Added descriptions for metric instruments

Author: ramonsmits

src/ServiceControl.Audit/Auditing/AuditIngestion.cs

@@ -266,12 +266,12 @@ async Task Loop()
         readonly IAuditIngestionUnitOfWorkFactory unitOfWorkFactory;
         readonly Settings settings;
         readonly Channel<MessageContext> channel;
-        readonly Histogram<long> auditBatchSize = Telemetry.Meter.CreateHistogram<long>(Telemetry.CreateInstrumentName("ingestion", "batch_size"));
-        readonly Histogram<double> auditBatchDuration = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "batch_duration"), unit: "ms");
-        readonly Histogram<double> messageSize = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "message_size"), unit: "kilobytes");
-        readonly Counter<long> ingestedMessagesCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "count"));
-        readonly Histogram<long> consecutiveBatchFailuresCounter = Telemetry.Meter.CreateHistogram<long>(Telemetry.CreateInstrumentName("ingestion", "consecutive_batch_failures"), unit: "count");
-        readonly Histogram<double> ingestionDuration = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "duration"), unit: "ms");
+        readonly Histogram<long> auditBatchSize = Telemetry.Meter.CreateHistogram<long>(Telemetry.CreateInstrumentName("ingestion", "batch_size"), description: "Audit ingestion average batch size");
+        readonly Histogram<double> auditBatchDuration = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "batch_duration"), unit: "ms", "Average audit message batch processing duration");
+        readonly Histogram<double> messageSize = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "message_size"), unit: "kilobytes", description: "Average audit message body size");
+        readonly Counter<long> ingestedMessagesCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "count"), description: "Successful ingested audit message count");
+        readonly Histogram<long> consecutiveBatchFailuresCounter = Telemetry.Meter.CreateHistogram<long>(Telemetry.CreateInstrumentName("ingestion", "consecutive_batch_failures"), unit: "count", description: "Consecutive audit ingestion batch failure");
+        readonly Histogram<double> ingestionDuration = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "duration"), unit: "ms", description: "Average incoming audit message processing duration");
         readonly Watchdog watchdog;
         readonly Task ingestionWorker;
         readonly IHostApplicationLifetime applicationLifetime;

src/ServiceControl.Audit/Auditing/AuditIngestionFaultPolicy.cs

@@ -104,8 +104,8 @@ void WriteToEventLog(string message)
             EventLog.WriteEntry(EventSourceCreator.SourceName, message, EventLogEntryType.Error);
         }
 
-        readonly Counter<long> retryCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "retry"));
-        readonly Counter<long> failedCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "failed"));
+        readonly Counter<long> retryCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "retry"), description: "Audit ingestion retries count");
+        readonly Counter<long> failedCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "failed"), description: "Audit ingestion failure count");
 
         static readonly ILog log = LogManager.GetLogger<AuditIngestionFaultPolicy>();
     }

src/ServiceControl.Audit/Auditing/AuditIngestor.cs

@@ -131,7 +131,7 @@ public async Task VerifyCanReachForwardingAddress()
         readonly Settings settings;
         readonly Lazy<IMessageDispatcher> messageDispatcher;
         readonly string logQueueAddress;
-        readonly Counter<long> forwardedMessagesCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "forwarded_count"));
+        readonly Counter<long> forwardedMessagesCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "forwarded_count"), description: "Audit ingestion forwarded message count");
 
         static readonly ILog Log = LogManager.GetLogger<AuditIngestor>();
     }

src/ServiceControl.Audit/Auditing/AuditPersister.cs

@@ -105,9 +105,9 @@ public async Task<IReadOnlyList<MessageContext>> Persist(IReadOnlyList<MessageCo
 
                     try
                     {
-                        // this can throw even though dispose is never supposed to throw
                         using (new DurationRecorder(commitDuration))
                         {
+                            // this can throw even though dispose is never supposed to throw
                             await unitOfWork.DisposeAsync();
                         }
                     }
@@ -252,9 +252,9 @@ await messageDispatcher.Value.Dispatch(new TransportOperations(messagesToEmit.To
             }
         }
 
-        readonly Counter<long> storedAuditsCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "audits_count"));
-        readonly Counter<long> storedSagasCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "sagas_count"));
-        readonly Histogram<double> commitDuration = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "commit_duration"), unit: "ms");
+        readonly Counter<long> storedAuditsCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "audits_count"), description: "Stored audit message count");
+        readonly Counter<long> storedSagasCounter = Telemetry.Meter.CreateCounter<long>(Telemetry.CreateInstrumentName("ingestion", "sagas_count"), description: "Stored saga state count");
+        readonly Histogram<double> commitDuration = Telemetry.Meter.CreateHistogram<double>(Telemetry.CreateInstrumentName("ingestion", "commit_duration"), unit: "ms", description: "Storage unit of work commit duration");
 
         static readonly ILog Logger = LogManager.GetLogger<AuditPersister>();
     }