Throw exception for scaling configuration invalid value (#450)

* Throw exception for scaling configuration invalid value

* Change Exception type

Author: AmeyaRele

src/TriggerBinding/SqlTriggerListener.cs

@@ -70,24 +70,17 @@ public SqlTriggerListener(string connectionString, string tableName, string user
             this._executor = executor ?? throw new ArgumentNullException(nameof(executor));
             this._logger = logger ?? throw new ArgumentNullException(nameof(logger));
             this._configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
-            int configuredMaxChangesPerWorker;
+            int? configuredMaxChangesPerWorker;
             // 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}");
 
-            // In case converting from string to int is not possible from the user input.
-            try
+            configuredMaxChangesPerWorker = configuration.GetValue<int?>(ConfigKey_SqlTrigger_MaxChangesPerWorker);
+            this._maxChangesPerWorker = configuredMaxChangesPerWorker ?? DefaultMaxChangesPerWorker;
+            if (this._maxChangesPerWorker <= 0)
             {
-                configuredMaxChangesPerWorker = configuration.GetValue<int>(ConfigKey_SqlTrigger_MaxChangesPerWorker);
-            }
-            catch (Exception ex)
-            {
-                this._logger.LogError($"Failed to resolve integer value from user configured setting '{ConfigKey_SqlTrigger_MaxChangesPerWorker}' due to exception: {ex.GetType()}. Exception message: {ex.Message}");
-                TelemetryInstance.TrackException(TelemetryErrorName.InvalidConfigurationValue, ex, this._telemetryProps);
-
-                configuredMaxChangesPerWorker = DefaultMaxChangesPerWorker;
+                throw new InvalidOperationException($"Invalid value for configuration setting '{ConfigKey_SqlTrigger_MaxChangesPerWorker}'. Ensure that the value is a positive integer.");
             }
-            this._maxChangesPerWorker = configuredMaxChangesPerWorker > 0 ? configuredMaxChangesPerWorker : DefaultMaxChangesPerWorker;
         }
 
         public void Cancel()

test/Unit/TriggerBinding/SqlTriggerListenerTests.cs

@@ -232,20 +232,12 @@ public void ScaleMonitorGetScaleStatus_UserConfiguredMaxChangesPerWorker_Respect
         [InlineData("-1")]
         [InlineData("0")]
         [InlineData("10000000000")]
-        public void ScaleMonitorGetScaleStatus_InvalidUserConfiguredMaxChangesPerWorker_UsesDefaultValue(string maxChangesPerWorker)
+        public void InvalidUserConfiguredMaxChangesPerWorker(string maxChangesPerWorker)
         {
-            (IScaleMonitor<SqlTriggerMetrics> monitor, _) = GetScaleMonitor(maxChangesPerWorker);
-
-            ScaleStatusContext context;
-            ScaleStatus scaleStatus;
-
-            context = GetScaleStatusContext(new int[] { 0, 0, 0, 0, 10000 }, 10);
-            scaleStatus = monitor.GetScaleStatus(context);
-            Assert.Equal(ScaleVote.None, scaleStatus.Vote);
+            (Mock<ILogger> mockLogger, List<string> logMessages) = CreateMockLogger();
+            Mock<IConfiguration> mockConfiguration = CreateMockConfiguration(maxChangesPerWorker);
 
-            context = GetScaleStatusContext(new int[] { 0, 0, 0, 0, 10001 }, 10);
-            scaleStatus = monitor.GetScaleStatus(context);
-            Assert.Equal(ScaleVote.ScaleOut, scaleStatus.Vote);
+            Assert.Throws<InvalidOperationException>(() => new SqlTriggerListener<object>("testConnectionString", "testTableName", "testUserFunctionId", Mock.Of<ITriggeredFunctionExecutor>(), mockLogger.Object, mockConfiguration.Object));
         }
 
         private static IScaleMonitor<SqlTriggerMetrics> GetScaleMonitor(string tableName, string userFunctionId)