Exception x)
             {
-                return new Result(this.Name, HealthCheckResult.Unhealthy(x));
+                return new Result(this.Name, HealthCheckResult.Unhealthy(x), Tags);
             }
         }
     }

Src/Metrics/HealthChecks.cs

@@ -46,9 +46,10 @@ public static class HealthChecks
         /// </summary>
         /// <param name="name">Name of the health check.</param>
         /// <param name="check">Action to execute.</param>
-        public static void RegisterHealthCheck(string name, Action check)
+        /// <param name="tags">Optional set of tags that can be associated with the health check.</param>
+        public static void RegisterHealthCheck(string name, Action check, MetricTags tags = default(MetricTags))
         {
-            RegisterHealthCheck(new HealthCheck(name, check));
+            RegisterHealthCheck(new HealthCheck(name, check, tags));
         }
 
         /// <summary>
@@ -57,9 +58,10 @@ public static void RegisterHealthCheck(string name, Action check)
         /// </summary>
         /// <param name="name">Name of the health check.</param>
         /// <param name="check">Function to execute.</param>
-        public static void RegisterHealthCheck(string name, Func<string> check)
+        /// <param name="tags">Optional set of tags that can be associated with the health check.</param>
+        public static void RegisterHealthCheck(string name, Func<string> check, MetricTags tags = default(MetricTags))
         {
-            RegisterHealthCheck(new HealthCheck(name, check));
+            RegisterHealthCheck(new HealthCheck(name, check, tags));
         }
 
         /// <summary>
@@ -68,9 +70,10 @@ public static void RegisterHealthCheck(string name, Func<string> check)
         /// </summary>
         /// <param name="name">Name of the health check.</param>
         /// <param name="check">Function to execute</param>
-        public static void RegisterHealthCheck(string name, Func<HealthCheckResult> check)
+        /// <param name="tags">Optional set of tags that can be associated with the health check.</param>
+        public static void RegisterHealthCheck(string name, Func<HealthCheckResult> check, MetricTags tags = default(MetricTags))
         {
-            RegisterHealthCheck(new HealthCheck(name, check));
+            RegisterHealthCheck(new HealthCheck(name, check, tags));
         }
 
         /// <summary>

Src/Metrics/Json/JsonHealthChecks.cs → Src/Metrics/Json/JsonHealthChecksV1.cs

@@ -5,7 +5,7 @@
 
 namespace Metrics.Json
 {
-    public class JsonHealthChecks
+    public class JsonHealthChecksV1
     {
         public const int Version = 1;
         public const string HealthChecksMimeType = "application/vnd.metrics.net.v1.health+json";
@@ -15,26 +15,26 @@ public class JsonHealthChecks
         public static string BuildJson(HealthStatus status) { return BuildJson(status, Clock.Default, indented: false); }
         public static string BuildJson(HealthStatus status, Clock clock, bool indented = true)
         {
-            return new JsonHealthChecks()
+            return new JsonHealthChecksV1()
                .AddVersion(Version)
                .AddTimestamp(Clock.Default)
                .AddObject(status)
                .GetJson(indented);
         }
 
-        public JsonHealthChecks AddVersion(int version)
+        public JsonHealthChecksV1 AddVersion(int version)
         {
             root.Add(new JsonProperty("Version", version.ToString(CultureInfo.InvariantCulture)));
             return this;
         }
 
-        public JsonHealthChecks AddTimestamp(Clock clock)
+        public JsonHealthChecksV1 AddTimestamp(Clock clock)
         {
             root.Add(new JsonProperty("Timestamp", Clock.FormatTimestamp(clock.UTCDateTime)));
             return this;
         }
 
-        public JsonHealthChecks AddObject(HealthStatus status)
+        public JsonHealthChecksV1 AddObject(HealthStatus status)
         {
             var properties = new List<JsonProperty>() { new JsonProperty("IsHealthy", status.IsHealthy) };
             var unhealty = status.Results.Where(r => !r.Check.IsHealthy)

