Adding optional parameter support

release_notes.md

@@ -10,8 +10,8 @@
 
 ### Microsoft.Azure.Functions.Worker.Core <version>
 
-- <entry>
+- Adding optional parameter support (#1868)
 
 ### Microsoft.Azure.Functions.Worker.Grpc <version>
 
-- <entry>
+- Adding optional parameter support (#1868)

src/DotNetWorker.Core/Context/Features/DefaultFunctionInputBindingFeature.cs

@@ -5,6 +5,9 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.Serialization;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Azure.Functions.Worker.Converters;
@@ -97,6 +100,21 @@ public async ValueTask<FunctionInputBindingResult> BindFunctionInputAsync(Functi
                         errors.Add(
                             $"Cannot convert input parameter '{param.Name}' to type '{param.Type.FullName}' from type '{source.GetType().FullName}'. Error:{bindingResult.Error}");
                     }
+                    else if (bindingResult.Status == ConversionStatus.Unhandled)
+                    {
+                        // If still unhandled after going through all converters,check an explicit default value was provided for the parameter.
+                        if (param.DefaultValue is not null)
+                        {
+                            parameterValues[i] = param.DefaultValue;
+                        }
+                        else
+                        {
+                            // We could not find a value for this param. should throw.
+                            errors ??= new List<string>();
+                            errors.Add(
+                                $"Could not populate the value for '{param.Name}' parameter. Consider updating the parameter with a default value.");
+                        }
+                    }
                 }
 
                 // found errors

src/DotNetWorker.Core/Definition/FunctionParameter.cs

@@ -22,6 +22,17 @@ public FunctionParameter(string name, Type type)
         {
         }
 
+        /// <summary>
+        /// Creates an instance of the <see cref="FunctionParameter"/> class.
+        /// </summary>
+        /// <param name="name">The parameter name.</param>
+        /// <param name="type">The <see cref="System.Type"/> of the parameter.</param>
+        /// <param name="defaultValue">Default value of the parameter.</param>
+        public FunctionParameter(string name, Type type, object? defaultValue)
+            : this(name, type, defaultValue, ImmutableDictionary<string, object>.Empty)
+        {
+        }
+
         /// <summary>
         /// Creates an instance of the <see cref="FunctionParameter"/> class.
         /// </summary>
@@ -35,6 +46,21 @@ public FunctionParameter(string name, Type type, IReadOnlyDictionary<string, obj
             Properties = properties ?? throw new ArgumentNullException(nameof(properties));
         }
 
+        /// <summary>
+        /// Creates an instance of the <see cref="FunctionParameter"/> class.
+        /// </summary>
+        /// <param name="name">The parameter name.</param>
+        /// <param name="type">The <see cref="System.Type"/> of the parameter.</param>
+        /// <param name="defaultValue">Default value of the parameter.</param>
+        /// <param name="properties">The properties of the parameter.</param>
+        public FunctionParameter(string name, Type type, object? defaultValue, IReadOnlyDictionary<string, object> properties)
+        {
+            Name = name ?? throw new ArgumentNullException(nameof(name));
+            Type = type ?? throw new ArgumentNullException(nameof(type));
+            DefaultValue = defaultValue ?? default;
+            Properties = properties ?? throw new ArgumentNullException(nameof(properties));
+        }
+
         /// <summary>
         /// Gets the parameter name.
         /// </summary>
@@ -45,6 +71,11 @@ public FunctionParameter(string name, Type type, IReadOnlyDictionary<string, obj
         /// </summary>
         public Type Type { get; }
 
+        /// <summary>
+        /// Gets the default value of the parameter if exists, else null.
+        /// </summary>
+        public object? DefaultValue { get; }
+
         /// <summary>
         /// A dictionary holding properties of this parameter.
         /// </summary>

src/DotNetWorker.Grpc/Definition/GrpcFunctionDefinition.cs

@@ -56,7 +56,7 @@ public GrpcFunctionDefinition(FunctionLoadRequest loadRequest, IMethodInfoLocato
             Parameters = methodInfoLocator.GetMethod(PathToAssembly, EntryPoint)
                 .GetParameters()
                 .Where(p => p.Name != null)
-                .Select(p => new FunctionParameter(p.Name!, p.ParameterType, GetAdditionalPropertiesDictionary(p)))
+                .Select(p => new FunctionParameter(p.Name!, p.ParameterType, p.HasDefaultValue ? p.DefaultValue! : null, GetAdditionalPropertiesDictionary(p)))
                 .ToImmutableArray();
         }
 

