Logging improvements to DiagnosticEventTableStorageRepository (#10996)

Author: cjaliaga

release_notes.md

@@ -2,4 +2,4 @@
 
 <!-- Please add your release notes in the following format:
 - My change description (#PR)
--->
+- Disable Diagnostic Events when Table Storage is not accessible (#10996)

src/WebJobs.Script.WebHost/Diagnostics/DiagnosticEventTableStorageRepository.Log.cs

@@ -0,0 +1,88 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.Extensions.Logging;
+
+namespace Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics
+{
+    public partial class DiagnosticEventTableStorageRepository
+    {
+        private static class Logger
+        {
+            private static readonly Action<ILogger, Exception> _serviceDisabledFailedToCreateClient =
+                LoggerMessage.Define(
+                    LogLevel.Warning,
+                    new EventId(1, nameof(ServiceDisabledFailedToCreateClient)),
+                    "We couldn’t initialize the Table Storage Client using the 'AzureWebJobsStorage' connection string. We are unable to record diagnostic events, so the diagnostic logging service is being stopped. Please check the 'AzureWebJobsStorage' connection string in Application Settings.");
+
+            private static readonly Action<ILogger, Exception> _serviceDisabledUnauthorizedClient =
+                LoggerMessage.Define(
+                    LogLevel.Warning,
+                    new EventId(2, nameof(ServiceDisabledUnauthorizedClient)),
+                    "We couldn’t access the Table service in the Azure Storage account defined by the 'AzureWebJobsStorage' setting. We are unable to record diagnostic events, so the diagnostic logging service is being stopped. Please ensure the connection string or managed identity has permissions to access the Table service and that any network rules allow connectivity. If you're using an identity-based connection, make sure it has been assigned the 'Storage Table Data Contributor' role.");
+
+            private static readonly Action<ILogger, Exception> _serviceDisabledUnableToConnectToStorage =
+                LoggerMessage.Define(
+                    LogLevel.Warning,
+                    new EventId(3, nameof(ServiceDisabledUnableToConnectToStorage)),
+                    "We couldn’t reach the Table service endpoint specified in the 'AzureWebJobsStorage' setting. We are unable to record diagnostic events, so the diagnostic logging service is being stopped. Please confirm network connectivity and endpoint accessibility.");
+
+            private static readonly Action<ILogger, string, Exception> _purgingDiagnosticEvents =
+                LoggerMessage.Define<string>(LogLevel.Debug, new EventId(4, nameof(PurgingDiagnosticEvents)), "Purging diagnostic events with versions older than '{currentEventVersion}'.");
+
+            private static readonly Action<ILogger, string, Exception> _deletingTableWithoutEventVersion =
+                LoggerMessage.Define<string>(LogLevel.Debug, new EventId(5, nameof(DeletingTableWithoutEventVersion)), "Deleting table '{tableName}' as it contains records without an EventVersion.");
+
+            private static readonly Action<ILogger, string, Exception> _deletingTableWithOutdatedEventVersion =
+                LoggerMessage.Define<string>(LogLevel.Debug, new EventId(6, nameof(DeletingTableWithOutdatedEventVersion)), "Deleting table '{tableName}' as it contains records with an outdated EventVersion.");
+
+            private static readonly Action<ILogger, Exception> _errorPurgingDiagnosticEventVersions =
+                LoggerMessage.Define(LogLevel.Error, new EventId(7, nameof(ErrorPurgingDiagnosticEventVersions)), "Error occurred when attempting to purge previous diagnostic event versions.");
