Removing prometheus-net dependency (#1526)

* Update README.md

* Update KubernetesClient.csproj

* Delete examples/prometheus directory

* Delete src/KubernetesClient/PrometheusHandler.cs

README.md

@@ -26,14 +26,11 @@ You should also be able to authenticate with the in-cluster service
 account using the `InClusterConfig` function shown below.
 
 ## Monitoring
-There is optional built-in metric generation for prometheus client metrics.
+Metrics are built in to HttpClient using System.Diagnostics.DiagnosticsSource.
-The exported metrics are:
+https://learn.microsoft.com/en-us/dotnet/core/diagnostics/built-in-metrics-system-net
 
-* `k8s_dotnet_request_total` - Counter of request, broken down by HTTP Method
+There are many ways these metrics can be consumed/exposed but that decision is up to the application, not KubernetesClient itself.
-* `k8s_dotnet_response_code_total` - Counter of responses, broken down by HTTP Method and response code
+https://learn.microsoft.com/en-us/dotnet/core/diagnostics/metrics-collection
-* `k8s_request_latency_seconds` - Latency histograms broken down by method, api group, api version and resource kind
-
-There is an example integrating these monitors in the examples/prometheus directory.
 
 ## Sample Code
 

examples/prometheus/Prometheus.cs

@@ -1,29 +0,0 @@
-using k8s;
-using Prometheus;
-using System;
-using System.Threading;
-
-namespace prom
-{
-    internal class Prometheus
-    {
-        private static void Main(string[] args)
-        {
-            var config = KubernetesClientConfiguration.BuildDefaultConfig();
-            var handler = new PrometheusHandler();
-            IKubernetes client = new Kubernetes(config, handler);
-
-            var server = new MetricServer(hostname: "localhost", port: 1234);
-            server.Start();
-
-            Console.WriteLine("Making requests!");
-            while (true)
-            {
-                client.CoreV1.ListNamespacedPod("default");
-                client.CoreV1.ListNode();
-                client.AppsV1.ListNamespacedDeployment("default");
-                Thread.Sleep(1000);
-            }
-        }
-    }
-}

examples/prometheus/prometheus.csproj

@@ -1,7 +0,0 @@
-<Project Sdk="Microsoft.NET.Sdk">
-
-  <PropertyGroup>
-    <OutputType>Exe</OutputType>
-  </PropertyGroup>
-
-</Project>

src/KubernetesClient/KubernetesClient.csproj

@@ -10,7 +10,6 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="prometheus-net" Version="8.2.1" />
         <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="7.1.2" />
         <PackageReference Include="IdentityModel.OidcClient" Version="5.2.1" />
         <PackageReference Include="Fractions" Version="7.3.0" />

src/KubernetesClient/PrometheusHandler.cs

@@ -1,55 +0,0 @@
-using Prometheus;
-using System.Net.Http;
-
-namespace k8s
-{
-    public class PrometheusHandler : DelegatingHandler
-    {
-        private const string PREFIX = "k8s_dotnet";
-        private readonly Counter requests = Metrics.CreateCounter(
-            $"{PREFIX}_request_total", "Number of requests sent by this client",
-            new CounterConfiguration
-            {
-                LabelNames = new[] { "method" },
-            });
-
-        private readonly Histogram requestLatency = Metrics.CreateHistogram(
-            $"{PREFIX}_request_latency_seconds", "Latency of requests sent by this client",
-            new HistogramConfiguration
-            {
-                LabelNames = new[] { "verb", "group", "version", "kind" },
-            });
-
-        private readonly Counter responseCodes = Metrics.CreateCounter(
-            $"{PREFIX}_response_code_total", "Number of response codes received by the client",
-            new CounterConfiguration
-            {
-                LabelNames = new[] { "method", "code" },
-            });
-
-        private readonly Gauge activeRequests = Metrics.CreateGauge(
-            $"{PREFIX}_active_requests", "Number of requests currently in progress",
-            new GaugeConfiguration
-            {
-                LabelNames = new[] { "method" },
-            });
-
-        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
-        {
-            if (request == null)
-            {
-                throw new ArgumentNullException(nameof(request));
-            }
-
-            var digest = KubernetesRequestDigest.Parse(request);
-            requests.WithLabels(digest.Verb).Inc();
-            using (activeRequests.WithLabels(digest.Verb).TrackInProgress())
-            using (requestLatency.WithLabels(digest.Verb, digest.ApiGroup, digest.ApiVersion, digest.Kind).NewTimer())
-            {
-                var resp = await base.SendAsync(request, cancellationToken).ConfigureAwait(false);
-                responseCodes.WithLabels(request.Method.ToString(), ((int)resp.StatusCode).ToString()).Inc();
-                return resp;
-            }
-        }
-    }
-}