Src/Metrics/Json/JsonHealthChecksV2.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using Metrics.Core;
+using Metrics.Utils;
+
+namespace Metrics.Json
+{
+    public class JsonHealthChecksV2
+    {
+        public const int Version = 2;
+        public const string HealthChecksMimeType = "application/vnd.metrics.net.v2.health+json";
+
+        private readonly List<JsonProperty> root = new List<JsonProperty>();
+
+        public static string BuildJson(HealthStatus status) { return BuildJson(status, Clock.Default, indented: false); }
+        public static string BuildJson(HealthStatus status, Clock clock, bool indented = true)
+        {
+            return new JsonHealthChecksV2()
+               .AddVersion(Version)
+               .AddTimestamp(Clock.Default)
+               .AddObject(status)
+               .GetJson(indented);
+        }
+
+        public JsonHealthChecksV2 AddVersion(int version)
+        {
+            root.Add(new JsonProperty("Version", version.ToString(CultureInfo.InvariantCulture)));
+            return this;
+        }
+
+        public JsonHealthChecksV2 AddTimestamp(Clock clock)
+        {
+            root.Add(new JsonProperty("Timestamp", Clock.FormatTimestamp(clock.UTCDateTime)));
+            return this;
+        }
+
+        public JsonHealthChecksV2 AddObject(HealthStatus status)
+        {
+            var properties = new List<JsonProperty>() { new JsonProperty("IsHealthy", status.IsHealthy) };
+            var unhealty = status.Results.Where(r => !r.Check.IsHealthy);
+            properties.Add(new JsonProperty("Unhealthy", CreateHealthJsonObject(unhealty)));
+            var healthy = status.Results.Where(r => r.Check.IsHealthy);
+            properties.Add(new JsonProperty("Healthy", CreateHealthJsonObject(healthy)));
+            this.root.AddRange(properties);
+            return this;
+        }
+
+        private IEnumerable<JsonObject> CreateHealthJsonObject(IEnumerable<HealthCheck.Result> results)
+        {
+            return results.Select(r => new JsonObject(new List<JsonProperty>()
+            {
+                new JsonProperty("Name", r.Name),
+                new JsonProperty("Message", r.Check.Message),
+                new JsonProperty("Tags", r.Tags.Tags)
+            }));
+        }
+
+        public string GetJson(bool indented = true)
+        {
+            return new JsonObject(root).AsJson(indented);
+        }
+    }
+}

Src/Metrics/Metrics.csproj

@@ -88,6 +88,7 @@
     <Compile Include="Core\DefaultDataProvider.cs" />
     <Compile Include="Core\DefaultRegistryDataProvider.cs" />
     <Compile Include="Core\SimpleMeter.cs" />
+    <Compile Include="Json\JsonHealthChecksV2.cs" />
     <Compile Include="Json\JsonMetric.cs" />
     <Compile Include="Json\JsonMetricsContext.cs" />
     <Compile Include="Json\JsonTimer.cs" />
@@ -96,7 +97,7 @@
     <Compile Include="Json\JsonGauge.cs" />
     <Compile Include="Json\JsonCounter.cs" />
     <Compile Include="Core\ReadOnlyMetricsContext.cs" />
-    <Compile Include="Json\JsonHealthChecks.cs" />
+    <Compile Include="Json\JsonHealthChecksV1.cs" />
     <Compile Include="MetricData\ConstantValue.cs" />
     <Compile Include="MetricData\CounterValue.cs" />
     <Compile Include="MetricData\EnvironmentEntry.cs" />

Src/Metrics/Reporters/EndpointReporterConfig.cs

@@ -15,22 +15,62 @@ public static MetricsEndpointReports WithTextReport(this MetricsEndpointReports
             return reports.WithEndpointReport(endpoint, (d, h, c) => new MetricsEndpointResponse(StringReport.RenderMetrics(d, h), "text/plain"));
         }
 
+        #region HealthChecks
+
+        public static MetricsEndpointReports WithJsonHealthV1Report(this MetricsEndpointReports reports, string endpoint, bool alwaysReturnOkStatusCode = false)
+        {
+            return reports.WithEndpointReport(endpoint, (d, h, r) => GetHealthResponse(h, JsonHealthChecksV1.BuildJson, JsonHealthChecksV1.HealthChecksMimeType, alwaysReturnOkStatusCode));
+        }
+
+        public static MetricsEndpointReports WithJsonHealthV2Report(this MetricsEndpointReports reports, string endpoint, bool alwaysReturnOkStatusCode = false)
+        {
+            return reports.WithEndpointReport(endpoint, (d, h, r) => GetHealthResponse(h, JsonHealthChecksV2.BuildJson, JsonHealthChecksV2.HealthChecksMimeType, alwaysReturnOkStatusCode));
+        }
+
         public static MetricsEndpointReports WithJsonHealthReport(this MetricsEndpointReports reports, string endpoint, bool alwaysReturnOkStatusCode = false)
         {
-            return reports.WithEndpointReport(endpoint, (d, h, r) => GetHealthResponse(h, alwaysReturnOkStatusCode));
+            return reports.WithEndpointReport(endpoint, (d, h, r) => GetHealthResponse(h, GetJsonHealthCreator(r), GetJsonHealthMimeType(r), alwaysReturnOkStatusCode));
         }
 