+
+            private static readonly Action<ILogger, Exception> _unableToGetTableReference =
+                LoggerMessage.Define(LogLevel.Error, new EventId(8, nameof(UnableToGetTableReference)), "Unable to get table reference. Aborting write operation.");
+
+            private static readonly Action<ILogger, Exception> _unableToGetTableReferenceOrCreateTable =
+                LoggerMessage.Define(LogLevel.Error, new EventId(9, nameof(UnableToGetTableReferenceOrCreateTable)), "Unable to get table reference or create table. Aborting write operation.");
+
+            private static readonly Action<ILogger, Exception> _unableToWriteDiagnosticEvents =
+                LoggerMessage.Define(LogLevel.Error, new EventId(10, nameof(UnableToWriteDiagnosticEvents)), "Unable to write diagnostic events to table storage.");
+
+            private static readonly Action<ILogger, Exception> _primaryHostStateProviderNotAvailable =
+                LoggerMessage.Define(LogLevel.Debug, new EventId(11, nameof(PrimaryHostStateProviderNotAvailable)), "PrimaryHostStateProvider is not available. Skipping the check for primary host.");
+
+            private static readonly Action<ILogger, Exception> _stoppingFlushLogsTimer =
+                LoggerMessage.Define(LogLevel.Information, new EventId(12, nameof(StoppingFlushLogsTimer)), "Stopping the flush logs timer.");
+
+            private static readonly Action<ILogger, Exception> _queueingBackgroundTablePurge =
+                LoggerMessage.Define(LogLevel.Debug, new EventId(13, nameof(QueueingBackgroundTablePurge)), "Queueing background table purge.");
+
+            public static void ServiceDisabledFailedToCreateClient(ILogger logger) => _serviceDisabledFailedToCreateClient(logger, null);
+
+            public static void ServiceDisabledUnauthorizedClient(ILogger logger, Exception exception) => _serviceDisabledUnauthorizedClient(logger, exception);
+
+            public static void ServiceDisabledUnableToConnectToStorage(ILogger logger, Exception exception) => _serviceDisabledUnableToConnectToStorage(logger, exception);
+
+            public static void PurgingDiagnosticEvents(ILogger logger, string currentEventVersion) => _purgingDiagnosticEvents(logger, currentEventVersion, null);
+
+            public static void DeletingTableWithoutEventVersion(ILogger logger, string tableName) => _deletingTableWithoutEventVersion(logger, tableName, null);
+
+            public static void DeletingTableWithOutdatedEventVersion(ILogger logger, string tableName) => _deletingTableWithOutdatedEventVersion(logger, tableName, null);
+
+            public static void ErrorPurgingDiagnosticEventVersions(ILogger<DiagnosticEventTableStorageRepository> logger, Exception exception) => _errorPurgingDiagnosticEventVersions(logger, exception);
+
+            public static void UnableToGetTableReference(ILogger logger) => _unableToGetTableReference(logger, null);
+
+            public static void UnableToGetTableReferenceOrCreateTable(ILogger logger, Exception exception) => _unableToGetTableReferenceOrCreateTable(logger, exception);
+
+            public static void UnableToWriteDiagnosticEvents(ILogger logger, Exception exception) => _unableToWriteDiagnosticEvents(logger, exception);
+
+            public static void PrimaryHostStateProviderNotAvailable(ILogger logger) => _primaryHostStateProviderNotAvailable(logger, null);
+
+            public static void StoppingFlushLogsTimer(ILogger logger) => _stoppingFlushLogsTimer(logger, null);
+
+            public static void QueueingBackgroundTablePurge(ILogger logger) => _queueingBackgroundTablePurge(logger, null);
+        }
+    }
+}

