Add Prometheus with 1 metric

Geekbot.net/Geekbot.net.csproj

@@ -44,6 +44,7 @@
     <PackageReference Include="NLog.Config" Version="4.6.8" />
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="3.1.1.2" />
     <PackageReference Include="PokeApi.NET" Version="1.1.2" />
+    <PackageReference Include="prometheus-net" Version="3.5.0" />
     <PackageReference Include="SharpRaven" Version="2.4.0" />
     <PackageReference Include="SumoLogic.Logging.NLog" Version="1.0.1.3" />
     <PackageReference Include="System.Net.Http" Version="4.3.4" />

Geekbot.net/Handlers.cs

@@ -15,6 +15,7 @@ using Geekbot.net.Lib.Logger;
 using Geekbot.net.Lib.ReactionListener;
 using Geekbot.net.Lib.UserRepository;
 using Microsoft.EntityFrameworkCore;
+using Prometheus;
 
 namespace Geekbot.net
 {
@@ -32,6 +33,9 @@ namespace Geekbot.net
         private readonly RestApplication _applicationInfo;
         private readonly List<ulong> _ignoredServers;
 
+        private readonly Counter _messageCounterPrometheus =
+            Metrics.CreateCounter("messages", "Number of discord messages", new CounterConfiguration() {LabelNames = new[] {"guild", "channel", "user"}});
+
         public Handlers(DatabaseInitializer databaseInitializer, IDiscordClient client, IGeekbotLogger logger, IAlmostRedis redis,
             IServiceProvider servicesProvider, CommandService commands, IUserRepository userRepository,
             IReactionListener reactionListener, RestApplication applicationInfo)
@@ -146,6 +150,8 @@ namespace Geekbot.net
                     _messageCounterDatabaseContext.SaveChanges();
                 }
 
+                _messageCounterPrometheus.WithLabels(channel.Guild.Id.ToString(), channel.Id.ToString(), message.Author.Id.ToString()).Inc();
+
                 if (message.Author.IsBot) return;
                 _logger.Information(LogSource.Message, message.Content, SimpleConextConverter.ConvertSocketMessage(message));
             }

Geekbot.net/Lib/RunParameters.cs

@@ -72,5 +72,14 @@ namespace Geekbot.net.Lib
         
         [Option("api-port", Default = "12995", HelpText = "Port on which the WebApi listens")]
         public string ApiPort { get; set; }
+        
+        /************************************
+         * Prometheus                       *
+         ************************************/
+        [Option("prometheus-host", Default = "localhost", HelpText = "Host on which the Prometheus Metric Server listens")]
+        public string PrometheusHost { get; set; }
+        
+        [Option("prometheus-port", Default = "12991", HelpText = "Port on which the Prometheus Metric Server listens")]
+        public string PrometheusPort { get; set; }
     }
 }

Geekbot.net/Program.cs

@@ -24,6 +24,7 @@ using Geekbot.net.Lib.UserRepository;
 using Geekbot.net.WebApi;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
+using Prometheus;
 using WikipediaApi;
 
 namespace Geekbot.net
@@ -185,6 +186,8 @@ namespace Geekbot.net
 
                     var webserver = _runParameters.DisableApi ? Task.Delay(10) : StartWebApi();
                     
+                    StartPrometheusServer();
+                    
                     _logger.Information(LogSource.Geekbot, "Done and ready for use");
 
                     await webserver;
@@ -211,5 +214,13 @@ namespace Geekbot.net
             WebApiStartup.StartWebApi(_logger, _runParameters, _commands, _databaseInitializer.Initialize(), _client, _globalSettings, highscoreManager);
             return Task.CompletedTask;
         }
+
+        private void StartPrometheusServer()
+        {
+            var port = int.Parse(_runParameters.PrometheusPort);
+            var server = new MetricServer(_runParameters.PrometheusHost, port);
+            server.Start();
+            _logger.Information(LogSource.Geekbot, $"Prometheus Metric Server running on {_runParameters.PrometheusHost}:{_runParameters.PrometheusPort}");
+        }
     }
 }