Filter Azure monitor logs when customer does not subscribe for the categories (#10982)

manikantanallagatla · Manikanta Nallagatla · web-flow · commit 534a66ebcf7b · 2025-06-12T09:01:34.000+05:30
* try logger changes

* address all comments

* spaces change

* correct filter

* clean code

* address comments

* Addres more comments

* Update tests

* Fix tests build

* address comments

* Address commments

* address comment

* Fix UTs

---------

Co-authored-by: Manikanta Nallagatla &lt;mnallagatla@microsoft.com&gt;
diff --git a/src/WebJobs.Script.WebHost/Diagnostics/AzureMonitorDiagnosticLogger.cs b/src/WebJobs.Script.WebHost/Diagnostics/AzureMonitorDiagnosticLogger.cs
@@ -29,7 +29,8 @@ public class AzureMonitorDiagnosticLogger : ILogger
         private readonly IEventGenerator _eventGenerator;
         private readonly IEnvironment _environment;
         private readonly IExternalScopeProvider _scopeProvider;
-        private AppServiceOptions _appServiceOptions;
+        private bool _isAzureMonitorLoggingEnabled;
+        private IOptionsMonitor<AppServiceOptions> _appServiceOptionsMonitor;
 
         public AzureMonitorDiagnosticLogger(string category, string hostInstanceId, IEventGenerator eventGenerator, IEnvironment environment, IExternalScopeProvider scopeProvider,
             HostNameProvider hostNameProvider, IOptionsMonitor<AppServiceOptions> appServiceOptionsMonitor)
@@ -40,10 +41,9 @@ public AzureMonitorDiagnosticLogger(string category, string hostInstanceId, IEve
             _environment = environment ?? throw new ArgumentNullException(nameof(environment));
             _scopeProvider = scopeProvider ?? throw new ArgumentNullException(nameof(scopeProvider));
             _hostNameProvider = hostNameProvider ?? throw new ArgumentNullException(nameof(hostNameProvider));
-            _ = appServiceOptionsMonitor ?? throw new ArgumentNullException(nameof(appServiceOptionsMonitor));
-
-            appServiceOptionsMonitor.OnChange(newOptions => _appServiceOptions = newOptions);
-            _appServiceOptions = appServiceOptionsMonitor.CurrentValue;
+            _appServiceOptionsMonitor = appServiceOptionsMonitor ?? throw new ArgumentNullException(nameof(appServiceOptionsMonitor));
+            UpdateAppServiceOptions(_appServiceOptionsMonitor.CurrentValue);
+            _appServiceOptionsMonitor.OnChange(UpdateAppServiceOptions);
 
             _roleInstance = _environment.GetInstanceId();
 
@@ -55,7 +55,7 @@ public AzureMonitorDiagnosticLogger(string category, string hostInstanceId, IEve
         public bool IsEnabled(LogLevel logLevel)
         {
             // We want to instantiate this Logger in placeholder mode to warm it up, but do not want to log anything.
-            return !string.IsNullOrEmpty(_hostNameProvider.Value) && !_environment.IsPlaceholderModeEnabled();
+            return _isAzureMonitorLoggingEnabled && !string.IsNullOrEmpty(_hostNameProvider.Value) && !_environment.IsPlaceholderModeEnabled();
         }
 
         public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
@@ -107,7 +107,7 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
             using (JsonTextWriter writer = new JsonTextWriter(sw) { Formatting = Formatting.None })
             {
                 writer.WriteStartObject();
-                WritePropertyIfNotNull(writer, "appName", _appServiceOptions.AppName);
+                WritePropertyIfNotNull(writer, "appName", _appServiceOptionsMonitor.CurrentValue.AppName);
                 WritePropertyIfNotNull(writer, "roleInstance", _roleInstance);
                 WritePropertyIfNotNull(writer, "message", formattedMessage);
                 WritePropertyIfNotNull(writer, "category", _category);
@@ -136,6 +136,11 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
             _eventGenerator.LogAzureMonitorDiagnosticLogEvent(logLevel, _hostNameProvider.Value, AzureMonitorOperationName, AzureMonitorCategoryName, _regionName, sw.ToString());
         }
 