src/WebJobs.Script.WebHost/Diagnostics/DiagnosticEventTableStorageRepository.cs

@@ -5,9 +5,12 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net;
 using System.Threading;
 using System.Threading.Tasks;
+using Azure;
 using Azure.Data.Tables;
+using Azure.Data.Tables.Models;
 using Microsoft.Azure.WebJobs.Host.Executors;
 using Microsoft.Azure.WebJobs.Hosting;
 using Microsoft.Azure.WebJobs.Logging;
@@ -17,7 +20,7 @@
 
 namespace Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics
 {
-    public class DiagnosticEventTableStorageRepository : IDiagnosticEventRepository, IDisposable
+    public partial class DiagnosticEventTableStorageRepository : IDiagnosticEventRepository, IDisposable
     {
         internal const string TableNamePrefix = "AzureFunctionsDiagnosticEvents";
         private const int LogFlushInterval = 1000 * 60 * 10; // 10 minutes
@@ -59,11 +62,41 @@ internal TableServiceClient TableClient
         {
             get
             {
-                if (!_environment.IsPlaceholderModeEnabled() && _tableClient == null && !_azureTableStorageProvider.TryCreateHostingTableServiceClient(out _tableClient))
+                if (_tableClient is null && !_environment.IsPlaceholderModeEnabled())
                 {
-                    _logger.LogWarning("An error occurred initializing the Table Storage Client. We are unable to record diagnostic events, so the diagnostic logging service is being stopped.");
-                    _isEnabled = false;
-                    StopTimer();
+                    if (!_azureTableStorageProvider.TryCreateHostingTableServiceClient(out _tableClient))
+                    {
+                        DisableService();
+                        Logger.ServiceDisabledFailedToCreateClient(_logger);
+                        return _tableClient;
+                    }
+
+                    try
+                    {
+                        // When using RBAC, we need "Storage Table Data Contributor" as we require to list, create and delete tables and query/insert/delete entities.
+                        // Testing permissions by listing tables, creating and deleting a test table.
+                        var testTable = _tableClient.GetTableClient($"{TableNamePrefix}Check");
+                        _ = TableStorageHelpers.TableExists(testTable, _tableClient);
+                        _ = testTable.CreateIfNotExists();
+                        _ = testTable.Delete();
+                    }
+                    catch (RequestFailedException rfe) when (rfe.Status == (int)HttpStatusCode.Conflict || rfe.ErrorCode == TableErrorCode.TableBeingDeleted)
+                    {
+                        // The table is being deleted or there could be a conflict for several instances initializing.
+                        // We can ignore this error as it is not a failure and we tested the permissions.
+                    }
+                    catch (RequestFailedException rfe) when (rfe.Status == (int)HttpStatusCode.Forbidden)
+                    {
+                        DisableService();
+                        Logger.ServiceDisabledUnauthorizedClient(_logger, rfe);
+                    }
+                    catch (Exception ex)
+                    {
+                        // We failed to connect to the table storage account. This could be due to a transient error or a configuration issue, such network issues.
+                        // We will disable the service.
+                        DisableService();
+                        Logger.ServiceDisabledUnableToConnectToStorage(_logger, ex);
+                    }
                 }
 
                 return _tableClient;
@@ -84,6 +117,13 @@ internal string HostId
 
         internal ConcurrentDictionary<string, DiagnosticEvent> Events => _events;
 
+        private void DisableService()
+        {
+            _isEnabled = false;
+            StopTimer();
+            _events.Clear();
+        }
+
         internal TableClient GetDiagnosticEventsTable(DateTime? now = null)
         {
             if (TableClient != null)
@@ -114,7 +154,7 @@ protected internal virtual async void OnFlushLogs(object state)
 
         private async Task PurgePreviousEventVersions()
         {
-            _logger.LogDebug("Purging diagnostic events with versions older than '{currentEventVersion}'.", DiagnosticEvent.CurrentEventVersion);
+            Logger.PurgingDiagnosticEvents(_logger, DiagnosticEvent.CurrentEventVersion);
 
             bool tableDeleted = false;
 
@@ -133,7 +173,7 @@ await Utility.InvokeWithRetriesAsync(async () =>
                             // Delete table if it doesn't have records with EventVersion
                             if (string.IsNullOrEmpty(record.EventVersion) == true)
                             {
-                                _logger.LogDebug("Deleting table '{tableName}' as it contains records without an EventVersion.", table.Name);
+                                Logger.DeletingTableWithoutEventVersion(_logger, table.Name);
                                 await table.DeleteAsync();
                                 tableDeleted = true;
                                 break;
@@ -142,7 +182,7 @@ await Utility.InvokeWithRetriesAsync(async () =>
                             // If the table does have EventVersion, query if it is an outdated version
                             if (string.Compare(DiagnosticEvent.CurrentEventVersion, record.EventVersion, StringComparison.Ordinal) > 0)
                             {
-                                _logger.LogDebug("Deleting table '{tableName}' as it contains records with an outdated EventVersion.", table.Name);
+                                Logger.DeletingTableWithOutdatedEventVersion(_logger, table.Name);
                                 await table.DeleteAsync();
                                 tableDeleted = true;
                                 break;
@@ -154,7 +194,7 @@ await Utility.InvokeWithRetriesAsync(async () =>
                 }
                 catch (Exception ex)
                 {
-                    _logger.LogError(ex, "Error occurred when attempting to purge previous diagnostic event versions.");
+                    Logger.ErrorPurgingDiagnosticEventVersions(_logger, ex);
                 }
             }, maxRetries: 5, retryInterval: TimeSpan.FromSeconds(5));
 
@@ -170,7 +210,7 @@ internal virtual async Task FlushLogs(TableClient table = null)
             // TableClient is initialized lazily and it will stop the timer that schedules flush logs whenever it fails to initialize.
             // We need to check if the TableClient is null before proceeding. This helps when the first time the property is accessed is as part of the FlushLogs method.
             // We should not have any events stored pending to be written since WriteDiagnosticEvent will check for an initialized TableClient.
-            if (_environment.IsPlaceholderModeEnabled() || TableClient is null)
+            if (_environment.IsPlaceholderModeEnabled() || TableClient is null || !IsEnabled())
             {
                 return;
             }
@@ -186,21 +226,29 @@ internal virtual async Task FlushLogs(TableClient table = null)
 
