WatchDirectories fix for Node.js (#954)

Author: mathewc

WebJobs.Script.sln

@@ -353,6 +353,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Shared", "Shared", "{C9FCBC
 	ProjectSection(SolutionItems) = preProject
 		sample\Shared\Message.csx = sample\Shared\Message.csx
 		sample\Shared\Order.csx = sample\Shared\Order.csx
+		sample\Shared\test.js = sample\Shared\test.js
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "ManualTrigger-CSharp", "ManualTrigger-CSharp", "{EB3A602B-4B32-4742-B4A2-39445BD2FBE3}"

sample/HttpTrigger/index.js

@@ -1,4 +1,6 @@
-module.exports = function (context, req) {
+var test = require('../Shared/test');
+
+module.exports = function (context, req) {
     context.log('Node.js HTTP trigger function processed a request. Name=%s', req.query.name);
 
     var headerValue = req.headers['test-header'];
@@ -19,9 +21,10 @@
     else {
         res = {
             status: 200,
-            body: "Hello " + req.query.name,
+            body: test.greeting(req.query.name),
             headers: {
-                'Content-Type': 'text/plain'
+                'Content-Type': 'text/plain',
+                'Shared-Module': test.timestamp
             }
         };
     }

sample/Shared/test.js

@@ -0,0 +1,8 @@
+var timestamp = new Date().getTime();
+
+module.exports = {
+    timestamp: timestamp,
+    greeting: function (name) {
+        return 'Hello ' + name;
+    }
+};

src/WebJobs.Script/Description/Node/NodeFunctionInvoker.cs

@@ -257,6 +257,11 @@ internal static object ConvertBindingValue(object value)
             return value;
         }
 
+        internal static void OnHostRestart()
+        {
+            ClearRequireCacheFunc(null).GetAwaiter().GetResult();
+        }
+
         protected override void OnScriptFileChanged(object sender, FileSystemEventArgs e)
         {
             if (_scriptFunc == null)

src/WebJobs.Script/Host/ScriptHost.cs

@@ -310,9 +310,7 @@ protected virtual void Initialize()
                 {
                     TraceWriter.Info(string.Format(CultureInfo.InvariantCulture, "File change of type '{0}' detected for '{1}'", e.ChangeType, e.FullPath));
                     TraceWriter.Info("Host configuration has changed. Signaling restart.");
-
-                    // signal host restart
-                    _restartEvent.Set();
+                    RestartHost();
                 };
                 _restart = _restart.Debounce(500);
 
@@ -407,6 +405,16 @@ internal static Collection<CustomAttributeBuilder> CreateTypeAttributes(ScriptHo
             return customAttributes;
         }
 
+        private void RestartHost()
+        {
+            // signal host restart
+            _restartEvent.Set();
+
+            // whenever we're restarting the host, we want to let the Node
+            // invoker know so it can clear the require cache, etc.
+            NodeFunctionInvoker.OnHostRestart();
+        }
+
         /// <summary>
         /// Whenever the debug marker file changes we update our debug timeout
         /// </summary>

test/WebJobs.Script.Tests/SamplesEndToEndTests.cs

@@ -359,6 +359,41 @@ public async Task HttpTrigger_CustomRoute_Post_ReturnsExpectedResponse()
             Assert.Equal((string)product["name"], (string)resultProduct["name"]);
         }
 
+        [Fact]
+        public async Task SharedDirectory_Node_ReloadsOnFileChange()
+        {
+            string uri = "api/httptrigger?code=hyexydhln844f2mb7hgsup2yf8dowlb0885mbiq1&name=Mathew";
+            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, uri);
+            HttpResponseMessage response = await _fixture.HttpClient.SendAsync(request);
+            string initialTimestamp = response.Headers.GetValues("Shared-Module").First();
+
+            // make the request again and verify the timestamp is the same
+            request = new HttpRequestMessage(HttpMethod.Get, uri);
+            response = await _fixture.HttpClient.SendAsync(request);
+            string timestamp = response.Headers.GetValues("Shared-Module").First();
+            Assert.Equal(initialTimestamp, timestamp);
+
+            // now "touch" a file in the shared directory to trigger a restart
+            string sharedModulePath = Path.Combine(_fixture.HostSettings.ScriptPath, "Shared\\test.js");
+            File.SetLastWriteTimeUtc(sharedModulePath, DateTime.UtcNow);
+
+            // wait for the module to be reloaded
+            await TestHelpers.Await(() =>
+            {
+                request = new HttpRequestMessage(HttpMethod.Get, uri);
+                response = _fixture.HttpClient.SendAsync(request).GetAwaiter().GetResult();
+                timestamp = response.Headers.GetValues("Shared-Module").First();
+                return initialTimestamp != timestamp;
+            }, timeout: 5000, pollingInterval: 1000);
+            Assert.NotEqual(initialTimestamp, timestamp);
+
+            initialTimestamp = timestamp;
+            request = new HttpRequestMessage(HttpMethod.Get, uri);
+            response = await _fixture.HttpClient.SendAsync(request);
+            timestamp = response.Headers.GetValues("Shared-Module").First();
+            Assert.Equal(initialTimestamp, timestamp);
+        }
+
         [Fact]
         public async Task HttpTrigger_CSharp_CustomRoute_ReturnsExpectedResponse()
         {