+        private void UpdateAppServiceOptions(AppServiceOptions appServiceOptions)
+        {
+            _isAzureMonitorLoggingEnabled = !(_environment.IsConsumptionOnLegion() && !_appServiceOptionsMonitor.CurrentValue.IsAzureMonitorLoggingEnabled);
+        }
+
         private static void WritePropertyIfNotNull<T>(JsonTextWriter writer, string propertyName, T propertyValue)
         {
             if (propertyValue != null)
diff --git a/src/WebJobs.Script.WebHost/WebScriptHostBuilderExtension.cs b/src/WebJobs.Script.WebHost/WebScriptHostBuilderExtension.cs
@@ -25,11 +25,13 @@
 using Microsoft.Azure.WebJobs.Script.WebHost.Management;
 using Microsoft.Azure.WebJobs.Script.WebHost.Middleware;
 using Microsoft.Azure.WebJobs.Script.WebHost.Storage;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using static Microsoft.Azure.WebJobs.Script.Utility;
 
 namespace Microsoft.Azure.WebJobs.Script.WebHost
 {
@@ -91,6 +93,17 @@ public static IHostBuilder AddWebScriptHost(this IHostBuilder builder, IServiceP
                     loggingBuilder.AddWebJobsSystem<SystemLoggerProvider>();
                     if (environment.IsAzureMonitorEnabled())
                     {
+                        if (environment.IsConsumptionOnLegion())
+                        {
+                            loggingBuilder.Services.AddOptions<LoggerFilterOptions>()
+                                .Configure<IOptionsMonitor<AppServiceOptions>>((filters, options) =>
+                                {
+                                    filters.AddFilter<AzureMonitorDiagnosticLoggerProvider>((category, level) =>
+                                    {
+                                        return options.CurrentValue.IsAzureMonitorLoggingEnabled;
+                                    });
+                                });
+                        }
                         loggingBuilder.Services.AddSingleton<ILoggerProvider, AzureMonitorDiagnosticLoggerProvider>();
                     }
 
diff --git a/src/WebJobs.Script/Config/AppServiceOptions.cs b/src/WebJobs.Script/Config/AppServiceOptions.cs
@@ -12,5 +12,7 @@ public class AppServiceOptions
         public string RuntimeSiteName { get; set; }
 
         public string SlotName { get; set; }
+
+        public bool IsAzureMonitorLoggingEnabled { get; set; }
     }
 }
diff --git a/src/WebJobs.Script/Config/AppServiceOptionsSetup.cs b/src/WebJobs.Script/Config/AppServiceOptionsSetup.cs
@@ -2,6 +2,8 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using Microsoft.Extensions.Options;
+using static Microsoft.Azure.WebJobs.Script.EnvironmentSettingNames;
+using static Microsoft.Azure.WebJobs.Script.Utility;
 
 namespace Microsoft.Azure.WebJobs.Script.Configuration
 {
@@ -20,6 +22,7 @@ public void Configure(AppServiceOptions options)
             options.SubscriptionId = _environment.GetSubscriptionId() ?? string.Empty;
             options.RuntimeSiteName = _environment.GetRuntimeSiteName() ?? string.Empty;
             options.SlotName = _environment.GetSlotName() ?? string.Empty;
+            options.IsAzureMonitorLoggingEnabled = _environment.IsAzureMonitorEnabled();
         }
     }
 }
diff --git a/src/WebJobs.Script/Environment/EnvironmentExtensions.cs b/src/WebJobs.Script/Environment/EnvironmentExtensions.cs
@@ -11,6 +11,7 @@
 using Microsoft.Azure.WebJobs.Script.Description;
 using Microsoft.Azure.WebJobs.Script.Workers.Rpc;
 using static Microsoft.Azure.WebJobs.Script.EnvironmentSettingNames;
+using static Microsoft.Azure.WebJobs.Script.Utility;
 