                 if (table == null)
                 {
-                    _logger.LogError("Unable to get table reference. Aborting write operation.");
-                    StopTimer();
+                    Logger.UnableToGetTableReference(_logger);
+                    DisableService();
                     return;
                 }
 
                 bool tableCreated = await TableStorageHelpers.CreateIfNotExistsAsync(table, TableClient, TableCreationMaxRetryCount);
                 if (tableCreated)
                 {
-                    _logger.LogDebug("Queueing background table purge.");
+                    Logger.QueueingBackgroundTablePurge(_logger);
                     TableStorageHelpers.QueueBackgroundTablePurge(table, TableClient, TableNamePrefix, _logger);
                 }
             }
+            catch (RequestFailedException ex) when (ex.Status == (int)HttpStatusCode.Forbidden)
+            {
+                // If we reach this point, we already checked for permissions on TableClient initialization. It is possible that the permissions changed after the initialization or any storage firewall/network configuration changed.
+                // We will log the error and disable the service.
+                Logger.UnableToGetTableReferenceOrCreateTable(_logger, ex);
+                DisableService();
+                Logger.ServiceDisabledUnauthorizedClient(_logger, ex);
+            }
             catch (Exception ex)
             {
-                _logger.LogError(ex, "Unable to get table reference or create table. Aborting write operation.");
+                Logger.UnableToGetTableReferenceOrCreateTable(_logger, ex);
                 // Clearing the memory cache to avoid memory build up.
                 _events.Clear();
                 return;
@@ -232,9 +280,18 @@ internal async Task ExecuteBatchAsync(ConcurrentDictionary<string, DiagnosticEve
                 await table.SubmitTransactionAsync(batch);
                 events.Clear();
             }
+            catch (RequestFailedException ex) when (ex.Status == (int)HttpStatusCode.Forbidden)
+            {
+                // If we reach this point, we already checked for permissions on TableClient initialization.
+                // It is possible that the permissions changed after the initialization, any firewall/network rules were changed or it's a custom role where we don't have permissions to write entities.
+                // We will log the error and disable the service.
+                Logger.UnableToWriteDiagnosticEvents(_logger, ex);
+                DisableService();
+                Logger.ServiceDisabledUnauthorizedClient(_logger, ex);
+            }
             catch (Exception ex)
             {
-                _logger.LogError(ex, "Unable to write diagnostic events to table storage.");
+                Logger.UnableToWriteDiagnosticEvents(_logger, ex);
             }
         }
 
@@ -275,7 +332,7 @@ private bool IsPrimaryHost()
             var primaryHostStateProvider = _serviceProvider?.GetService<IPrimaryHostStateProvider>();
             if (primaryHostStateProvider is null)
             {
-                _logger.LogDebug("PrimaryHostStateProvider is not available. Skipping the check for primary host.");
+                Logger.PrimaryHostStateProviderNotAvailable(_logger);
                 return false;
             }
 
@@ -284,7 +341,7 @@ private bool IsPrimaryHost()
 
         private void StopTimer()
         {
-            _logger.LogInformation("Stopping the flush logs timer.");
+            Logger.StoppingFlushLogsTimer(_logger);
             _flushLogsTimer?.Change(Timeout.Infinite, Timeout.Infinite);
         }
 

src/WebJobs.Script.WebHost/Helpers/TableStorageHelpers.cs

@@ -96,6 +96,8 @@ internal static async Task<IEnumerable<TableClient>> ListOldTablesAsync(TableCli
 
         internal static async Task<IEnumerable<TableClient>> ListTablesAsync(TableServiceClient tableClient, string tableNamePrefix)
         {
+            ArgumentNullException.ThrowIfNull(tableClient, nameof(tableClient));
+
             // Azure.Data.Tables doesn't have a direct way to list tables with a prefix so we need to do it manually
             var givenValue = tableNamePrefix + "{";
             AsyncPageable<TableItem> tablesQuery = tableClient.QueryAsync(p => p.Name.CompareTo(tableNamePrefix) >= 0 && p.Name.CompareTo(givenValue) <= 0);
@@ -120,5 +122,17 @@ internal static async Task<bool> TableExistAsync(TableClient table, TableService
 
             return false;
         }
+
+        internal static bool TableExists(TableClient table, TableServiceClient tableClient)
+        {
+            var query = tableClient.Query(p => p.Name == table.Name);
+
+            foreach (var item in query)
+            {
+                return true;
+            }
+
+            return false;
+        }
     }
 }