Validate monitor config values and send max changes configuration on startup (#467)

* Validate monitor config values and send max changes configuration on startup

* Add enum values

Author: Charles-Gagnon

src/Telemetry/Telemetry.cs

@@ -362,6 +362,7 @@ public enum TelemetryPropertyName
         ExceptionType,
         HasIdentityColumn,
         HasConfiguredBatchSize,
+        HasConfiguredMaxChangesPerWorker,
         HasConfiguredPollingInterval,
         LeasesTableName,
         QueryType,
@@ -392,6 +393,7 @@ public enum TelemetryMeasureName
         GetPrimaryKeysDurationMs,
         GetUnprocessedChangesDurationMs,
         InsertGlobalStateTableRowDurationMs,
+        MaxChangesPerWorker,
         PollingIntervalMs,
         ReleaseLeasesDurationMs,
         RetryAttemptNumber,

src/TriggerBinding/SqlTableChangeMonitor.cs

@@ -130,19 +130,26 @@ public SqlTableChangeMonitor(
             int? configuredBatchSize = configuration.GetValue<int?>(ConfigKey_SqlTrigger_BatchSize);
             int? configuredPollingInterval = configuration.GetValue<int?>(ConfigKey_SqlTrigger_PollingInterval);
             this._batchSize = configuredBatchSize ?? this._batchSize;
+            if (this._batchSize <= 0)
+            {
+                throw new InvalidOperationException($"Invalid value for configuration setting '{ConfigKey_SqlTrigger_BatchSize}'. Ensure that the value is a positive integer.");
+            }
             this._pollingIntervalInMs = configuredPollingInterval ?? this._pollingIntervalInMs;
-            var monitorStartProps = new Dictionary<TelemetryPropertyName, string>(telemetryProps)
+            if (this._pollingIntervalInMs <= 0)
             {
-                { TelemetryPropertyName.HasConfiguredBatchSize, (configuredBatchSize != null).ToString() },
-                { TelemetryPropertyName.HasConfiguredPollingInterval, (configuredPollingInterval != null).ToString() },
-            };
+                throw new InvalidOperationException($"Invalid value for configuration setting '{ConfigKey_SqlTrigger_PollingInterval}'. Ensure that the value is a positive integer.");
+            }
             TelemetryInstance.TrackEvent(
                 TelemetryEventName.TriggerMonitorStart,
-                monitorStartProps,
+                new Dictionary<TelemetryPropertyName, string>(telemetryProps) {
+                        { TelemetryPropertyName.HasConfiguredBatchSize, (configuredBatchSize != null).ToString() },
+                        { TelemetryPropertyName.HasConfiguredPollingInterval, (configuredPollingInterval != null).ToString() },
+                },
                 new Dictionary<TelemetryMeasureName, double>() {
                     { TelemetryMeasureName.BatchSize, this._batchSize },
                     { TelemetryMeasureName.PollingIntervalMs, this._pollingIntervalInMs }
-            });
+                }
+            );
 
             // Prep search-conditions that will be used besides WHERE clause to match table rows.
             this._rowMatchConditions = Enumerable.Range(0, this._batchSize)

src/TriggerBinding/SqlTriggerListener.cs

@@ -47,6 +47,7 @@ internal sealed class SqlTriggerListener<T> : IListener, IScaleMonitor<SqlTrigge
 
         private readonly IDictionary<TelemetryPropertyName, string> _telemetryProps = new Dictionary<TelemetryPropertyName, string>();
         private readonly int _maxChangesPerWorker;
+        private readonly bool _hasConfiguredMaxChangesPerWorker = false;
 
         private SqlTableChangeMonitor<T> _changeMonitor;
         private int _listenerState = ListenerNotStarted;
@@ -74,13 +75,13 @@ public SqlTriggerListener(string connectionString, string tableName, string user
             // Do not convert the scale-monitor ID to lower-case string since SQL table names can be case-sensitive
             // depending on the collation of the current database.
             this._scaleMonitorDescriptor = new ScaleMonitorDescriptor($"{userFunctionId}-SqlTrigger-{tableName}");
-
             configuredMaxChangesPerWorker = configuration.GetValue<int?>(ConfigKey_SqlTrigger_MaxChangesPerWorker);
             this._maxChangesPerWorker = configuredMaxChangesPerWorker ?? DefaultMaxChangesPerWorker;
             if (this._maxChangesPerWorker <= 0)
             {
                 throw new InvalidOperationException($"Invalid value for configuration setting '{ConfigKey_SqlTrigger_MaxChangesPerWorker}'. Ensure that the value is a positive integer.");
             }
+            this._hasConfiguredMaxChangesPerWorker = configuredMaxChangesPerWorker != null;
         }
 
         public void Cancel()
@@ -105,7 +106,15 @@ public async Task StartAsync(CancellationToken cancellationToken)
             }
 
             this.InitializeTelemetryProps();
-            TelemetryInstance.TrackEvent(TelemetryEventName.StartListenerStart, this._telemetryProps);
+            TelemetryInstance.TrackEvent(
+                TelemetryEventName.StartListenerStart,
+                new Dictionary<TelemetryPropertyName, string>(this._telemetryProps) {
+                        { TelemetryPropertyName.HasConfiguredMaxChangesPerWorker, this._hasConfiguredMaxChangesPerWorker.ToString() }
+                },
+                new Dictionary<TelemetryMeasureName, double>() {
+                    { TelemetryMeasureName.MaxChangesPerWorker, this._maxChangesPerWorker }
+                }
+            );
 
             try
             {