 namespace Microsoft.Azure.WebJobs.Script
 {
@@ -69,13 +70,7 @@ public static bool IsEasyAuthEnabled(this IEnvironment environment)
         /// </summary>
         public static bool IsAzureMonitorEnabled(this IEnvironment environment)
         {
-            string value = environment.GetEnvironmentVariable(AzureMonitorCategories);
-            if (value == null)
-            {
-                return true;
-            }
-            string[] categories = value.Split(',');
-            return categories.Contains(ScriptConstants.AzureMonitorTraceCategory);
+            return IsAzureMonitorLoggingEnabled(environment.GetEnvironmentVariable(AzureMonitorCategories));
         }
 
         /// <summary>
@@ -337,7 +332,7 @@ public static bool IsLinuxConsumptionOnAtlas(this IEnvironment environment)
                    string.IsNullOrEmpty(environment.GetEnvironmentVariable(LegionServiceHost));
         }
 
-        private static bool IsConsumptionOnLegion(this IEnvironment environment)
+        public static bool IsConsumptionOnLegion(this IEnvironment environment)
         {
             return !environment.IsAppService() &&
                    (!string.IsNullOrEmpty(environment.GetEnvironmentVariable(ContainerName)) ||
diff --git a/src/WebJobs.Script/ScriptConstants.cs b/src/WebJobs.Script/ScriptConstants.cs
@@ -227,6 +227,7 @@ public static class ScriptConstants
         public const string ExtendedPlatformChannelNameUpper = "EXTENDED";
 
         public const string AzureMonitorTraceCategory = "FunctionAppLogs";
+        public const string DefaultAzureMonitorCategories = "None";
 
         public const string KubernetesManagedAppName = "K8SE_APP_NAME";
         public const string KubernetesManagedAppNamespace = "K8SE_APP_NAMESPACE";
diff --git a/src/WebJobs.Script/Utility.cs b/src/WebJobs.Script/Utility.cs
@@ -1145,6 +1145,22 @@ public static bool TryReadAsBool(IDictionary<string, object> properties, string
             return result = false;
         }
 
+        public static bool IsAzureMonitorLoggingEnabled(string azureMonitorcategoriesSubscribed)
+        {
+            if (azureMonitorcategoriesSubscribed == null)
+            {
+                return true;
+            }
+            if (string.Equals(ScriptConstants.DefaultAzureMonitorCategories, azureMonitorcategoriesSubscribed, StringComparison.Ordinal))
+            {
+                // Default value for the env variable is None.
+                // This is set when customer does not subscribe any category.
+                return false;
+            }
+            string[] categories = azureMonitorcategoriesSubscribed.Split(',');
+            return categories.Contains(ScriptConstants.AzureMonitorTraceCategory);
+        }
+
         private class FilteredExpandoObjectConverter : ExpandoObjectConverter
         {
             public override bool CanWrite => true;
diff --git a/test/WebJobs.Script.Tests/Eventing/DiagnosticLoggerTests.cs b/test/WebJobs.Script.Tests/Eventing/DiagnosticLoggerTests.cs
@@ -206,35 +206,31 @@ public void Log_Sanitizes()
             Assert.True(JToken.DeepEquals(actual, expected), $"Actual: {actual.ToString()}{Environment.NewLine}Expected: {expected.ToString()}");
         }
 
