public async Task CreateAsync_SkipsDisabledFunctions(Type jobType, string methodName)
        {
            Environment.SetEnvironmentVariable("EnvironmentSettingTrue", "True");

            Mock<IFunctionDefinition> mockFunctionDefinition = new Mock<IFunctionDefinition>();
            Mock<IFunctionInstanceFactory> mockInstanceFactory = new Mock<IFunctionInstanceFactory>(MockBehavior.Strict);
            Mock<IListenerFactory> mockListenerFactory = new Mock<IListenerFactory>(MockBehavior.Strict);
            SingletonManager singletonManager = new SingletonManager();
            TestTraceWriter traceWriter = new TestTraceWriter(TraceLevel.Verbose);

            // create a bunch of function definitions that are disabled
            List<FunctionDefinition> functions = new List<FunctionDefinition>();
            FunctionDescriptor descriptor = new FunctionDescriptor
            {
                Method = jobType.GetMethod(methodName, BindingFlags.Public | BindingFlags.Static),
                ShortName = string.Format("{0}.{1}", jobType.Name, methodName)
            };
            FunctionDefinition definition = new FunctionDefinition(descriptor, mockInstanceFactory.Object, mockListenerFactory.Object);
            functions.Add(definition);

            // Create the composite listener - this will fail if any of the
            // function definitions indicate that they are not disabled
            HostListenerFactory factory = new HostListenerFactory(functions, singletonManager, DefaultJobActivator.Instance, null, traceWriter);
            IListener listener = await factory.CreateAsync(CancellationToken.None);

            Assert.Equal(1, traceWriter.Traces.Count);
            Assert.Equal(TraceLevel.Info, traceWriter.Traces[0].Level);
            Assert.Equal(TraceSource.Host, traceWriter.Traces[0].Source);
            Assert.Equal(string.Format("Function '{0}' is disabled", descriptor.ShortName), traceWriter.Traces[0].Message);

            Environment.SetEnvironmentVariable("EnvironmentSettingTrue", null);
        }
        public static async Task<JobHostContext> CreateAndLogHostStartedAsync(
            JobHost host,
            IStorageAccountProvider storageAccountProvider,
            IQueueConfiguration queueConfiguration,
            ITypeLocator typeLocator,
            IJobActivator activator,
            INameResolver nameResolver,
            IConsoleProvider consoleProvider,
            JobHostConfiguration config,
            CancellationToken shutdownToken,
            CancellationToken cancellationToken,
            IHostIdProvider hostIdProvider = null,
            FunctionExecutor functionExecutor = null,
            IFunctionIndexProvider functionIndexProvider = null,
            IBindingProvider bindingProvider = null,
            IHostInstanceLoggerProvider hostInstanceLogerProvider = null,
            IFunctionInstanceLoggerProvider functionInstanceLoggerProvider = null,
            IFunctionOutputLoggerProvider functionOutputLoggerProvider = null,
            IBackgroundExceptionDispatcher backgroundExceptionDispatcher = null,
            SingletonManager singletonManager = null)
        {
            if (hostIdProvider == null)
            {
                hostIdProvider = new DynamicHostIdProvider(storageAccountProvider, () => functionIndexProvider);
            }

            IExtensionTypeLocator extensionTypeLocator = new ExtensionTypeLocator(typeLocator);
            if (backgroundExceptionDispatcher == null)
            {
                backgroundExceptionDispatcher = BackgroundExceptionDispatcher.Instance;
            }
            ContextAccessor<IMessageEnqueuedWatcher> messageEnqueuedWatcherAccessor = new ContextAccessor<IMessageEnqueuedWatcher>();
            ContextAccessor<IBlobWrittenWatcher> blobWrittenWatcherAccessor = new ContextAccessor<IBlobWrittenWatcher>();
            ISharedContextProvider sharedContextProvider = new SharedContextProvider();

            // Create a wrapper TraceWriter that delegates to both the user 
            // TraceWriter specified on Config (if present), as well as to Console
            TraceWriter trace = new ConsoleTraceWriter(config.Tracing, consoleProvider.Out);

            // Register system services with the service container
            config.AddService<INameResolver>(nameResolver);

