Fallback to Host ID if WEBSITE_SITE_NAME isn't defined (#1178)

* Fall back to using Host ID if WEBSITE_SITE_NAME doesn't exist

* cleanup

* Pass in env vars to startup

* verify test fails

* try

* remove default site name settings

* Update comment

* update docs

Author: Charles-Gagnon

docs/BindingsOverview.md

@@ -20,6 +20,7 @@
       - [Sql\_Trigger\_MaxBatchSize](#sql_trigger_maxbatchsize)
       - [Sql\_Trigger\_PollingIntervalMs](#sql_trigger_pollingintervalms)
       - [Sql\_Trigger\_MaxChangesPerWorker](#sql_trigger_maxchangesperworker)
+      - [WEBSITE\_SITE\_NAME](#website_site_name)
     - [Scaling for Trigger Bindings](#scaling-for-trigger-bindings)
     - [Retry support for Trigger Bindings](#retry-support-for-trigger-bindings)
       - [Startup retries](#startup-retries)
@@ -154,11 +155,10 @@ The upper limit on the number of pending changes in the user table that are allo
 
 #### WEBSITE_SITE_NAME
 
-The unique name used in creating the lease tables. The local apps depend on this setting for creating unique leases tables, please give a unique name for each app.
+If this setting exists, it will be used to generate a unique identifier for the function that is used for tracking function state. If not specified, this unique identifier will be generated from the [IHostIdProvider.GetHostIdAsync](https://github.com/Azure/azure-webjobs-sdk/blob/dev/src/Microsoft.Azure.WebJobs.Host/Executors/IHostIdProvider.cs#L14).
 
 > **NOTE:**
 > * If the setting is re-used across apps, having the same function name could cause the functions to use the same lease tables and the function runs to not work as expected.
-> * If you have 2 different SQL trigger functions with same functionName locally, not having WEBSITE_SITE_NAME would mean that the same leasees table would be used for both triggers resulting in only one of the functions being triggered.
 > * This is a read-only variable that is provided by the Azure App service for deployed functions and the user provided value will be overridden. Refer to [Environment variables](https://learn.microsoft.com/azure/app-service/reference-app-settings?tabs=kudu%2Cdotnet#app-environment) for apps.
 
 ### Scaling for Trigger Bindings

docs/TriggerBinding.md

@@ -96,11 +96,12 @@ To find the name of the leases table associated with your function, look in the
 
 This log message is at the `Information` level, so make sure your log level is set correctly.
 
-NOTE: `FunctionId` is generated from a couple of inputs:
-   - The [WEBSITE_SITE_NAME](https://github.com/Azure/azure-functions-sql-extension/blob/main/docs/BindingsOverview.md#website_site_name) setting
-   - The name of the function
+NOTE: `FunctionId` is generated from the name of the function and either
 
-If either of these values are changed then a new FunctionId will be generated and result in the function starting over from the beginning, including creating a new Leases table.
+* The [WEBSITE_SITE_NAME](https://github.com/Azure/azure-functions-sql-extension/blob/main/docs/BindingsOverview.md#website_site_name) setting
+* [IHostIdProvider.GetHostIdAsync](https://github.com/Azure/azure-webjobs-sdk/blob/dev/src/Microsoft.Azure.WebJobs.Host/Executors/IHostIdProvider.cs#L14) as a fallback if the WEBSITE_SITE_NAME setting doesn't exist
+
+If either the name of the function or the `WEBSITE_SITE_NAME`/`GetHostIdAsync` values are changed then a new FunctionId will be generated and result in the function starting over from the beginning, including creating a new Leases table.
 
 This table is used to ensure that all changes are processed and that no change is processed more than once. This table consists of two groups of columns:
 

samples/samples-csharp/local.settings.json

@@ -4,7 +4,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "FUNCTIONS_WORKER_RUNTIME": "dotnet",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesCSharp",
     "Sp_SelectCost": "SelectProductsCost",
     "ProductCost": 100
   }

samples/samples-csx/local.settings.json

@@ -4,7 +4,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "FUNCTIONS_WORKER_RUNTIME": "dotnet",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesCsx",
     "Sp_SelectCost": "SelectProductsCost",
     "ProductCost": 100
   }

samples/samples-java/local.settings.json

@@ -4,7 +4,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "FUNCTIONS_WORKER_RUNTIME": "java",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesJava",
     "Sp_SelectCost": "SelectProductsCost",
     "ProductCost": 100
   }

samples/samples-js-v4/local.settings.json

@@ -4,7 +4,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "FUNCTIONS_WORKER_RUNTIME": "node",
     "AzureWebJobsFeatureFlags": "EnableWorkerIndexing",
-    "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesNodeV4"
+    "SqlConnectionString": ""
   }
 }

samples/samples-js/local.settings.json

@@ -4,7 +4,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "FUNCTIONS_WORKER_RUNTIME": "node",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesJavascript",
     "Sp_SelectCost": "SelectProductsCost",
     "ProductCost": 100
   }

samples/samples-outofproc/local.settings.json

@@ -4,7 +4,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesOOP",
     "Sp_SelectCost": "SelectProductsCost",
     "ProductCost": 100
   }

samples/samples-powershell/local.settings.json

@@ -5,7 +5,6 @@
     "FUNCTIONS_WORKER_RUNTIME": "powershell",
     "FUNCTIONS_WORKER_RUNTIME_VERSION" : "~7.2",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesPowershell",
     "Sp_SelectCost": "SelectProductsCost",
     "ProductCost": 100
   }

samples/samples-python-v2/local.settings.json

@@ -5,7 +5,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "AzureWebJobsFeatureFlags": "EnableWorkerIndexing",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesPythonV2",
     "PYTHON_ISOLATE_WORKER_DEPENDENCIES": "1"
   }
 }

samples/samples-python/local.settings.json

@@ -4,7 +4,6 @@
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
     "FUNCTIONS_WORKER_RUNTIME": "python",
     "SqlConnectionString": "",
-    "WEBSITE_SITE_NAME": "SamplesPython",
     "Sp_SelectCost": "SelectProductsCost",
     "ProductCost": 100
   }

src/SqlBindingUtilities.cs

@@ -54,21 +54,6 @@ public static string GetConnectionString(string connectionStringSetting, IConfig
             return connectionString;
         }
 