-        [Fact]
-        public void Log_DisabledIfPlaceholder()
+        [Theory]
+        [InlineData(EnvironmentSettingNames.AzureWebsitePlaceholderMode, "1", false, false, false)] // Placeholder
+        [InlineData(EnvironmentSettingNames.AzureWebsitePlaceholderMode, "1", true, false, false)] // Placeholder
+        [InlineData(EnvironmentSettingNames.AzureWebsiteHostName, null, false, false, false)] // NoSiteName
+        [InlineData(EnvironmentSettingNames.AzureWebsiteHostName, null, true, false, false)] // NoSiteName
+        [InlineData(EnvironmentSettingNames.AzureWebsiteHostName, "host", false, false, true)]
+        [InlineData(EnvironmentSettingNames.AzureWebsiteHostName, "host", true, false, false)]
+        [InlineData(EnvironmentSettingNames.AzureWebsiteHostName, "host", true, true, true)]
+        public void Log_IsEnabled(string envVariableName, string envVariableVale, bool isConsumptionOnLegion, bool isAzureMonitorEnabled,  bool isDisabled)
         {
-            string message = "TestMessage";
             string functionInvocationId = Guid.NewGuid().ToString();
             string activityId = Guid.NewGuid().ToString();
 
-            _environment.SetEnvironmentVariable(EnvironmentSettingNames.AzureWebsitePlaceholderMode, "1");
-
-            _logger.LogInformation(message);
-
-            Assert.False(_logger.IsEnabled(LogLevel.Information));
-            _mockEventGenerator.Verify(m => m.LogAzureMonitorDiagnosticLogEvent(It.IsAny<LogLevel>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never);
-        }
-
-        [Fact]
-        public void Log_DisabledIfNoSiteName()
-        {
-            string message = "TestMessage";
-            string functionInvocationId = Guid.NewGuid().ToString();
-            string activityId = Guid.NewGuid().ToString();
-            _environment.SetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteHostName, null);
-
-            // Recreate the logger was we cache the site name in the constructor
-            ILogger logger = new AzureMonitorDiagnosticLogger(_category, _hostInstanceId, _mockEventGenerator.Object, _environment, new LoggerExternalScopeProvider(), _hostNameProvider, _appServiceOptionsWrapper);
+            _environment.SetEnvironmentVariable(envVariableName, envVariableVale);
+            if (isConsumptionOnLegion)
+            {
+                _environment.SetEnvironmentVariable(EnvironmentSettingNames.AzureWebsiteInstanceId, string.Empty);
+                _environment.SetEnvironmentVariable(EnvironmentSettingNames.ContainerName, "containername");
+                _environment.SetEnvironmentVariable(EnvironmentSettingNames.LegionServiceHost, "legionhost");
+            }
 
-            logger.LogInformation(message);
+            _appServiceOptionsWrapper.CurrentValue.IsAzureMonitorLoggingEnabled = isAzureMonitorEnabled;
+            _appServiceOptionsWrapper.InvokeChanged();
 
-            Assert.False(logger.IsEnabled(LogLevel.Information));
+            Assert.Equal(isDisabled, _logger.IsEnabled(LogLevel.Information));
             _mockEventGenerator.Verify(m => m.LogAzureMonitorDiagnosticLogEvent(It.IsAny<LogLevel>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never);
         }
 
diff --git a/test/WebJobs.Script.Tests/Extensions/EnvironmentExtensionsTests.cs b/test/WebJobs.Script.Tests/Extensions/EnvironmentExtensionsTests.cs
@@ -62,6 +62,8 @@ public void IsVMSS_RetrunsExpectedResult(string roleInstanceId, bool expected)
         [InlineData(null, true)]
         [InlineData("", false)]
         [InlineData("Foo,FunctionAppLogs,Bar", true)]
+        [InlineData("FunctionAppLogs", true)]
+        [InlineData("None", false)]
         [InlineData("Foo,Bar", false)]
         public void IsAzureMonitorEnabled_ReturnsExpectedResult(string value, bool expected)
         {