            ExtensionConfigContext context = new ExtensionConfigContext
            {
                Config = config,
                Trace = trace,
                Host = host
            };
            InvokeExtensionConfigProviders(context);

            IExtensionRegistry extensions = config.GetExtensions();
            ITriggerBindingProvider triggerBindingProvider = DefaultTriggerBindingProvider.Create(nameResolver,
                storageAccountProvider, extensionTypeLocator, hostIdProvider, queueConfiguration, backgroundExceptionDispatcher,
                messageEnqueuedWatcherAccessor, blobWrittenWatcherAccessor, sharedContextProvider, extensions, trace);

            if (bindingProvider == null)
            {
                bindingProvider = DefaultBindingProvider.Create(nameResolver, storageAccountProvider, extensionTypeLocator, messageEnqueuedWatcherAccessor, blobWrittenWatcherAccessor, extensions);
            }

            DefaultLoggerProvider loggerProvider = new DefaultLoggerProvider(storageAccountProvider, trace);

            if (singletonManager == null)
            {
                singletonManager = new SingletonManager(storageAccountProvider, backgroundExceptionDispatcher, config.Singleton, trace, config.NameResolver);
            }
            
            using (CancellationTokenSource combinedCancellationSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, shutdownToken))
            {
                CancellationToken combinedCancellationToken = combinedCancellationSource.Token;

                await WriteSiteExtensionManifestAsync(combinedCancellationToken);

                IStorageAccount dashboardAccount = await storageAccountProvider.GetDashboardAccountAsync(combinedCancellationToken);

                IHostInstanceLogger hostInstanceLogger = null;
                if (hostInstanceLogerProvider != null)
                {
                    hostInstanceLogger = await hostInstanceLogerProvider.GetAsync(combinedCancellationToken);
                }
                else
                {
                    hostInstanceLogger = await((IHostInstanceLoggerProvider)loggerProvider).GetAsync(combinedCancellationToken);
                }

                IFunctionInstanceLogger functionInstanceLogger = null;
                if (functionInstanceLoggerProvider != null)
                {
                    functionInstanceLogger = await functionInstanceLoggerProvider.GetAsync(combinedCancellationToken);
                }
                else
                {
                    functionInstanceLogger = (IFunctionInstanceLogger)(await((IFunctionInstanceLoggerProvider)loggerProvider).GetAsync(combinedCancellationToken));
                }

                IFunctionOutputLogger functionOutputLogger = null;
                if (functionOutputLoggerProvider != null)
                {
                    functionOutputLogger = await functionOutputLoggerProvider.GetAsync(combinedCancellationToken);
                }
                else
                {
                    functionOutputLogger = (IFunctionOutputLogger)(await((IFunctionOutputLoggerProvider)loggerProvider).GetAsync(combinedCancellationToken));
                }

                if (functionExecutor == null)
                {
                    functionExecutor = new FunctionExecutor(functionInstanceLogger, functionOutputLogger, backgroundExceptionDispatcher, trace);
                }

                if (functionIndexProvider == null)
                {
                    functionIndexProvider = new FunctionIndexProvider(typeLocator, triggerBindingProvider, bindingProvider, activator, functionExecutor, extensions, singletonManager);
                }

                IFunctionIndex functions = await functionIndexProvider.GetAsync(combinedCancellationToken);
                IListenerFactory functionsListenerFactory = new HostListenerFactory(functions.ReadAll(), singletonManager, activator, nameResolver, trace);

                IFunctionExecutor hostCallExecutor;
                IListener listener;
                HostOutputMessage hostOutputMessage;

                if (dashboardAccount != null)
                {
                    string hostId = await hostIdProvider.GetHostIdAsync(cancellationToken);

                    string sharedQueueName = HostQueueNames.GetHostQueueName(hostId);
                    IStorageQueueClient dashboardQueueClient = dashboardAccount.CreateQueueClient();
                    IStorageQueue sharedQueue = dashboardQueueClient.GetQueueReference(sharedQueueName);
                    IListenerFactory sharedQueueListenerFactory = new HostMessageListenerFactory(sharedQueue,
                        queueConfiguration, backgroundExceptionDispatcher, trace, functions,
                        functionInstanceLogger, functionExecutor);

