Forwarding the LanguageWorkerOptions from the host

to the job host scope and ensuring we use the provided instances.

src/WebJobs.Script/Description/FunctionDescriptorProvider.cs

@@ -181,20 +181,18 @@ private bool TryParseTriggerParameter(BindingMetadata metadata, out ParameterDes
 
         protected internal virtual void ValidateFunction(FunctionMetadata functionMetadata)
         {
-            HashSet<string> names = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            HashSet<string> names = new(StringComparer.OrdinalIgnoreCase);
             foreach (var binding in functionMetadata.Bindings)
             {
                 ValidateBinding(binding);
 
                 // Ensure no duplicate binding names
                 if (names.Contains(binding.Name))
                 {
-                    throw new InvalidOperationException(string.Format("Multiple bindings with name '{0}' discovered. Binding names must be unique.", binding.Name));
-                }
-                else
-                {
-                    names.Add(binding.Name);
+                    throw new InvalidOperationException($"{nameof(FunctionDescriptorProvider)}: Multiple bindings with name '{binding.Name}' discovered. Binding names must be unique.");
                 }
+
+                names.Add(binding.Name);
             }
 
             // Verify there aren't multiple triggers defined

src/WebJobs.Script/Host/WorkerFunctionMetadataProvider.cs

@@ -257,13 +257,11 @@ internal static FunctionMetadata ValidateBindings(IEnumerable<string> rawBinding
                 // Ensure no duplicate binding names exist
                 if (bindingNames.Contains(functionBinding.Name))
                 {
-                    throw new InvalidOperationException(string.Format("Multiple bindings with name '{0}' discovered. Binding names must be unique.", functionBinding.Name));
-                }
-                else
-                {
-                    bindingNames.Add(functionBinding.Name);
+                    throw new InvalidOperationException($"{nameof(WorkerFunctionDescriptorProvider)}: Multiple bindings with name '{functionBinding.Name}' discovered. Binding names must be unique.");
                 }
 
+                bindingNames.Add(functionBinding.Name);
+
                 // add binding to function.Bindings once validation is complete
                 function.Bindings.Add(functionBinding);
             }

src/WebJobs.Script/ScriptHostBuilderExtensions.cs

@@ -311,10 +311,13 @@ public static IHostBuilder AddScriptHostCore(this IHostBuilder builder, ScriptAp
                 // Configuration
                 services.AddSingleton<IOptions<ScriptApplicationHostOptions>>(new OptionsWrapper<ScriptApplicationHostOptions>(applicationHostOptions));
                 services.AddSingleton<IOptionsMonitor<ScriptApplicationHostOptions>>(new ScriptApplicationHostOptionsMonitor(applicationHostOptions));
+
+                // Forward th host LanguageWorkerOptions to the Job Host.
+                var languageWorkerOptions = applicationHostOptions.RootServiceProvider.GetService<IOptionsMonitor<LanguageWorkerOptions>>();
+                services.AddSingleton(languageWorkerOptions);
+                services.AddSingleton<IOptions<LanguageWorkerOptions>>((s) => new OptionsWrapper<LanguageWorkerOptions>(languageWorkerOptions.CurrentValue));
                 services.ConfigureOptions<ScriptJobHostOptionsSetup>();
                 services.ConfigureOptions<JobHostFunctionTimeoutOptionsSetup>();
-                // LanguageWorkerOptionsSetup should be registered in WebHostServiceCollection as well to enable starting worker processing in placeholder mode.
-                services.ConfigureOptions<LanguageWorkerOptionsSetup>();
                 services.AddOptions<WorkerConcurrencyOptions>();
                 services.ConfigureOptions<HttpWorkerOptionsSetup>();
                 services.ConfigureOptions<ManagedDependencyOptionsSetup>();
@@ -329,7 +332,11 @@ public static IHostBuilder AddScriptHostCore(this IHostBuilder builder, ScriptAp
 
                 services.AddSingleton<IFileLoggingStatusManager, FileLoggingStatusManager>();
 
-                if (!applicationHostOptions.HasParentScope)
+                if (applicationHostOptions.HasParentScope)
+                {
+                    services.ConfigureOptions<JobHostLanguageWorkerOptionsSetup>();
+                }
+                else
                 {
                     AddCommonServices(services);
                 }

src/WebJobs.Script/Workers/FunctionInvocationDispatcherFactory.cs

@@ -27,7 +27,7 @@ public FunctionInvocationDispatcherFactory(IOptions<ScriptJobHostOptions> script
             IHttpWorkerChannelFactory httpWorkerChannelFactory,
             IRpcWorkerChannelFactory rpcWorkerChannelFactory,
             IOptions<HttpWorkerOptions> httpWorkerOptions,
-            IOptionsMonitor<LanguageWorkerOptions> rpcWorkerOptions,
+            IOptionsMonitor<LanguageWorkerOptions> workerOptions,
             IEnvironment environment,
             IWebHostRpcWorkerChannelManager webHostLanguageWorkerChannelManager,
             IJobHostRpcWorkerChannelManager jobHostLanguageWorkerChannelManager,
@@ -54,7 +54,7 @@ public FunctionInvocationDispatcherFactory(IOptions<ScriptJobHostOptions> script
                 eventManager,
                 loggerFactory,
                 rpcWorkerChannelFactory,
-                rpcWorkerOptions,
+                workerOptions,
                 webHostLanguageWorkerChannelManager,
                 jobHostLanguageWorkerChannelManager,
                 managedDependencyOptions,