Original file line number	Diff line number	Diff line change
`@@ -12,5 +12,7 @@ public class AppServiceOptions`
`12`	`12`	`public string RuntimeSiteName { get; set; }`
`13`	`13`
`14`	`14`	`public string SlotName { get; set; }`
	`15`	`+`
	`16`	`+ public bool IsAzureMonitorLoggingEnabled { get; set; }`
`15`	`17`	`}`
`16`	`18`	`}`
Original file line number	Diff line number	Diff line change
`@@ -2,6 +2,8 @@`
`2`	`2`	`// Licensed under the MIT License. See License.txt in the project root for license information.`
`3`	`3`
`4`	`4`	`using Microsoft.Extensions.Options;`
	`5`	`+using static Microsoft.Azure.WebJobs.Script.EnvironmentSettingNames;`
	`6`	`+using static Microsoft.Azure.WebJobs.Script.Utility;`
`5`	`7`
`6`	`8`	`namespace Microsoft.Azure.WebJobs.Script.Configuration`
`7`	`9`	`{`
`@@ -20,6 +22,7 @@ public void Configure(AppServiceOptions options)`
`20`	`22`	`options.SubscriptionId = _environment.GetSubscriptionId() ?? string.Empty;`
`21`	`23`	`options.RuntimeSiteName = _environment.GetRuntimeSiteName() ?? string.Empty;`
`22`	`24`	`options.SlotName = _environment.GetSlotName() ?? string.Empty;`
	`25`	`+ options.IsAzureMonitorLoggingEnabled = _environment.IsAzureMonitorEnabled();`
`23`	`26`	`}`
`24`	`27`	`}`
`25`	`28`	`}`
Original file line number	Diff line number	Diff line change
`@@ -11,6 +11,7 @@`
`11`	`11`	`using Microsoft.Azure.WebJobs.Script.Description;`
`12`	`12`	`using Microsoft.Azure.WebJobs.Script.Workers.Rpc;`
`13`	`13`	`using static Microsoft.Azure.WebJobs.Script.EnvironmentSettingNames;`
	`14`	`+using static Microsoft.Azure.WebJobs.Script.Utility;`
`14`	`15`
`15`	`16`	`namespace Microsoft.Azure.WebJobs.Script`
`16`	`17`	`{`
`@@ -69,13 +70,7 @@ public static bool IsEasyAuthEnabled(this IEnvironment environment)`
`69`	`70`	`/// </summary>`
`70`	`71`	`public static bool IsAzureMonitorEnabled(this IEnvironment environment)`
`71`	`72`	`{`
`72`		`- string value = environment.GetEnvironmentVariable(AzureMonitorCategories);`
`73`		`- if (value == null)`
`74`		`- {`
`75`		`- return true;`
`76`		`- }`
`77`		`- string[] categories = value.Split(',');`
`78`		`- return categories.Contains(ScriptConstants.AzureMonitorTraceCategory);`
	`73`	`+ return IsAzureMonitorLoggingEnabled(environment.GetEnvironmentVariable(AzureMonitorCategories));`
`79`	`74`	`}`
`80`	`75`
`81`	`76`	`/// <summary>`
`@@ -337,7 +332,7 @@ public static bool IsLinuxConsumptionOnAtlas(this IEnvironment environment)`
`337`	`332`	`string.IsNullOrEmpty(environment.GetEnvironmentVariable(LegionServiceHost));`
`338`	`333`	`}`
`339`	`334`
`340`		`- private static bool IsConsumptionOnLegion(this IEnvironment environment)`
	`335`	`+ public static bool IsConsumptionOnLegion(this IEnvironment environment)`
`341`	`336`	`{`
`342`	`337`	`return !environment.IsAppService() &&`
`343`	`338`	`(!string.IsNullOrEmpty(environment.GetEnvironmentVariable(ContainerName)) \|\|`
Original file line number	Diff line number	Diff line change
`@@ -62,6 +62,8 @@ public void IsVMSS_RetrunsExpectedResult(string roleInstanceId, bool expected)`
`62`	`62`	`[InlineData(null, true)]`
`63`	`63`	`[InlineData("", false)]`
`64`	`64`	`[InlineData("Foo,FunctionAppLogs,Bar", true)]`
	`65`	`+ [InlineData("FunctionAppLogs", true)]`
	`66`	`+ [InlineData("None", false)]`
`65`	`67`	`[InlineData("Foo,Bar", false)]`
`66`	`68`	`public void IsAzureMonitorEnabled_ReturnsExpectedResult(string value, bool expected)`
`67`	`69`	`{`