Added a "LatestEvents" field to the FetchedInstanceHistory log (#1373)

* added the LastEvents field

* removed unnecessary usings

* updated the log event version

---------

Co-authored-by: Sophia Tevosyan <stevosyan@microsoft.com>

Author: sophiatev

src/DurableTask.AzureStorage/AnalyticsEventSource.cs

@@ -306,7 +306,7 @@ public void PoisonMessageDetected(
                 ExtensionVersion);
         }
 
-        [Event(EventIds.FetchedInstanceHistory, Level = EventLevel.Informational, Version = 4)]
+        [Event(EventIds.FetchedInstanceHistory, Level = EventLevel.Informational, Version = 5)]
         public void FetchedInstanceHistory(
             string Account,
             string TaskHub,
@@ -318,6 +318,7 @@ public void FetchedInstanceHistory(
             long LatencyMs,
             string ETag,
             DateTime LastCheckpointTime,
+            string LatestEvents,
             string AppName,
             string ExtensionVersion)
         {
@@ -333,6 +334,7 @@ public void FetchedInstanceHistory(
                 LatencyMs,
                 ETag ?? string.Empty,
                 LastCheckpointTime,
+                LatestEvents,
                 AppName,
                 ExtensionVersion);
         }

src/DurableTask.AzureStorage/Logging/LogEvents.cs

@@ -745,7 +745,8 @@ public FetchedInstanceHistory(
                 int requestCount,
                 long latencyMs,
                 string eTag,
-                DateTime lastCheckpointTime)
+                DateTime lastCheckpointTime,
+                string latestEvents)
             {
                 this.Account = account;
                 this.TaskHub = taskHub;
@@ -757,6 +758,7 @@ public FetchedInstanceHistory(
                 this.LatencyMs = latencyMs;
                 this.ETag = eTag;
                 this.LastCheckpointTime = lastCheckpointTime;
+                this.LatestEvents = latestEvents;
             }
 
             [StructuredLogField]
@@ -789,6 +791,9 @@ public FetchedInstanceHistory(
             [StructuredLogField]
             public DateTime LastCheckpointTime { get; }
 
+            [StructuredLogField]
+            public string LatestEvents { get; }
+
             public override EventId EventId => new EventId(
                 EventIds.FetchedInstanceHistory,
                 nameof(EventIds.FetchedInstanceHistory));
@@ -811,6 +816,7 @@ void IEventSourceEvent.WriteEventSource() => AnalyticsEventSource.Log.FetchedIns
                 this.LatencyMs,
                 this.ETag,
                 this.LastCheckpointTime,
+                this.LatestEvents,
                 Utils.AppName,
                 Utils.ExtensionVersion);
         }

src/DurableTask.AzureStorage/Logging/LogHelper.cs

@@ -261,7 +261,8 @@ internal void FetchedInstanceHistory(
             int requestCount,
             long latencyMs,
             string eTag,
-            DateTime lastCheckpointTime)
+            DateTime lastCheckpointTime,
+            string latestEvents)
         {
             var logEvent = new LogEvents.FetchedInstanceHistory(
                 account,
@@ -273,7 +274,8 @@ internal void FetchedInstanceHistory(
                 requestCount,
                 latencyMs,
                 eTag,
-                lastCheckpointTime);
+                lastCheckpointTime,
+                latestEvents);
             this.WriteStructuredLog(logEvent);
         }
 

src/DurableTask.AzureStorage/Tracking/AzureTableTrackingStore.cs

@@ -14,7 +14,6 @@
 namespace DurableTask.AzureStorage.Tracking
 {
     using System;
-    using System.Collections.Concurrent;
     using System.Collections.Generic;
     using System.Diagnostics;
     using System.Linq;
@@ -226,7 +225,8 @@ public override async Task<OrchestrationHistory> GetHistoryEventsAsync(string in
                 results.RequestCount,
                 results.ElapsedMilliseconds,
                 eTagValue?.ToString(),
-                checkpointCompletionTime);
+                checkpointCompletionTime,
+                string.Join(",", historyEvents.Skip(Math.Max(0, historyEvents.Count - 10)).Select(e => e.EventType.ToString())));
 
             return new OrchestrationHistory(historyEvents, checkpointCompletionTime, eTagValue, trackingStoreContext);
         }
@@ -264,7 +264,8 @@ async Task<IReadOnlyList<TableEntity>> QueryHistoryAsync(string filter, string i
                 results.RequestCount,
                 results.ElapsedMilliseconds,
                 eTag: string.Empty,
-                DateTime.MinValue);
+                DateTime.MinValue,
+                string.Join(",", entities.Skip(Math.Max(0, entities.Count - 10)).Select(e => e.GetString(nameof(HistoryEvent.EventType)))));
 
             return entities;
         }