                    Guid hostInstanceId = Guid.NewGuid();
                    string instanceQueueName = HostQueueNames.GetHostQueueName(hostInstanceId.ToString("N"));
                    IStorageQueue instanceQueue = dashboardQueueClient.GetQueueReference(instanceQueueName);
                    IListenerFactory instanceQueueListenerFactory = new HostMessageListenerFactory(instanceQueue,
                        queueConfiguration, backgroundExceptionDispatcher, trace, functions,
                        functionInstanceLogger, functionExecutor);

                    HeartbeatDescriptor heartbeatDescriptor = new HeartbeatDescriptor
                    {
                        SharedContainerName = HostContainerNames.Hosts,
                        SharedDirectoryName = HostDirectoryNames.Heartbeats + "/" + hostId,
                        InstanceBlobName = hostInstanceId.ToString("N"),
                        ExpirationInSeconds = (int)HeartbeatIntervals.ExpirationInterval.TotalSeconds
                    };

                    IStorageBlockBlob blob = dashboardAccount.CreateBlobClient()
                        .GetContainerReference(heartbeatDescriptor.SharedContainerName)
                        .GetBlockBlobReference(heartbeatDescriptor.SharedDirectoryName + "/" + heartbeatDescriptor.InstanceBlobName);
                    IRecurrentCommand heartbeatCommand = new UpdateHostHeartbeatCommand(new HeartbeatCommand(blob));

                    IEnumerable<MethodInfo> indexedMethods = functions.ReadAllMethods();
                    Assembly hostAssembly = GetHostAssembly(indexedMethods);
                    string displayName = hostAssembly != null ? hostAssembly.GetName().Name : "Unknown";

                    hostOutputMessage = new DataOnlyHostOutputMessage
                    {
                        HostInstanceId = hostInstanceId,
                        HostDisplayName = displayName,
                        SharedQueueName = sharedQueueName,
                        InstanceQueueName = instanceQueueName,
                        Heartbeat = heartbeatDescriptor,
                        WebJobRunIdentifier = WebJobRunIdentifier.Current
                    };

                    hostCallExecutor = CreateHostCallExecutor(instanceQueueListenerFactory, heartbeatCommand,
                        backgroundExceptionDispatcher, shutdownToken, functionExecutor);
                    IListenerFactory hostListenerFactory = new CompositeListenerFactory(functionsListenerFactory,
                        sharedQueueListenerFactory, instanceQueueListenerFactory);
                    listener = CreateHostListener(hostListenerFactory, heartbeatCommand, backgroundExceptionDispatcher, shutdownToken);

                    // Publish this to Azure logging account so that a web dashboard can see it. 
                    await LogHostStartedAsync(functions, hostOutputMessage, hostInstanceLogger, combinedCancellationToken);
                }
                else
                {
                    hostCallExecutor = new ShutdownFunctionExecutor(shutdownToken, functionExecutor);

                    IListener factoryListener = new ListenerFactoryListener(functionsListenerFactory);
                    IListener shutdownListener = new ShutdownListener(shutdownToken, factoryListener);
                    listener = shutdownListener;

                    hostOutputMessage = new DataOnlyHostOutputMessage();
                }

                functionExecutor.HostOutputMessage = hostOutputMessage;

                IEnumerable<FunctionDescriptor> descriptors = functions.ReadAllDescriptors();
                int descriptorsCount = descriptors.Count();

                if (descriptorsCount == 0)
                {
                    trace.Warning("No functions found. Try making job classes and methods public.", TraceSource.Indexing);
                }
                else
                {
                    StringBuilder functionsTrace = new StringBuilder();
                    functionsTrace.AppendLine("Found the following functions:");
                    
                    foreach (FunctionDescriptor descriptor in descriptors)
                    {
                        functionsTrace.AppendLine(descriptor.FullName);
                    }

                    trace.Info(functionsTrace.ToString(), TraceSource.Indexing);
                }

                return new JobHostContext(functions, hostCallExecutor, listener, trace);
            }
        }