Remove redundant Prometheus labels

Labels with data about which machine it is, and which job provided
the data are added by Prometheus itself.

OhmGraphite.Test/PrometheusTest.cs

@@ -12,7 +12,7 @@ namespace OhmGraphite.Test
         public async void PrometheusTestServer()
         {
             var collector = new TestSensorCreator();
-            var prometheusCollection = new PrometheusCollection(collector, "my-pc", Metrics.DefaultRegistry);
+            var prometheusCollection = new PrometheusCollection(collector, Metrics.DefaultRegistry);
             var mserver = new MetricServer("localhost", 21881);
             var server = new PrometheusServer(mserver, collector);
             try
@@ -22,7 +22,7 @@ namespace OhmGraphite.Test
                 var resp = await client.GetAsync("http://localhost:21881/metrics");
                 Assert.True(resp.IsSuccessStatusCode);
                 var content = await resp.Content.ReadAsStringAsync();
-                Assert.Contains("# HELP intelcpu_0_temperature_0 Metric reported by open hardware sensor", content);
+                Assert.Contains("# HELP ohm_temperature Metric reported by open hardware sensor", content);
             }
             finally
             {
@@ -34,7 +34,7 @@ namespace OhmGraphite.Test
         public async void PrometheusNicGuid()
         {
             var collector = new NicGuidSensor();
-            var prometheusCollection = new PrometheusCollection(collector, "my-pc", Metrics.DefaultRegistry);
+            var prometheusCollection = new PrometheusCollection(collector, Metrics.DefaultRegistry);
             var mserver = new MetricServer("localhost", 21882);
             var server = new PrometheusServer(mserver, collector);
             try

OhmGraphite/Program.cs

@@ -67,7 +67,7 @@ namespace OhmGraphite
             else if (config.Prometheus != null)
             {
                 Logger.Info($"Prometheus port: {config.Prometheus.Port}");
-                var prometheusCollection = new PrometheusCollection(collector, hostname, Metrics.DefaultRegistry);
+                var prometheusCollection = new PrometheusCollection(collector, Metrics.DefaultRegistry);
                 var server = new MetricServer(config.Prometheus.Host, config.Prometheus.Port);
                 return new PrometheusServer(server, collector);
             }

OhmGraphite/PrometheusCollection.cs

@@ -9,13 +9,11 @@ namespace OhmGraphite
     {
         private static readonly Logger Logger = LogManager.GetCurrentClassLogger();
         private readonly IGiveSensors _collector;
-        private readonly string _localHost;
         private MetricFactory _metrics;
 
-        public PrometheusCollection(IGiveSensors collector, string localHost, CollectorRegistry registry)
+        public PrometheusCollection(IGiveSensors collector, CollectorRegistry registry)
         {
             _collector = collector;
-            _localHost = localHost;
             registry.AddBeforeCollectCallback(UpdateMetrics);
             _metrics = Metrics.WithCustomRegistry(registry);
         }
@@ -32,8 +30,8 @@ namespace OhmGraphite
                 _metrics.CreateGauge(
                         "ohm_" + sensor.SensorType.ToString().ToLower(),
                         "Metric reported by open hardware sensor",
-                        "host", "app", "hardware", "hardware_type", "sensor", "sensor_index")
-                    .WithLabels(_localHost, "ohm", sensor.Hardware,
+                        "hardware", "hardware_type", "sensor", "sensor_index")
+                    .WithLabels(sensor.Hardware,
                         Enum.GetName(typeof(HardwareType), sensor.HardwareType),
                         sensor.Sensor,
                         sensor.SensorIndex.ToString())