feat: add response encoding to Options

Author: phnx47

src/Prometheus.Client.MetricServer/MetricServer.cs

@@ -87,7 +87,7 @@ public void Start()
                         options.Listen(IPAddress.Any, _options.Port, listenOptions => { listenOptions.UseHttps(_options.Certificate); });
                 })
                 .UseUrls($"http{(_options.Certificate != null ? "s" : "")}://{_options.Host}:{_options.Port}")
-                .ConfigureServices(services => { services.AddSingleton<IStartup>(new Startup(_options.CollectorRegistryInstance, _options.MapPath)); })
+                .ConfigureServices(services => { services.AddSingleton<IStartup>(new Startup(_options)); })
                 .UseSetting(WebHostDefaults.ApplicationKey, typeof(Startup).GetTypeInfo().Assembly.FullName)
                 .Build();
 
@@ -106,15 +106,11 @@ public void Stop()
 
         internal class Startup : IStartup
         {
-            private const string _contentType = "text/plain; version=0.0.4";
-            private readonly string _mapPath;
+            private readonly MetricServerOptions _options;
 
-            private readonly ICollectorRegistry _registry;
-
-            public Startup(ICollectorRegistry registry, string mapPath)
+            public Startup(MetricServerOptions options)
             {
-                _registry = registry;
-                _mapPath = mapPath;
+                _options = options;
 
                 var builder = new ConfigurationBuilder();
                 Configuration = builder.Build();
@@ -129,15 +125,20 @@ public IServiceProvider ConfigureServices(IServiceCollection services)
 
             public void Configure(IApplicationBuilder app)
             {
-                app.Map(_mapPath, coreapp =>
+                var contentType = "text/plain; version=0.0.4";
+
+                if (_options.ResponseEncoding != null)
+                    contentType += $"; charset={_options.ResponseEncoding.BodyName}";
+
+                app.Map(_options.MapPath, coreapp =>
                 {
                     coreapp.Run(async context =>
                     {
                         var response = context.Response;
-                        response.ContentType = _contentType;
+                        response.ContentType = contentType;
 
                         using var outputStream = response.Body;
-                        await ScrapeHandler.ProcessAsync(_registry, outputStream);
+                        await ScrapeHandler.ProcessAsync(_options.CollectorRegistryInstance, outputStream);
                     });
                 });
             }

src/Prometheus.Client.MetricServer/MetricServerOptions.cs

@@ -1,4 +1,5 @@
 using System.Security.Cryptography.X509Certificates;
+using System.Text;
 using Prometheus.Client.Collectors;
 
 namespace Prometheus.Client.MetricServer
@@ -37,5 +38,10 @@ public class MetricServerOptions
         ///     Use default collectors(dotnet and process stats)
         /// </summary>
         public bool UseDefaultCollectors { get; set; } = false;
+
+        /// <summary>
+        ///     Charset of text response.
+        /// </summary>
+        public Encoding ResponseEncoding { get; set; }
     }
 }

tests/Prometheus.Client.MetricServer.Tests/MetricServerTests.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Net;
 using System.Net.Http;
+using System.Text;
 using System.Threading.Tasks;
 using Prometheus.Client.Collectors;
 using Xunit;
@@ -125,7 +126,7 @@ public async Task Find_Metric()
         {
             var registry = new CollectorRegistry();
             var factory = new MetricFactory(registry);
-            var metricServer = new MetricServer(new MetricServerOptions { Port = _port, CollectorRegistryInstance = registry});
+            var metricServer = new MetricServer(new MetricServerOptions { Port = _port, CollectorRegistryInstance = registry });
 
             try
             {
@@ -179,12 +180,7 @@ public async Task Url_NotFound()
         public async Task Find_Default_Metric()
         {
             var registry = new CollectorRegistry();
-            var metricServer = new MetricServer(new MetricServerOptions
-            {
-                Port = _port,
-                CollectorRegistryInstance = registry,
-                UseDefaultCollectors = true
-            });
+            var metricServer = new MetricServer(new MetricServerOptions { Port = _port, CollectorRegistryInstance = registry, UseDefaultCollectors = true });
 
             try
             {
@@ -205,5 +201,33 @@ public async Task Find_Default_Metric()
                 metricServer.Stop();
             }
         }
+
+        [Fact]
+        public async Task Add_Encoding()
+        {
+            var metricServer = new MetricServer(new MetricServerOptions { Port = _port, ResponseEncoding = Encoding.UTF8 });
+
+            try
+            {
+                metricServer.Start();
+
+                const string help = "русский хелп";
+                var counter = Metrics.DefaultFactory.CreateCounter("test_counter", help);
+                counter.Inc();
+
+                using var httpClient = new HttpClient();
+                string response = await httpClient.GetStringAsync($"http://localhost:{_port}/metrics");
+                Assert.Contains(help, response);
+            }
+            catch (Exception ex)
+            {
+                _testOutputHelper.WriteLine(ex.ToString());
+                throw;
+            }
+            finally
+            {
+                metricServer.Stop();
+            }
+        }
     }
 }