src/WebJobs.Script/Workers/Rpc/Configuration/LanguageWorkerOptionsSetup.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using Microsoft.Azure.WebJobs.Script.Diagnostics;
 using Microsoft.Azure.WebJobs.Script.Workers.Profiles;
 using Microsoft.Extensions.Configuration;
@@ -38,7 +39,7 @@ public LanguageWorkerOptionsSetup(IConfiguration configuration,
             _logger = loggerFactory.CreateLogger("Host.LanguageWorkerConfig");
         }
 
-        public void Configure(LanguageWorkerOptions options)
+        public virtual void Configure(LanguageWorkerOptions options)
         {
             string workerRuntime = _environment.GetEnvironmentVariable(RpcWorkerConstants.FunctionWorkerRuntimeSettingName);
 
@@ -56,4 +57,24 @@ public void Configure(LanguageWorkerOptions options)
             options.WorkerConfigs = configFactory.GetConfigs();
         }
     }
+
+    internal class JobHostLanguageWorkerOptionsSetup : IPostConfigureOptions<LanguageWorkerOptions>
+    {
+        private readonly ILoggerFactory _loggerFactory;
+
+        public JobHostLanguageWorkerOptionsSetup(ILoggerFactory loggerFactory)
+        {
+            _loggerFactory = loggerFactory;
+        }
+
+        public void PostConfigure(string name, LanguageWorkerOptions options)
+        {
+            var message = $"Call to configure {nameof(LanguageWorkerOptions)} from the JobHost scope. " +
+                $"If using {nameof(IOptions<LanguageWorkerOptions>)}, please use {nameof(IOptionsMonitor<LanguageWorkerOptions>)} instead.";
+            Debug.Fail(message);
+
+            var logger = _loggerFactory.CreateLogger("Host.LanguageWorkerConfig");
+            logger.LogInformation(message);
+        }
+    }
 }

src/WebJobs.Script/Workers/Rpc/FunctionRegistration/RpcFunctionInvocationDispatcher.cs

@@ -67,7 +67,7 @@ public RpcFunctionInvocationDispatcher(IOptions<ScriptJobHostOptions> scriptHost
             IScriptEventManager eventManager,
             ILoggerFactory loggerFactory,
             IRpcWorkerChannelFactory rpcWorkerChannelFactory,
-            IOptionsMonitor<LanguageWorkerOptions> languageWorkerOptions,
+            IOptionsMonitor<LanguageWorkerOptions> workerOptions,
             IWebHostRpcWorkerChannelManager webHostLanguageWorkerChannelManager,
             IJobHostRpcWorkerChannelManager jobHostLanguageWorkerChannelManager,
             IOptions<ManagedDependencyOptions> managedDependencyOptions,
@@ -83,7 +83,11 @@ public RpcFunctionInvocationDispatcher(IOptions<ScriptJobHostOptions> scriptHost
             _webHostLanguageWorkerChannelManager = webHostLanguageWorkerChannelManager;
             _jobHostLanguageWorkerChannelManager = jobHostLanguageWorkerChannelManager;
             _eventManager = eventManager;
-            _workerConfigs = languageWorkerOptions?.CurrentValue?.WorkerConfigs ?? throw new ArgumentNullException(nameof(languageWorkerOptions));
+
+            // The state of worker configuration and the LanguageWorkerOptions will match the lifetime of the JobHost and the
+            // RpcFunctionInvocationDispatcher. So, we can safely cache the workerConfigs and workerRuntime here.
+            // Using IOptionsMonitor here to get the same cached version used by other copmponents and avoid a new instance initialization.
+            _workerConfigs = workerOptions?.CurrentValue?.WorkerConfigs ?? throw new ArgumentNullException(nameof(workerOptions));
             _managedDependencyOptions = managedDependencyOptions ?? throw new ArgumentNullException(nameof(managedDependencyOptions));
             _logger = loggerFactory.CreateLogger<RpcFunctionInvocationDispatcher>();
             _rpcWorkerChannelFactory = rpcWorkerChannelFactory;

test/WebJobs.Script.Tests.Shared/TestHostBuilderExtensions.cs

@@ -69,6 +69,7 @@ public static IHostBuilder ConfigureDefaultTestWebScriptHost(this IHostBuilder b
             AddMockedSingleton<ISharedMemoryManager>(services);
             AddMockedSingleton<IFunctionDataCache>(services);
             AddMockedSingleton<IAzureBlobStorageProvider>(services);
+            services.ConfigureOptions<LanguageWorkerOptionsSetup>();
             services.AddSingleton<IDiagnosticEventRepository, TestDiagnosticEventRepository>();
             services.AddSingleton<IDiagnosticEventRepositoryFactory, TestDiagnosticEventRepositoryFactory>();
             services.AddSingleton<ISecretManagerProvider, TestSecretManagerProvider>();