test/DotNetWorkerTests/DefaultModelBindingFeatureTests.cs

@@ -1,10 +1,12 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Text.Json;
 using System.Threading;
 using Azure.Core.Serialization;
 using Microsoft.Azure.Functions.Worker.Context.Features;
+using Microsoft.Azure.Functions.Worker.Http;
 using Microsoft.Azure.Functions.Worker.Tests.Features;
 using Microsoft.Extensions.DependencyInjection;
 using Xunit;
@@ -59,6 +61,73 @@ public async void BindFunctionInputAsync_Populates_ParametersUsingConverters()
             Assert.Equal("0ab4800e-1308-4e9f-be5f-4372717e68eb", guid.ToString());
         }
 
+        [Fact]
+        public async void BindFunctionInputAsync_Populates_Parameter_Using_DefaultValue_When_CouldNot_Populate_From_InputData()
+        {
+            var features = new InvocationFeatures(Enumerable.Empty<IInvocationFeatureProvider>());
+            var httpFunctionDefinition = new TestFunctionDefinition(parameters: new FunctionParameter[]
+            {
+                 new("req", typeof(HttpRequestData)),
+                 new("fooId", typeof(int), defaultValue: 100)
+            },
+            inputBindings: new Dictionary<string, BindingMetadata>
+            {
+                 { "req", new TestBindingMetadata("req","httpTrigger",BindingDirection.In) }
+            });  ;
+            features.Set<FunctionDefinition>(httpFunctionDefinition);
+
+            var functionContext = new TestFunctionContext(httpFunctionDefinition, invocation: null, CancellationToken.None, serviceProvider: _serviceProvider, features: features);
+            var grpcHttpReq = new GrpcHttpRequestData(TestUtility.CreateRpcHttp(), functionContext);
+            var functionBindings = new TestFunctionBindingsFeature
+            {
+                InputData = new ReadOnlyDictionary<string, object>(new Dictionary<string, object> { { "req", grpcHttpReq } })
+            };
+            features.Set<IFunctionBindingsFeature>(functionBindings);
+            features.Set(_serviceProvider.GetService<IInputConversionFeature>());
+
+            // Act
+            var bindingResult = await _functionInputBindingFeature.BindFunctionInputAsync(functionContext);
+            var parameterValuesArray = bindingResult.Values;
+
+            // Assert
+            var httpReqData = TestUtility.AssertIsTypeAndConvert<HttpRequestData>(parameterValuesArray[0]);
+            Assert.NotNull(httpReqData);
+            var fooId = TestUtility.AssertIsTypeAndConvert<int>(parameterValuesArray[1]);
+            Assert.Equal(100, fooId);
+        }
+
+        [Fact]
+        public async void BindFunctionInputAsync_Throws_When_Explicit_OptionalParametersValueNotPresent()
+        {
+            // 'fooId' is a parameter defined for the function without a default value
+            // and 'InputData' does not have a corresponding entry for that we could use to populate that parameter.
+
+            IInvocationFeatures features = new InvocationFeatures(Enumerable.Empty<IInvocationFeatureProvider>());
+            var httpFunctionDefinition = new TestFunctionDefinition(parameters: new FunctionParameter[]
+            {
+                 new("req", typeof(HttpRequestData)),
+                 new("fooId", typeof(int))
+            },
+            inputBindings: new Dictionary<string, BindingMetadata>
+            {
+                 { "req", new TestBindingMetadata("req","httpTrigger",BindingDirection.In) }
+            }); ;
+            features.Set<FunctionDefinition>(httpFunctionDefinition);
+
+            var functionContext = new TestFunctionContext(httpFunctionDefinition, invocation: null, CancellationToken.None, serviceProvider: _serviceProvider, features: features);
+            var grpcHttpReq = new GrpcHttpRequestData(TestUtility.CreateRpcHttp(), functionContext);
+            var functionBindings = new TestFunctionBindingsFeature
+            {
+                InputData = new ReadOnlyDictionary<string, object>(new Dictionary<string, object> { { "req", grpcHttpReq } })
+            };
+            features.Set<IFunctionBindingsFeature>(functionBindings);
+            features.Set(_serviceProvider.GetService<IInputConversionFeature>());
+
+            // Assert
+            var exception = await Assert.ThrowsAsync<FunctionInputConverterException>(async () => await _functionInputBindingFeature.BindFunctionInputAsync(functionContext));
+            Assert.Equal("Error converting 1 input parameters for Function 'TestName': Could not populate the value for 'fooId' parameter. Consider updating the parameter with a default value.", exception.Message);
+        }
+
         [Fact]
         public async void BindFunctionInputAsync_Returns_Cached_Value_When_Called_SecondTime()
         {

