Added telemetry to indicate when ParameterBindingData is being used (#9028)

* Telemetry for parameter binding data

Author: surgupta-msft

src/WebJobs.Script.Grpc/Channel/GrpcWorkerChannel.cs

@@ -21,6 +21,7 @@
 using Microsoft.Azure.WebJobs.Script.Description;
 using Microsoft.Azure.WebJobs.Script.Diagnostics;
 using Microsoft.Azure.WebJobs.Script.Eventing;
+using Microsoft.Azure.WebJobs.Script.Extensions;
 using Microsoft.Azure.WebJobs.Script.Grpc.Eventing;
 using Microsoft.Azure.WebJobs.Script.Grpc.Extensions;
 using Microsoft.Azure.WebJobs.Script.Grpc.Messages;
@@ -590,6 +591,11 @@ internal FunctionLoadRequest GetFunctionLoadRequest(FunctionMetadata metadata, M
                 BindingInfo bindingInfo = binding.ToBindingInfo();
 
                 request.Metadata.Bindings.Add(binding.Name, bindingInfo);
+
+                if (binding.SupportsDeferredBinding() && !binding.SkipDeferredBinding())
+                {
+                    _metricsLogger.LogEvent(MetricEventNames.FunctionBindingDeferred, functionName: metadata.Name);
+                }
             }
 
             foreach (var property in metadata.Properties)

src/WebJobs.Script/Diagnostics/MetricEventNames.cs

@@ -52,6 +52,7 @@ public static class MetricEventNames
         // function level events
         public const string FunctionInvokeLatency = "function.invoke.latency";
         public const string FunctionBindingTypeFormat = "function.binding.{0}";
+        public const string FunctionBindingDeferred = "function.binding.deferred";
         public const string FunctionCompileLatencyByLanguageFormat = "function.compile.{0}.latency";
         public const string FunctionInvokeThrottled = "function.invoke.throttled";
         public const string FunctionUserLog = "function.userlog";

test/WebJobs.Script.Tests/Workers/Rpc/GrpcWorkerChannelTests.cs

@@ -555,6 +555,63 @@ public async Task SendLoadRequests_PublishesOutboundEvents()
             Assert.Equal(3, functionLoadLogs.Count()); // one WorkInitRequest, two FunctionLoadRequest
         }
 
+        [Fact]
+        public async Task SendLoadRequests_SkipParameterBindingData()
+        {
+            await CreateDefaultWorkerChannel();
+            _metricsLogger.ClearCollections();
+
+            var binding = new BindingMetadata()
+            {
+                Name = "abc",
+                Type = "BlobTrigger"
+            };
+
+            binding.Properties.Add(ScriptConstants.SkipDeferredBindingKey, true);
+            binding.Properties.Add(ScriptConstants.SupportsDeferredBindingKey, true);
+
+            IEnumerable<FunctionMetadata> functionMetadata = GetTestFunctionsList("node");
+            foreach (var function in functionMetadata)
+            {
+                function.Bindings.Add(binding);
+            }
+
+            _workerChannel.SetupFunctionInvocationBuffers(functionMetadata);
+            _workerChannel.SendFunctionLoadRequests(null, TimeSpan.FromMinutes(5));
+            await Task.Delay(500);
+            AreExpectedMetricsGenerated();
+            Assert.Equal(0, _metricsLogger.LoggedEvents.Count(e => e.Contains(MetricEventNames.FunctionBindingDeferred)));
+        }
+
+        [Fact]
+        public async Task SendLoadRequests_SupportParameterBindingData()
+        {
+            await CreateDefaultWorkerChannel();
+            _metricsLogger.ClearCollections();
+
+            var binding = new BindingMetadata()
+            {
+                Name = "abc",
+                Type = "BlobTrigger"
+            };
+
+            binding.Properties.Add(ScriptConstants.SupportsDeferredBindingKey, true);
+
+            IEnumerable<FunctionMetadata> functionMetadata = GetTestFunctionsList("node");
+            foreach (var function in functionMetadata)
+            {
+                function.Bindings.Add(binding);
+            }
+
+            _workerChannel.SetupFunctionInvocationBuffers(functionMetadata);
+            _workerChannel.SendFunctionLoadRequests(null, TimeSpan.FromMinutes(5));
+            await Task.Delay(500);
+            AreExpectedMetricsGenerated();
+            Assert.Equal(2, _metricsLogger.LoggedEvents.Count(e => e.Contains(MetricEventNames.FunctionBindingDeferred)));
+            Assert.Equal(1, _metricsLogger.LoggedEvents.Count(e => e.Contains($"{MetricEventNames.FunctionBindingDeferred}_js1")));
+            Assert.Equal(1, _metricsLogger.LoggedEvents.Count(e => e.Contains($"{MetricEventNames.FunctionBindingDeferred}_js2")));
+        }
+
         [Fact]
         public async Task SendLoadRequestCollection_PublishesOutboundEvents()
         {