-        private static MetricsEndpointResponse GetHealthResponse(Func<HealthStatus> healthStatus, bool alwaysReturnOkStatusCode)
+        private static MetricsEndpointResponse GetHealthResponse(Func<HealthStatus> healthStatus, Func<HealthStatus, string> jsonCreator, string healthMimeType, bool alwaysReturnOkStatusCode)
         {
             var status = healthStatus();
-            var json = JsonHealthChecks.BuildJson(status);
+            var json = jsonCreator(status);
 
             var httpStatus = status.IsHealthy || alwaysReturnOkStatusCode ? 200 : 500;
             var httpStatusDescription = status.IsHealthy || alwaysReturnOkStatusCode ? "OK" : "Internal Server Error";
 
-            return new MetricsEndpointResponse(json, JsonHealthChecks.HealthChecksMimeType, Encoding.UTF8, httpStatus, httpStatusDescription);
+            return new MetricsEndpointResponse(json, healthMimeType, Encoding.UTF8, httpStatus, httpStatusDescription);
         }
 
+        private static Func<HealthStatus, string> GetJsonHealthCreator(MetricsEndpointRequest request)
+        {
+            return IsJsonHealthV2(request)
+                ? (Func<HealthStatus, string>)JsonHealthChecksV2.BuildJson
+                : JsonHealthChecksV1.BuildJson;
+        }
+
+        private static string GetJsonHealthMimeType(MetricsEndpointRequest request)
+        {
+            return IsJsonHealthV2(request)
+                ? JsonHealthChecksV2.HealthChecksMimeType
+                : JsonHealthChecksV1.HealthChecksMimeType;
+        }
+
+        private static bool IsJsonHealthV2(MetricsEndpointRequest request)
+        {
+            string[] acceptHeader;
+            if (request.Headers.TryGetValue("Accept", out acceptHeader))
+            {
+                return acceptHeader.Contains(JsonHealthChecksV2.HealthChecksMimeType);
+            }
+            return false;
+        }
+
+        #endregion HealthChecks
+
+        #region MetricsData
+
         public static MetricsEndpointReports WithJsonV1Report(this MetricsEndpointReports reports, string endpoint)
         {
             return reports.WithEndpointReport(endpoint, GetJsonV1Response);
@@ -58,11 +98,6 @@ public static MetricsEndpointReports WithJsonReport(this MetricsEndpointReports
             return reports.WithEndpointReport(endpoint, GetJsonResponse);
         }
 
-        public static MetricsEndpointReports WithPing(this MetricsEndpointReports reports)
-        {
-            return reports.WithEndpointReport("/ping", (d, h, r) => new MetricsEndpointResponse("pong", "text/plain"));
-        }
-
         private static MetricsEndpointResponse GetJsonResponse(MetricsData data, Func<HealthStatus> healthStatus, MetricsEndpointRequest request)
         {
             string[] acceptHeader;
@@ -75,5 +110,12 @@ private static MetricsEndpointResponse GetJsonResponse(MetricsData data, Func<He
 
             return GetJsonV1Response(data, healthStatus, request);
         }
+
+        #endregion MetricsData
+
+        public static MetricsEndpointReports WithPing(this MetricsEndpointReports reports)
+        {
+            return reports.WithEndpointReport("/ping", (d, h, r) => new MetricsEndpointResponse("pong", "text/plain"));
+        }
     }
 }

Src/Metrics/Reporters/MetricsEndpointReports.cs

@@ -39,8 +39,9 @@ private void RegisterDefaultEndpoints()
         {
             this
                 .WithTextReport("/text")
+                .WithJsonHealthV1Report("/v1/health")
+                .WithJsonHealthV2Report("/v2/health")
                 .WithJsonHealthReport("/health")
-                .WithJsonHealthReport("/v1/health")
                 .WithJsonV1Report("/v1/json")
                 .WithJsonV2Report("/v2/json")
                 .WithJsonReport("/json")