test/DotNetWorkerTests/FunctionContextHttpExtensionTests.cs

@@ -85,7 +85,7 @@ public async Task GetHttpRequestDataAsync_Works_For_Http_Invocation()
             _features.Set<FunctionDefinition>(httpFunctionDefinition);
 
             _defaultFunctionContext = new DefaultFunctionContext(_serviceScopeFactory, _features, CancellationToken.None);
-            var grpcHttpReq = new GrpcHttpRequestData(CreateRpcHttp(), _defaultFunctionContext);
+            var grpcHttpReq = new GrpcHttpRequestData(TestUtility.CreateRpcHttp(), _defaultFunctionContext);
             var functionBindings = new TestFunctionBindingsFeature
             {
                 InputData = new ReadOnlyDictionary<string, object>(new Dictionary<string, object> { { "req", grpcHttpReq } })
@@ -118,7 +118,7 @@ public void GetHttpResponseData_Works_For_Http_Invocation()
             _features.Set<FunctionDefinition>(new TestFunctionDefinition());
 
             _defaultFunctionContext = new DefaultFunctionContext(_serviceScopeFactory, _features, CancellationToken.None);
-            var grpcHttpReq = new GrpcHttpRequestData(CreateRpcHttp(), _defaultFunctionContext);
+            var grpcHttpReq = new GrpcHttpRequestData(TestUtility.CreateRpcHttp(), _defaultFunctionContext);
             var functionBindings = new TestFunctionBindingsFeature
             {
                 InputData = new ReadOnlyDictionary<string, object>(new Dictionary<string, object> { { "req", grpcHttpReq } }),
@@ -153,7 +153,7 @@ public void GetHttpResponseData_Works_For_Http_Invocation_POCO_OutputBinding_Pro
             }));
 
             _defaultFunctionContext = new DefaultFunctionContext(_serviceScopeFactory, _features, CancellationToken.None);
-            var grpcHttpReq = new GrpcHttpRequestData(CreateRpcHttp(), _defaultFunctionContext);
+            var grpcHttpReq = new GrpcHttpRequestData(TestUtility.CreateRpcHttp(), _defaultFunctionContext);
             var functionBindings = new TestFunctionBindingsFeature
             {
                 InputData = new ReadOnlyDictionary<string, object>(new Dictionary<string, object> { { "req", grpcHttpReq } })
@@ -179,17 +179,5 @@ public void GetHttpResponseData_Works_For_Http_Invocation_POCO_OutputBinding_Pro
             HttpResponseData actual2 = _defaultFunctionContext.GetHttpResponseData();
             Assert.True(actual2.Headers.First(a => a.Key == "X-Foo-Id").Value.Any());
         }
-
-        private RpcHttp CreateRpcHttp()
-        {
-            var rpcHttp = new RpcHttp
-            {
-                Url = "https://m.sn"
-            };
-            rpcHttp.NullableHeaders["Accept-Encoding"] = new NullableString() { Value = "gzip, deflate" };
-            rpcHttp.NullableHeaders["Cookie"] = new NullableString() { Value = "theme=light; x-token=foo" };
-
-            return rpcHttp;
-        }
     }
 }

test/DotNetWorkerTests/TestUtility.cs

@@ -87,5 +87,17 @@ public static InvocationRequest CreateInvocationRequestWithNullRetryContext(stri
                 RetryContext = null
             };
         }
+
+        internal static RpcHttp CreateRpcHttp()
+        {
+            var rpcHttp = new RpcHttp
+            {
+                Url = "https://m.sn"
+            };
+            rpcHttp.NullableHeaders["Accept-Encoding"] = new NullableString() { Value = "gzip, deflate" };
+            rpcHttp.NullableHeaders["Cookie"] = new NullableString() { Value = "theme=light; x-token=foo" };
+
+            return rpcHttp;
+        }
     }
 }