[Bug fix] Make sure running language worker processes tracked (#3938)

* Work to publish worker ready event => worker process tracked => later able to be disposed

* add a test to make sure # running node processes does not change on file change

* Fix ShutdownChannels

Author: mhoeger

src/WebJobs.Script/Rpc/LanguageWorkerChannel.cs

@@ -278,13 +278,14 @@ internal void PublishRpcChannelReadyEvent(RpcEvent initEvent)
                 HandleWorkerError(exc);
                 return;
             }
-            if (_functionRegistrations == null)
+
+            RpcChannelReadyEvent readyEvent = new RpcChannelReadyEvent(_workerId, _workerConfig.Language, this, _initMessage.WorkerVersion, _initMessage.Capabilities);
+            _eventManager.Publish(readyEvent);
+
+            if (_functionRegistrations != null)
             {
-                RpcChannelReadyEvent readyEvent = new RpcChannelReadyEvent(_workerId, _workerConfig.Language, this, _initMessage.WorkerVersion, _initMessage.Capabilities);
-                _eventManager.Publish(readyEvent);
-                return;
+                RegisterFunctions(_functionRegistrations);
             }
-            RegisterFunctions(_functionRegistrations);
         }
 
         public void RegisterFunctions(IObservable<FunctionRegistrationContext> functionRegistrations)

src/WebJobs.Script/Rpc/LanguageWorkerChannelManager.cs

@@ -186,7 +186,7 @@ public void ShutdownStandbyChannels(IEnumerable<FunctionMetadata> functions)
 
         public void ShutdownChannels()
         {
-            foreach (string runtime in _workerChannels.Keys)
+            foreach (string runtime in _workerChannels.Keys.ToList())
             {
                 _logger.LogInformation("Shutting down language worker channel for runtime:{runtime}", runtime);
                 _workerChannels[runtime]?.Dispose();

test/WebJobs.Script.Tests.Integration/WebHostEndToEnd/SamplesEndToEndTests_Node.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -426,6 +427,21 @@ await TestHelpers.Await(async () =>
             Assert.Equal(initialTimestamp, timestamp);
         }
 
+        [Fact]
+        public async Task NodeProcessCount_SameAfterFileChange()
+        {
+            // Count number of node processes before restart
+            int initialProcessCount = GetProcessCountByName("node");
+            await SharedDirectory_ReloadsOnFileChange();
+            // Count number of node processes after restart
+            int proccessCountAfterReload = GetProcessCountByName("node");
+            Assert.Equal(proccessCountAfterReload, initialProcessCount);
+        }
+        private static int GetProcessCountByName(string processName)
+        {
+            return Process.GetProcessesByName(processName).Length;
+        }
+
         [Fact]
         public async Task HttpTrigger_Disabled_SucceedsWithAdminKey()
         {