-        public static string GetWebSiteName(IConfiguration configuration)
-        {
-            if (configuration == null)
-            {
-                throw new ArgumentNullException(nameof(configuration));
-            }
-            string websitename = configuration.GetConnectionStringOrSetting(SqlBindingConstants.WEBSITENAME);
-            // We require a WEBSITE_SITE_NAME for avoiding duplicates if users use the same function name accross apps.
-            if (string.IsNullOrEmpty(websitename))
-            {
-                throw new ArgumentException($"WEBSITE_SITE_NAME cannot be null or empty in your function app settings, please update the setting with a string value. Please refer to https://github.com/Azure/azure-functions-sql-extension/blob/main/docs/BindingsOverview.md#website_site_name for more information.");
-            }
-            return websitename;
-        }
-
         /// <summary>
         /// Parses the parameter string into a list of parameters, where each parameter is separated by "," and has the form
         /// "@param1=param2". "@param1" is the parameter name to be used in the query or stored procedure, and param1 is the

src/TriggerBinding/SqlTriggerBinding.cs

@@ -78,9 +78,9 @@ public async Task<IListener> CreateListenerAsync(ListenerFactoryContext context)
         {
             _ = context ?? throw new ArgumentNullException(nameof(context), "Missing listener context");
 
-            string userFunctionId = this.GetUserFunctionId();
-            string oldUserFunctionId = await this.GetOldUserFunctionIdAsync();
-            return new SqlTriggerListener<T>(this._connectionString, this._tableName, this._leasesTableName, userFunctionId, oldUserFunctionId, context.Executor, this._sqlOptions, this._logger, this._configuration);
+            string websiteSiteNameFunctionId = this.GetWebsiteSiteNameFunctionId();
+            string hostIdFunctionId = await this.GetHostIdFunctionIdAsync();
+            return new SqlTriggerListener<T>(this._connectionString, this._tableName, this._leasesTableName, websiteSiteNameFunctionId, hostIdFunctionId, context.Executor, this._sqlOptions, this._logger, this._configuration);
         }
 
         public ParameterDescriptor ToParameterDescriptor()
@@ -94,18 +94,23 @@ public ParameterDescriptor ToParameterDescriptor()
         }
 
         /// <summary>
-        /// Returns an ID that uniquely identifies the user function.
+        /// Returns an ID that uniquely identifies the user function, based on the WEBSITE_SITE_NAME configuration value.
         ///
         /// We call the WEBSITE_SITE_NAME from the configuration and use that to create the hash of the
         /// user function id. Appending another hash of class+method in here ensures that if there
         /// are multiple user functions within the same process and tracking the same SQL table, then each one of them
         /// gets a separate view of the table changes.
         /// </summary>
-        private string GetUserFunctionId()
+        /// <returns>The function ID, or NULL if there isn't a config value for WEBSITE_SITE_NAME</returns>
+        private string GetWebsiteSiteNameFunctionId()
         {
             // Using read-only App name for the hash https://learn.microsoft.com/en-us/azure/app-service/reference-app-settings?tabs=kudu%2Cdotnet#app-environment
-            string websiteName = SqlBindingUtilities.GetWebSiteName(this._configuration);
-
+            string websiteName = this._configuration.GetConnectionStringOrSetting(SqlBindingConstants.WEBSITENAME);
+            if (string.IsNullOrEmpty(websiteName))
+            {
+                this._logger.LogWarning("WEBSITE_SITE_NAME configuration is not set, will fall back to using function ID based on the host ID. This will mean consumption plan scaling will not work as intended.");
+                return null;
+            }
             var methodInfo = (MethodInfo)this._parameter.Member;
             // Get the function name from FunctionName attribute for .NET functions and methodInfo.Name for non .Net
             string functionName = ((FunctionNameAttribute)methodInfo.GetCustomAttribute(typeof(FunctionNameAttribute)))?.Name ?? $"{methodInfo.Name}";
@@ -118,7 +123,7 @@ private string GetUserFunctionId()
         }
 
         /// <summary>
-        /// Returns the deprecated ID that was used to identify the user function.
+        /// Returns an ID that uniquely identifies the user function, based on the host ID.
         ///
         /// We call the WebJobs SDK library method to generate the host ID. The host ID is essentially a hash of the
         /// assembly name containing the user function(s). This ensures that if the user ever updates their application,
@@ -127,7 +132,7 @@ private string GetUserFunctionId()
         /// are multiple user functions within the same process and tracking the same SQL table, then each one of them
         /// gets a separate view of the table changes.
         /// </summary>
-        private async Task<string> GetOldUserFunctionIdAsync()
+        private async Task<string> GetHostIdFunctionIdAsync()
         {
             string hostId = await this._hostIdProvider.GetHostIdAsync(CancellationToken.None);