[Issue #179]: Adds System.Threading.Timer for aggregate change delay.

ReadMe.md

@@ -1471,6 +1471,12 @@ Also, invocations complete using the outdated version of your script. Weigh thes
 This value does nothing if `OutOfProcessNodeJSServiceOptions.EnableFileWatching` is `false` and `OutOfProcessNodeJSServiceOptions.NumProcessRetries` is 0.  
 
 Defaults to `true`.  
+##### OutOfProcessNodeJSServiceOptions.AggregateTimeout
+
+Add a delay before restarting the NodeJS service once the first file changed. This allows OutOfProcessNodeJSService to aggregate any other changes made during this time period into one rebuild.  
+```csharp
+public int AggregateTimeout { get; set; }
+```
 <!-- OutOfProcessNodeJSServiceOptions generated docs -->
 <!-- HttpNodeJSServiceOptions generated docs -->
 

src/NodeJS/NodeJSServiceImplementations/OutOfProcess/OutOfProcessNodeJSService.cs

@@ -45,9 +45,12 @@ public abstract class OutOfProcessNodeJSService : INodeJSService
         private readonly int _invocationTimeoutMS;
         private readonly ConcurrentDictionary<Task, object?> _trackedInvokeTasks; // TODO use ConcurrentSet when it's available - https://github.com/dotnet/runtime/issues/16443
         private readonly bool _trackInvokeTasks;
+        private readonly object _fileChangeAggregateLock = new();
+        private readonly int _fileChangeAggregateDelayInMilliseconds;
 
         private bool _disposed;
         private volatile INodeJSProcess? _nodeJSProcess; // Volatile since it's used in a double checked lock
+        private Timer? _fileChangeAggregateTimer;
 
         /// <summary>
         /// <para>This regex is used to determine successful initialization of the process.</para>
@@ -88,6 +91,8 @@ protected OutOfProcessNodeJSService(INodeJSProcessFactory nodeProcessFactory,
             _serverScriptAssembly = serverScriptAssembly;
             Logger = logger;
 
+            _fileChangeAggregateDelayInMilliseconds = _options.AggregateTimeout;
+
             _debugLoggingEnabled = Logger.IsEnabled(LogLevel.Debug);
             _warningLoggingEnabled = Logger.IsEnabled(LogLevel.Warning);
             _infoLoggingEnabled = Logger.IsEnabled(LogLevel.Information);
@@ -576,12 +581,38 @@ internal virtual void FileChangedHandler()
                 Logger.LogDebug(string.Format(Strings.LogDebug_FileChangedHandlerInvokedForProcess, _nodeJSProcess?.SafeID));
             }
 
+            lock (_fileChangeAggregateLock)
+            {
+                // If the timer is already running, disable it.
+                _fileChangeAggregateTimer?.Change(Timeout.Infinite, Timeout.Infinite);
+
+                // Start or restart the timer.
+                if (_fileChangeAggregateTimer == null)
+                {
+                    _fileChangeAggregateTimer = new Timer(ExecuteFileChangeAggregate, null, _fileChangeAggregateDelayInMilliseconds, Timeout.Infinite);
+                }
+                else
+                {
+                    _fileChangeAggregateTimer.Change(_fileChangeAggregateDelayInMilliseconds, Timeout.Infinite);
+                }
+            }
+        }
+
+        // Delegate for timer execution
+        private void ExecuteFileChangeAggregate(object? state)
+        {
 #pragma warning disable CS4014
             // No need to await
             //
             // Note that we need to reconnect even if we've just connected so that the changed file is loaded.
             MoveToNewProcessAsync(true);
 #pragma warning restore CS4014
+
+            lock (_fileChangeAggregateLock)
+            {
+                _fileChangeAggregateTimer?.Dispose();
+                _fileChangeAggregateTimer = null;
+            }
         }
 
         // Just connected refers to the situation where _nodeJSProcess.Connected is true but _connectingLock has not been released

src/NodeJS/NodeJSServiceImplementations/OutOfProcess/OutOfProcessNodeJSServiceOptions.cs

@@ -129,5 +129,13 @@ public class OutOfProcessNodeJSServiceOptions
         /// <para>Defaults to <c>true</c>.</para>
         /// </remarks>
         public bool GracefulProcessShutdown { get; set; } = true;
+
+        /// <summary>
+        /// Add a delay before restarting the NodeJS service once the first file changed. This allows OutOfProcessNodeJSService to aggregate any other changes made during this time period into one rebuild.
+        /// </summary>
+        /// <para>Value is set in milliseconds</para>
+        /// <para>This value does nothing if <see cref="EnableFileWatching"/> is <c>false</c></para>
+        /// <para>Defaults to <c>600</c>.</para>
+        public int AggregateTimeout { get; set; } = 600;
     }
 }

src/NodeJS/packages.lock.json

@@ -196,6 +196,15 @@
           "Microsoft.Extensions.Options": "6.0.0"
         }
       },
+      "Microsoft.NETFramework.ReferenceAssemblies": {
+        "type": "Direct",
+        "requested": "[1.0.3, )",
+        "resolved": "1.0.3",
+        "contentHash": "vUc9Npcs14QsyOD01tnv/m8sQUnGTGOw1BCmKcv77LBJY7OxhJ+zJF7UD/sCL3lYNFuqmQEVlkfS4Quif6FyYg==",
+        "dependencies": {
+          "Microsoft.NETFramework.ReferenceAssemblies.net461": "1.0.3"
+        }
+      },
       "Microsoft.SourceLink.GitHub": {
         "type": "Direct",
         "requested": "[1.1.1, )",
@@ -335,6 +344,11 @@
           "System.Runtime.CompilerServices.Unsafe": "6.0.0"
         }
       },
+      "Microsoft.NETFramework.ReferenceAssemblies.net461": {
+        "type": "Transitive",
+        "resolved": "1.0.3",
+        "contentHash": "AmOJZwCqnOCNp6PPcf9joyogScWLtwy0M1WkqfEQ0M9nYwyDD7EX9ZjscKS5iYnyvteX7kzSKFCKt9I9dXA6mA=="
+      },
       "Microsoft.SourceLink.Common": {
         "type": "Transitive",
         "resolved": "1.1.1",

test/NodeJS/packages.lock.json

@@ -1376,6 +1376,15 @@
           "Microsoft.CodeCoverage": "17.0.0"
         }
       },
+      "Microsoft.NETFramework.ReferenceAssemblies": {
+        "type": "Direct",
+        "requested": "[1.0.3, )",
+        "resolved": "1.0.3",
+        "contentHash": "vUc9Npcs14QsyOD01tnv/m8sQUnGTGOw1BCmKcv77LBJY7OxhJ+zJF7UD/sCL3lYNFuqmQEVlkfS4Quif6FyYg==",
+        "dependencies": {
+          "Microsoft.NETFramework.ReferenceAssemblies.net461": "1.0.3"
+        }
+      },
       "Moq": {
         "type": "Direct",
         "requested": "[4.16.1, )",
@@ -1527,6 +1536,11 @@
           "System.Runtime.CompilerServices.Unsafe": "6.0.0"
         }
       },
+      "Microsoft.NETFramework.ReferenceAssemblies.net461": {
+        "type": "Transitive",
+        "resolved": "1.0.3",
+        "contentHash": "AmOJZwCqnOCNp6PPcf9joyogScWLtwy0M1WkqfEQ0M9nYwyDD7EX9ZjscKS5iYnyvteX7kzSKFCKt9I9dXA6mA=="
+      },
       "System.Buffers": {
         "type": "Transitive",
         "resolved": "4.5.1",